Merge pull request #1203 from rouault/cpp_conversion

Conversion of most C files to C++

237 files changed, 2881 insertions, 2539 deletions

diff --git a/src/proj_4D_api.c b/src/4D_api.cpp
index 75a061a0..88210348 100644
--- a/src/proj_4D_api.c
+++ b/src/4D_api.cpp
@@ -53,6 +53,10 @@ PJ_COORD proj_coord (double x, double y, double z, double t) {
     return res;
 }
 
+static PJ_DIRECTION opposite_direction(PJ_DIRECTION dir) {
+    return static_cast<PJ_DIRECTION>(-dir);
+}
+
 /*****************************************************************************/
 int proj_angular_input (PJ *P, enum PJ_DIRECTION dir) {
 /******************************************************************************
@@ -72,7 +76,7 @@ int proj_angular_output (PJ *P, enum PJ_DIRECTION dir) {
     operating in direction dir, 0 otherwise.
     dir: {PJ_FWD, PJ_INV}
 ******************************************************************************/
-    return proj_angular_input (P, -dir);
+    return proj_angular_input (P, opposite_direction(dir));
 }
 
 
@@ -126,7 +130,7 @@ double proj_roundtrip (PJ *P, PJ_DIRECTION direction, int n, PJ_COORD *coord) {
     int i;
     PJ_COORD t, org;
 
-    if (0==P)
+    if (nullptr==P)
         return HUGE_VAL;
 
     if (n < 1) {
@@ -142,10 +146,10 @@ double proj_roundtrip (PJ *P, PJ_DIRECTION direction, int n, PJ_COORD *coord) {
     /* now we take n-1 full steps in inverse direction: We are */
     /* out of phase due to the half step already taken */
     for (i = 0;  i < n - 1;  i++)
-        t = proj_trans (P,  direction,  proj_trans (P, -direction, t) );
+        t = proj_trans (P,  direction,  proj_trans (P, opposite_direction(direction), t) );
 
     /* finally, we take the last half-step */
-    t = proj_trans (P, -direction, t);
+    t = proj_trans (P, opposite_direction(direction), t);
 
     /* checking for angular *input* since we do a roundtrip, and end where we begin */
     if (proj_angular_input (P, direction))
@@ -165,10 +169,10 @@ available.
 See also pj_approx_2D_trans and pj_approx_3D_trans in pj_internal.c, which work
 similarly, but prefers the 2D resp. 3D interfaces if available.
 ***************************************************************************************/
-    if (0==P)
+    if (nullptr==P)
         return coord;
     if (P->inverted)
-        direction = -direction;
+        direction = opposite_direction(direction);
 
     switch (direction) {
         case PJ_FWD:
@@ -270,17 +274,17 @@ size_t proj_trans_generic (
     size_t i, nmin;
     double null_broadcast = 0;
 
-    if (0==P)
+    if (nullptr==P)
         return 0;
 
     if (P->inverted)
-        direction = -direction;
+        direction = opposite_direction(direction);
 
     /* ignore lengths of null arrays */
-    if (0==x) nx = 0;
-    if (0==y) ny = 0;
-    if (0==z) nz = 0;
-    if (0==t) nt = 0;
+    if (nullptr==x) nx = 0;
+    if (nullptr==y) ny = 0;
+    if (nullptr==z) nz = 0;
+    if (nullptr==t) nt = 0;
 
     /* and make the nullities point to some real world memory for broadcasting nulls */
     if (0==nx) x = &null_broadcast;
@@ -429,7 +433,7 @@ Returns 1 on success, 0 on failure
     PJ *Q;
     paralist *p;
     int do_cart = 0;
-    if (0==P)
+    if (nullptr==P)
         return 0;
 
     /* Don't recurse when calling proj_create (which calls us back) */
@@ -441,13 +445,13 @@ Returns 1 on success, 0 on failure
 
     /* Don't axisswap if data are already in "enu" order */
     if (p && (0!=strcmp ("enu", p->param))) {
-        char *def = malloc (100+strlen(P->axis));
-        if (0==def)
+        char *def = static_cast<char*>(malloc (100+strlen(P->axis)));
+        if (nullptr==def)
             return 0;
         sprintf (def, "break_cs2cs_recursion     proj=axisswap  axis=%s", P->axis);
         Q = proj_create (P->ctx, def);
         free (def);
-        if (0==Q)
+        if (nullptr==Q)
             return 0;
         P->axisswap = skip_prep_fin(Q);
     }
@@ -456,13 +460,13 @@ Returns 1 on success, 0 on failure
     p = pj_param_exists (P->params, "geoidgrids");
     if (p  &&  strlen (p->param) > strlen ("geoidgrids=")) {
         char *gridnames = p->param + strlen ("geoidgrids=");
-        char *def = malloc (100+strlen(gridnames));
-        if (0==def)
+        char *def = static_cast<char*>(malloc (100+strlen(gridnames)));
+        if (nullptr==def)
             return 0;
         sprintf (def, "break_cs2cs_recursion     proj=vgridshift  grids=%s", gridnames);
         Q = proj_create (P->ctx, def);
         free (def);
-        if (0==Q)
+        if (nullptr==Q)
             return 0;
         P->vgridshift = skip_prep_fin(Q);
     }
@@ -471,19 +475,19 @@ Returns 1 on success, 0 on failure
     p = pj_param_exists (P->params, "nadgrids");
     if (p  &&  strlen (p->param) > strlen ("nadgrids=")) {
         char *gridnames = p->param + strlen ("nadgrids=");
-        char *def = malloc (100+strlen(gridnames));
-        if (0==def)
+        char *def = static_cast<char*>(malloc (100+strlen(gridnames)));
+        if (nullptr==def)
             return 0;
         sprintf (def, "break_cs2cs_recursion     proj=hgridshift  grids=%s", gridnames);
         Q = proj_create (P->ctx, def);
         free (def);
-        if (0==Q)
+        if (nullptr==Q)
             return 0;
         P->hgridshift = skip_prep_fin(Q);
     }
 
     /* We ignore helmert if we have grid shift */
-    p = P->hgridshift ? 0 : pj_param_exists (P->params, "towgs84");
+    p = P->hgridshift ? nullptr : pj_param_exists (P->params, "towgs84");
     while (p) {
         char *def;
         char *s = p->param;
@@ -503,13 +507,13 @@ Returns 1 on success, 0 on failure
         if (n <= 8) /* 8==strlen ("towgs84=") */
             return 0;
 
-        def = malloc (100+n);
-        if (0==def)
+        def = static_cast<char*>(malloc (100+n));
+        if (nullptr==def)
             return 0;
         sprintf (def, "break_cs2cs_recursion     proj=helmert exact %s convention=position_vector", s);
         Q = proj_create (P->ctx, def);
         free(def);
-        if (0==Q)
+        if (nullptr==Q)
             return 0;
         pj_inherit_ellipsoid_def (P, Q);
         P->helmert = skip_prep_fin (Q);
@@ -529,19 +533,19 @@ Returns 1 on success, 0 on failure
             /* TODO later: use C++ ostringstream with imbue(std::locale::classic()) */
             /* to be locale unaware */
             char* next_pos;
-            for (next_pos = def; (next_pos = strchr (next_pos, ',')) != NULL; next_pos++) {
+            for (next_pos = def; (next_pos = strchr (next_pos, ',')) != nullptr; next_pos++) {
                 *next_pos = '.';
             }
         }
         Q = proj_create (P->ctx, def);
-        if (0==Q)
+        if (nullptr==Q)
             return 0;
         P->cart = skip_prep_fin (Q);
 
         if (!P->is_geocent) {
             sprintf (def, "break_cs2cs_recursion     proj=cart  ellps=WGS84");
             Q = proj_create (P->ctx, def);
-            if (0==Q)
+            if (nullptr==Q)
                 return 0;
             P->cart_wgs84 = skip_prep_fin (Q);
         }
@@ -569,15 +573,15 @@ PJ *proj_create (PJ_CONTEXT *ctx, const char *definition) {
     int    ret;
     int    allow_init_epsg;
 
-    if (0==ctx)
+    if (nullptr==ctx)
         ctx = pj_get_default_ctx ();
 
     /* Make a copy that we can manipulate */
     n = strlen (definition);
     args = (char *) malloc (n + 1);
-    if (0==args) {
+    if (nullptr==args) {
         proj_context_errno_set(ctx, ENOMEM);
-        return 0;
+        return nullptr;
     }
     strcpy (args, definition);
 
@@ -585,7 +589,7 @@ PJ *proj_create (PJ_CONTEXT *ctx, const char *definition) {
     if (argc==0) {
         pj_dealloc (args);
         proj_context_errno_set(ctx, PJD_ERR_NO_ARGS);
-        return 0;
+        return nullptr;
     }
 
     argv = pj_trim_argv (argc, args);
@@ -620,18 +624,18 @@ indicator, as in {"+proj=utm", "+zone=32"}, or leave it out, as in {"proj=utm",
     PJ *P;
     const char *c;
 
-    if (0==ctx)
+    if (nullptr==ctx)
         ctx = pj_get_default_ctx ();
-    if (0==argv) {
+    if (nullptr==argv) {
         proj_context_errno_set(ctx, PJD_ERR_NO_ARGS);
-        return 0;
+        return nullptr;
     }
 
     /* We assume that free format is used, and build a full proj_create compatible string */
     c = pj_make_args (argc, argv);
-    if (0==c) {
+    if (nullptr==c) {
         proj_context_errno_set(ctx, ENOMEM);
-        return 0;
+        return nullptr;
     }
 
     P = proj_create (ctx, c);
@@ -642,7 +646,7 @@ indicator, as in {"+proj=utm", "+zone=32"}, or leave it out, as in {"proj=utm",
 
 /** Create an area of use */
 PJ_AREA * proj_area_create(void) {
-    return pj_calloc(1, sizeof(PJ_AREA));
+    return static_cast<PJ_AREA*>(pj_calloc(1, sizeof(PJ_AREA)));
 }
 
 /** Assign a bounding box to an area of use. */
@@ -668,7 +672,7 @@ void proj_area_destroy(PJ_AREA* area) {
 /************************************************************************/
 
 void proj_context_use_proj4_init_rules(PJ_CONTEXT *ctx, int enable) {
-    if( ctx == NULL ) {
+    if( ctx == nullptr ) {
         ctx = pj_get_default_ctx();
     }
     ctx->use_proj4_init_rules = enable;
@@ -693,7 +697,7 @@ static int EQUAL(const char* a, const char* b) {
 int proj_context_get_use_proj4_init_rules(PJ_CONTEXT *ctx, int from_legacy_code_path) {
     const char* val = getenv("PROJ_USE_PROJ4_INIT_RULES");
 
-    if( ctx == NULL ) {
+    if( ctx == nullptr ) {
         ctx = pj_get_default_ctx();
     }
 
@@ -747,26 +751,26 @@ PJ  *proj_create_crs_to_crs (PJ_CONTEXT *ctx, const char *source_crs, const char
     PJ_OBJ_LIST* op_list;
     PJ_OBJ* op;
     const char* proj_string;
-    const char* const optionsProj4Mode[] = { "USE_PROJ4_INIT_RULES=YES", NULL };
+    const char* const optionsProj4Mode[] = { "USE_PROJ4_INIT_RULES=YES", nullptr };
     const char* const* optionsImportCRS =
-        proj_context_get_use_proj4_init_rules(ctx, FALSE) ? optionsProj4Mode : NULL;
+        proj_context_get_use_proj4_init_rules(ctx, FALSE) ? optionsProj4Mode : nullptr;
 
     src = proj_obj_create_from_user_input(ctx, source_crs, optionsImportCRS);
     if( !src ) {
-        return NULL;
+        return nullptr;
     }
 
     dst = proj_obj_create_from_user_input(ctx, target_crs, optionsImportCRS);
     if( !dst ) {
         proj_obj_destroy(src);
-        return NULL;
+        return nullptr;
     }
 
-    operation_ctx = proj_create_operation_factory_context(ctx, NULL);
+    operation_ctx = proj_create_operation_factory_context(ctx, nullptr);
     if( !operation_ctx ) {
         proj_obj_destroy(src);
         proj_obj_destroy(dst);
-        return NULL;
+        return nullptr;
     }
 
     if( area && area->bbox_set ) {
@@ -789,24 +793,24 @@ PJ  *proj_create_crs_to_crs (PJ_CONTEXT *ctx, const char *source_crs, const char
     proj_obj_destroy(dst);
 
     if( !op_list ) {
-        return NULL;
+        return nullptr;
     }
 
     if( proj_obj_list_get_count(op_list) == 0 ) {
         proj_obj_list_destroy(op_list);
-        return NULL;
+        return nullptr;
     }
 
     op = proj_obj_list_get(ctx, op_list, 0);
     proj_obj_list_destroy(op_list);
     if( !op ) {
-        return NULL;
+        return nullptr;
     }
 
-    proj_string = proj_obj_as_proj_string(ctx, op, PJ_PROJ_5, NULL);
+    proj_string = proj_obj_as_proj_string(ctx, op, PJ_PROJ_5, nullptr);
     if( !proj_string) {
         proj_obj_destroy(op);
-        return NULL;
+        return nullptr;
     }
 
     if( proj_string[0] == '\0' ) {
@@ -823,7 +827,7 @@ PJ  *proj_create_crs_to_crs (PJ_CONTEXT *ctx, const char *source_crs, const char
 
 PJ *proj_destroy (PJ *P) {
     pj_free (P);
-    return 0;
+    return nullptr;
 }
 
 /*****************************************************************************/
@@ -840,7 +844,7 @@ int proj_context_errno (PJ_CONTEXT *ctx) {
     Read an error directly from a context, without going through a PJ
     belonging to that context.
 ******************************************************************************/
-    if (0==ctx)
+    if (nullptr==ctx)
         ctx = pj_get_default_ctx();
     return pj_ctx_get_errno (ctx);
 }
@@ -921,15 +925,15 @@ PJ_CONTEXT *proj_context_create (void) {
 
 
 PJ_CONTEXT *proj_context_destroy (PJ_CONTEXT *ctx) {
-    if (0==ctx)
-        return 0;
+    if (nullptr==ctx)
+        return nullptr;
 
     /* Trying to free the default context is a no-op (since it is statically allocated) */
     if (pj_get_default_ctx ()==ctx)
-        return 0;
+        return nullptr;
 
     pj_ctx_free (ctx);
-    return 0;
+    return nullptr;
 }
 
 
@@ -948,32 +952,32 @@ static char *path_append (char *buf, const char *app, size_t *buf_size) {
     char *p;
     size_t len, applen = 0, buflen = 0;
 #ifdef _WIN32
-    char *delim = ";";
+    const char *delim = ";";
 #else
-    char *delim = ":";
+    const char *delim = ":";
 #endif
 
     /* Nothing to do? */
-    if (0 == app)
+    if (nullptr == app)
         return buf;
     applen = strlen (app);
     if (0 == applen)
         return buf;
 
     /* Start checking whether buf is long enough */
-    if (0 != buf)
+    if (nullptr != buf)
         buflen = strlen (buf);
     len = buflen+applen+strlen (delim) + 1;
 
     /* "pj_realloc", so to speak */
     if (*buf_size < len) {
-        p = pj_calloc (2 * len, sizeof (char));
-        if (0==p) {
+        p = static_cast<char*>(pj_calloc (2 * len, sizeof (char)));
+        if (nullptr==p) {
             pj_dealloc (buf);
-            return 0;
+            return nullptr;
         }
         *buf_size = 2 * len;
-        if (buf != 0)
+        if (buf != nullptr)
             strcpy (p, buf);
         pj_dealloc (buf);
         buf = p;
@@ -988,7 +992,7 @@ static char *path_append (char *buf, const char *app, size_t *buf_size) {
 
 static const char *empty = {""};
 static char version[64]  = {""};
-static PJ_INFO info = {0, 0, 0, 0, 0, 0, 0, 0};
+static PJ_INFO info = {0, 0, 0, nullptr, nullptr, nullptr, nullptr, 0};
 static volatile int info_initialized = 0;
 
 /*****************************************************************************/
@@ -1002,7 +1006,7 @@ PJ_INFO proj_info (void) {
     size_t i, n;
 
     size_t  buf_size = 0;
-    char   *buf = 0;
+    char   *buf = nullptr;
 
     pj_acquire_lock ();
 
@@ -1061,7 +1065,7 @@ PJ_PROJ_INFO proj_pj_info(PJ *P) {
     /* proj_create_crs_to_crs in a future version that leverages the EPSG database. */
     pjinfo.accuracy = -1.0;
 
-    if (0==P)
+    if (nullptr==P)
         return pjinfo;
 
     /* projection id */
@@ -1076,7 +1080,7 @@ PJ_PROJ_INFO proj_pj_info(PJ *P) {
         def = P->def_full;
     else
         def = pj_get_def(P, 0); /* pj_get_def takes a non-const PJ pointer */
-    if (0==def)
+    if (nullptr==def)
         pjinfo.definition = empty;
     else
         pjinfo.definition = pj_shrink (def);
@@ -1103,7 +1107,7 @@ PJ_GRID_INFO proj_grid_info(const char *gridname) {
     memset(&grinfo, 0, sizeof(PJ_GRID_INFO));
 
     /* in case the grid wasn't found */
-    if (gridinfo->filename == NULL) {
+    if (gridinfo->filename == nullptr) {
         pj_gridinfo_free(ctx, gridinfo);
         strcpy(grinfo.format, "missing");
         return grinfo;
@@ -1254,7 +1258,7 @@ PJ_FACTORS proj_factors(PJ *P, PJ_COORD lp) {
     PJ_FACTORS factors = {0,0,0,  0,0,0,  0,0,  0,0,0,0};
     struct FACTORS f;
 
-    if (0==P)
+    if (nullptr==P)
         return factors;
 
     if (pj_factors(lp.lp, P, 0.0, &f))
diff --git a/src/Makefile.am b/src/Makefile.am
index f484acd8..e8b9977c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -15,20 +15,20 @@ include_HEADERS = proj.h proj_experimental.h proj_constants.h proj_api.h geodesi
 
 EXTRA_DIST = bin_cct.cmake bin_gie.cmake bin_cs2cs.cmake \
 	bin_geod.cmake bin_nad2bin.cmake bin_proj.cmake bin_projinfo.cmake \
-	lib_proj.cmake CMakeLists.txt bin_geodtest.cmake geodtest.c \
-	pj_wkt1_grammar.y pj_wkt2_grammar.y
+	lib_proj.cmake CMakeLists.txt bin_geodtest.cmake tests/geodtest.cpp \
+	wkt1_grammar.y wkt2_grammar.y apps/emess.h
 
-proj_SOURCES = proj.c gen_cheb.c p_series.c
-projinfo_SOURCES = projinfo.cpp
-cs2cs_SOURCES = cs2cs.cpp gen_cheb.c p_series.c
-cct_SOURCES = cct.c proj_strtod.c proj_strtod.h optargpm.h
-nad2bin_SOURCES = nad2bin.c
-geod_SOURCES = geod.c geod_set.c geod_interface.c geod_interface.h
+proj_SOURCES = apps/proj.cpp apps/gen_cheb.cpp apps/p_series.cpp apps/emess.cpp
+projinfo_SOURCES = apps/projinfo.cpp
+cs2cs_SOURCES = apps/cs2cs.cpp apps/gen_cheb.cpp apps/p_series.cpp apps/emess.cpp
+cct_SOURCES = apps/cct.cpp apps/proj_strtod.cpp apps/proj_strtod.h apps/optargpm.h
+nad2bin_SOURCES = apps/nad2bin.cpp
+geod_SOURCES = apps/geod.cpp apps/geod_set.cpp apps/geod_interface.cpp apps/geod_interface.h apps/emess.cpp
 
-gie_SOURCES = gie.c proj_strtod.c proj_strtod.h optargpm.h
-multistresstest_SOURCES = multistresstest.c
-test228_SOURCES = test228.c
-geodtest_SOURCES = geodtest.c
+gie_SOURCES = apps/gie.cpp apps/proj_strtod.cpp apps/proj_strtod.h apps/optargpm.h
+multistresstest_SOURCES = tests/multistresstest.cpp
+test228_SOURCES = tests/test228.cpp
+geodtest_SOURCES = tests/geodtest.cpp
 
 cct_LDADD = libproj.la
 cs2cs_LDADD = libproj.la
@@ -48,71 +48,181 @@ libproj_la_LDFLAGS = -no-undefined -version-info 14:1:1
 libproj_la_LIBADD = @SQLITE3_LDFLAGS@
 
 libproj_la_SOURCES = \
-	pj_list.h proj_internal.h proj_math.h projects.h\
-	static.cpp util.cpp metadata.cpp common.cpp crs.cpp datum.cpp coordinatesystem.cpp coordinateoperation.cpp io.cpp \
-	internal.cpp factory.cpp c_api.cpp \
-	PJ_aeqd.c PJ_gnom.c PJ_laea.c PJ_mod_ster.c \
-	PJ_nsper.c PJ_nzmg.c PJ_ortho.c PJ_stere.c PJ_sterea.c \
-	PJ_aea.c PJ_bipc.c PJ_bonne.c PJ_eqdc.c PJ_isea.c PJ_ccon.c\
-	PJ_imw_p.c PJ_krovak.c PJ_lcc.c PJ_poly.c \
-	PJ_rpoly.c PJ_sconics.c proj_rouss.c \
-	PJ_cass.c PJ_cc.c PJ_cea.c PJ_eqc.c PJ_gall.c PJ_geoc.c \
-	PJ_labrd.c PJ_lsat.c PJ_misrsom.c PJ_merc.c \
-	PJ_mill.c PJ_ocea.c PJ_omerc.c PJ_somerc.c \
-	PJ_tcc.c PJ_tcea.c PJ_times.c PJ_tmerc.c PJ_tobmerc.c \
-	PJ_airy.c PJ_aitoff.c PJ_august.c PJ_bacon.c \
-	PJ_bertin1953.c PJ_chamb.c PJ_hammer.c PJ_lagrng.c PJ_larr.c \
-	PJ_lask.c PJ_latlong.c PJ_nocol.c PJ_ob_tran.c PJ_oea.c \
-	PJ_tpeqd.c PJ_vandg.c PJ_vandg2.c PJ_vandg4.c \
-	PJ_wag7.c PJ_lcca.c PJ_geos.c proj_etmerc.c \
-	PJ_boggs.c PJ_collg.c PJ_comill.c PJ_crast.c PJ_denoy.c \
-	PJ_eck1.c PJ_eck2.c PJ_eck3.c PJ_eck4.c \
-	PJ_eck5.c PJ_fahey.c PJ_fouc_s.c PJ_gins8.c PJ_gstmerc.c \
-	PJ_gn_sinu.c PJ_goode.c PJ_igh.c PJ_hatano.c PJ_loxim.c \
-	PJ_mbt_fps.c PJ_mbtfpp.c PJ_mbtfpq.c PJ_moll.c \
-	PJ_nell.c PJ_nell_h.c PJ_patterson.c PJ_putp2.c PJ_putp3.c \
-	PJ_putp4p.c PJ_putp5.c PJ_putp6.c PJ_qsc.c PJ_robin.c \
-	PJ_sch.c PJ_sts.c PJ_urm5.c PJ_urmfps.c PJ_wag2.c \
-	PJ_wag3.c PJ_wink1.c PJ_wink2.c pj_geocent.c \
-	aasincos.c adjlon.c bch2bps.c bchgen.c \
-	biveval.c dmstor.c mk_cheby.c pj_auth.c \
-	pj_deriv.c pj_ell_set.c pj_ellps.c pj_errno.c \
-	pj_factors.c pj_fwd.c pj_init.c pj_inv.c \
-	pj_list.c pj_malloc.c pj_mlfn.c pj_msfn.c proj_mdist.c \
-	pj_open_lib.c pj_param.c pj_phi2.c pj_pr_list.c \
-	pj_qsfn.c pj_strerrno.c \
-	pj_tsfn.c pj_units.c pj_ctx.c pj_log.c pj_zpoly1.c rtodms.c \
-	vector1.c pj_release.c pj_gauss.c \
-	PJ_healpix.c PJ_natearth.c PJ_natearth2.c PJ_calcofi.c pj_fileapi.c \
-	PJ_eqearth.c \
+	pj_list.h proj_internal.h proj_math.h projects.h \
 	\
-	pj_gc_reader.c pj_gridcatalog.c \
-	nad_cvt.c nad_init.c nad_intr.c emess.c emess.h \
-	pj_apply_gridshift.c pj_datums.c pj_datum_set.c pj_transform.c \
-	geocent.c geocent.h pj_utils.c pj_gridinfo.c pj_gridlist.c \
-	jniproj.c pj_mutex.c pj_initcache.c pj_apply_vgridshift.c geodesic.c \
-	pj_strtod.c pj_math.c\
+	iso19111/static.cpp \
+	iso19111/util.cpp \
+	iso19111/metadata.cpp \
+	iso19111/common.cpp \
+	iso19111/crs.cpp \
+	iso19111/datum.cpp \
+	iso19111/coordinatesystem.cpp \
+	iso19111/coordinateoperation.cpp \
+	iso19111/io.cpp \
+	iso19111/internal.cpp \
+	iso19111/factory.cpp \
+	iso19111/c_api.cpp \
 	\
-	proj_4D_api.c PJ_cart.c PJ_pipeline.c PJ_horner.c PJ_helmert.c \
-	PJ_vgridshift.c PJ_hgridshift.c PJ_unitconvert.c PJ_molodensky.c \
-	PJ_deformation.c pj_internal.c PJ_axisswap.c PJ_affine.c \
-	pj_wkt_parser.hpp pj_wkt_parser.cpp \
-	pj_wkt1_parser.h pj_wkt1_parser.cpp \
-	pj_wkt1_generated_parser.h pj_wkt1_generated_parser.c \
-	pj_wkt2_parser.h pj_wkt2_parser.cpp \
-	pj_wkt2_generated_parser.h pj_wkt2_generated_parser.c
+	projections/aeqd.cpp \
+	projections/gnom.cpp \
+	projections/laea.cpp \
+	projections/mod_ster.cpp \
+	projections/nsper.cpp \
+	projections/nzmg.cpp \
+	projections/ortho.cpp \
+	projections/stere.cpp \
+	projections/sterea.cpp \
+	projections/aea.cpp \
+	projections/bipc.cpp \
+	projections/bonne.cpp \
+	projections/eqdc.cpp \
+	projections/isea.cpp \
+	projections/ccon.cpp \
+	projections/imw_p.cpp \
+	projections/krovak.cpp \
+	projections/lcc.cpp \
+	projections/poly.cpp \
+	projections/rpoly.cpp \
+	projections/sconics.cpp \
+	projections/rouss.cpp \
+	projections/cass.cpp \
+	projections/cc.cpp \
+	projections/cea.cpp \
+	projections/eqc.cpp \
+	projections/gall.cpp \
+	projections/labrd.cpp \
+	projections/lsat.cpp \
+	projections/misrsom.cpp \
+	projections/merc.cpp \
+	projections/mill.cpp \
+	projections/ocea.cpp \
+	projections/omerc.cpp \
+	projections/somerc.cpp \
+	projections/tcc.cpp \
+	projections/tcea.cpp \
+	projections/times.cpp \
+	projections/tmerc.cpp \
+	projections/tobmerc.cpp \
+	projections/airy.cpp \
+	projections/aitoff.cpp \
+	projections/august.cpp \
+	projections/bacon.cpp \
+	projections/bertin1953.cpp \
+	projections/chamb.cpp \
+	projections/hammer.cpp \
+	projections/lagrng.cpp \
+	projections/larr.cpp \
+	projections/lask.cpp \
+	projections/latlong.cpp \
+	projections/nicol.cpp \
+	projections/ob_tran.cpp \
+	projections/oea.cpp \
+	projections/tpeqd.cpp \
+	projections/vandg.cpp \
+	projections/vandg2.cpp \
+	projections/vandg4.cpp \
+	projections/wag7.cpp \
+	projections/lcca.cpp \
+	projections/geos.cpp \
+	projections/etmerc.cpp \
+	projections/boggs.cpp \
+	projections/collg.cpp \
+	projections/comill.cpp \
+	projections/crast.cpp \
+	projections/denoy.cpp \
+	projections/eck1.cpp \
+	projections/eck2.cpp \
+	projections/eck3.cpp \
+	projections/eck4.cpp \
+	projections/eck5.cpp \
+	projections/fahey.cpp \
+	projections/fouc_s.cpp \
+	projections/gins8.cpp \
+	projections/gstmerc.cpp \
+	projections/gn_sinu.cpp \
+	projections/goode.cpp \
+	projections/igh.cpp \
+	projections/hatano.cpp \
+	projections/loxim.cpp \
+	projections/mbt_fps.cpp \
+	projections/mbtfpp.cpp \
+	projections/mbtfpq.cpp \
+	projections/moll.cpp \
+	projections/nell.cpp \
+	projections/nell_h.cpp \
+	projections/patterson.cpp \
+	projections/putp2.cpp \
+	projections/putp3.cpp \
+	projections/putp4p.cpp \
+	projections/putp5.cpp \
+	projections/putp6.cpp \
+	projections/qsc.cpp \
+	projections/robin.cpp \
+	projections/sch.cpp \
+	projections/sts.cpp \
+	projections/urm5.cpp \
+	projections/urmfps.cpp \
+	projections/wag2.cpp \
+	projections/wag3.cpp \
+	projections/wink1.cpp \
+	projections/wink2.cpp \
+	projections/healpix.cpp \
+	projections/natearth.cpp \
+	projections/natearth2.cpp \
+	projections/calcofi.cpp \
+	projections/eqearth.cpp \
+	\
+	conversions/axisswap.cpp \
+	conversions/cart.cpp \
+	conversions/geoc.cpp \
+	conversions/geocent.cpp \
+	conversions/unitconvert.cpp \
+	\
+	transformations/affine.cpp \
+	transformations/deformation.cpp \
+	transformations/helmert.cpp \
+	transformations/hgridshift.cpp \
+	transformations/horner.cpp \
+	transformations/molodensky.cpp \
+	transformations/vgridshift.cpp \
+	\
+	aasincos.cpp adjlon.cpp bch2bps.cpp bchgen.cpp \
+	biveval.cpp dmstor.cpp mk_cheby.cpp auth.cpp \
+	deriv.cpp ell_set.cpp ellps.cpp errno.cpp \
+	factors.cpp fwd.cpp init.cpp inv.cpp \
+	list.cpp malloc.cpp mlfn.cpp msfn.cpp proj_mdist.cpp \
+	open_lib.cpp param.cpp phi2.cpp pr_list.cpp \
+	qsfn.cpp strerrno.cpp \
+	tsfn.cpp units.cpp ctx.cpp log.cpp zpoly1.cpp rtodms.cpp \
+	vector1.cpp release.cpp gauss.cpp \
+	fileapi.cpp \
+	\
+	gc_reader.cpp gridcatalog.cpp \
+	nad_cvt.cpp nad_init.cpp nad_intr.cpp \
+	apply_gridshift.cpp datums.cpp datum_set.cpp transform.cpp \
+	geocent.cpp geocent.h utils.cpp gridinfo.cpp gridlist.cpp \
+	jniproj.cpp mutex.cpp initcache.cpp apply_vgridshift.cpp geodesic.c \
+	strtod.cpp math.cpp \
+	\
+	4D_api.cpp pipeline.cpp \
+	internal.cpp \
+	wkt_parser.hpp wkt_parser.cpp \
+	wkt1_parser.h wkt1_parser.cpp \
+	wkt1_generated_parser.h wkt1_generated_parser.c \
+	wkt2_parser.h wkt2_parser.cpp \
+	wkt2_generated_parser.h wkt2_generated_parser.c
 
 
 # The sed hack is to please MSVC
 wkt1_parser:
-	bison --no-lines -d  -p pj_wkt1_ -o$(top_srcdir)/src/pj_wkt1_generated_parser.c $(top_srcdir)/src/pj_wkt1_grammar.y
-	sed "s/\*yyssp = yystate/\*yyssp = (yytype_int16)yystate/" < $(top_srcdir)/src/pj_wkt1_generated_parser.c | sed "s/yyerrorlab:/#if 0\nyyerrorlab:/" | sed "s/yyerrlab1:/#endif\nyyerrlab1:/" | sed "s/for (yylen = 0; yystr\[yylen\]; yylen++)/for (yylen = 0; yystr \&\& yystr\[yylen\]; yylen++)/"  > $(top_srcdir)/src/pj_wkt1_generated_parser.c.tmp
-	mv $(top_srcdir)/src/pj_wkt1_generated_parser.c.tmp $(top_srcdir)/src/pj_wkt1_generated_parser.c
+	bison --no-lines -d  -p pj_wkt1_ -o$(top_srcdir)/src/wkt1_generated_parser.c $(top_srcdir)/src/wkt1_grammar.y
+	sed "s/\*yyssp = yystate/\*yyssp = (yytype_int16)yystate/" < $(top_srcdir)/src/wkt1_generated_parser.c | sed "s/yyerrorlab:/#if 0\nyyerrorlab:/" | sed "s/yyerrlab1:/#endif\nyyerrlab1:/" | sed "s/for (yylen = 0; yystr\[yylen\]; yylen++)/for (yylen = 0; yystr \&\& yystr\[yylen\]; yylen++)/"  > $(top_srcdir)/src/wkt1_generated_parser.c.tmp
+	mv $(top_srcdir)/src/wkt1_generated_parser.c.tmp $(top_srcdir)/src/wkt1_generated_parser.c
 
 wkt2_parser:
-	bison --no-lines -d  -p pj_wkt2_ -o$(top_srcdir)/src/pj_wkt2_generated_parser.c $(top_srcdir)/src/pj_wkt2_grammar.y
-	sed "s/\*yyssp = yystate/\*yyssp = (yytype_int16)yystate/" < $(top_srcdir)/src/pj_wkt2_generated_parser.c | sed "s/yyerrorlab:/#if 0\nyyerrorlab:/" | sed "s/yyerrlab1:/#endif\nyyerrlab1:/" | sed "s/for (yylen = 0; yystr\[yylen\]; yylen++)/for (yylen = 0; yystr \&\& yystr\[yylen\]; yylen++)/"  > $(top_srcdir)/src/pj_wkt2_generated_parser.c.tmp
-	mv $(top_srcdir)/src/pj_wkt2_generated_parser.c.tmp $(top_srcdir)/src/pj_wkt2_generated_parser.c
+	bison --no-lines -d  -p pj_wkt2_ -o$(top_srcdir)/src/wkt2_generated_parser.c $(top_srcdir)/src/wkt2_grammar.y
+	sed "s/\*yyssp = yystate/\*yyssp = (yytype_int16)yystate/" < $(top_srcdir)/src/wkt2_generated_parser.c | sed "s/yyerrorlab:/#if 0\nyyerrorlab:/" | sed "s/yyerrlab1:/#endif\nyyerrlab1:/" | sed "s/for (yylen = 0; yystr\[yylen\]; yylen++)/for (yylen = 0; yystr \&\& yystr\[yylen\]; yylen++)/"  > $(top_srcdir)/src/wkt2_generated_parser.c.tmp
+	mv $(top_srcdir)/src/wkt2_generated_parser.c.tmp $(top_srcdir)/src/wkt2_generated_parser.c
 
 
 install-exec-local: install-binPROGRAMS
diff --git a/src/aasincos.c b/src/aasincos.cpp
index 4f9ea25f..4f9ea25f 100644
--- a/src/aasincos.c
+++ b/src/aasincos.cpp
diff --git a/src/adjlon.c b/src/adjlon.cpp
index 784a90aa..784a90aa 100644
--- a/src/adjlon.c
+++ b/src/adjlon.cpp
diff --git a/src/pj_apply_gridshift.c b/src/apply_gridshift.cpp
index 45ce5c8e..4c8115cc 100644
--- a/src/pj_apply_gridshift.c
+++ b/src/apply_gridshift.cpp
@@ -57,7 +57,7 @@ int pj_apply_gridshift( projCtx ctx, const char *nadgrids, int inverse,
 
     gridlist = pj_gridlist_from_nadgrids( ctx, nadgrids, &grid_count );
 
-    if( gridlist == NULL || grid_count == 0 )
+    if( gridlist == nullptr || grid_count == 0 )
         return ctx->last_errno;
 
     ret = pj_apply_gridshift_3( ctx, gridlist, grid_count, inverse,
@@ -86,18 +86,18 @@ int pj_apply_gridshift_2( PJ *defn, int inverse,
                           double *x, double *y, double *z )
 
 {
-    if( defn->catalog_name != NULL )
+    if( defn->catalog_name != nullptr )
         return pj_gc_apply_gridshift( defn, inverse, point_count, point_offset,
                                       x, y, z );
 
-    if( defn->gridlist == NULL )
+    if( defn->gridlist == nullptr )
     {
         defn->gridlist =
             pj_gridlist_from_nadgrids( pj_get_ctx( defn ),
                                        pj_param(defn->ctx, defn->params,"snadgrids").s,
                                        &(defn->gridlist_count) );
 
-        if( defn->gridlist == NULL || defn->gridlist_count == 0 )
+        if( defn->gridlist == nullptr || defn->gridlist_count == 0 )
             return defn->ctx->last_errno;
     }
 
@@ -135,7 +135,7 @@ static struct CTABLE* find_ctable(projCtx ctx, LP input, int grid_count, PJ_GRID
         {
             PJ_GRIDINFO *child;
 
-            for( child = gi->child; child != NULL; child = child->next )
+            for( child = gi->child; child != nullptr; child = child->next )
             {
                 struct CTABLE *ct1 = child->ct;
                 epsilon = (fabs(ct1->del.phi)+fabs(ct1->del.lam))/10000.0;
@@ -150,24 +150,24 @@ static struct CTABLE* find_ctable(projCtx ctx, LP input, int grid_count, PJ_GRID
             }
 
             /* If we didn't find a child then nothing more to do */
-            if( child == NULL ) break;
+            if( child == nullptr ) break;
 
             /* Otherwise use the child, first checking it's children */
             gi = child;
             ct = child->ct;
         }
         /* load the grid shift info if we don't have it. */
-        if( ct->cvs == NULL) {
+        if( ct->cvs == nullptr) {
             if (!pj_gridinfo_load( ctx, gi ) ) {
                 pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-                return NULL;
+                return nullptr;
             }
         }
         /* if we get this far we have found a suitable grid */
         return ct;
     }
 
-    return NULL;
+    return nullptr;
 }
 
 /************************************************************************/
@@ -185,7 +185,7 @@ int pj_apply_gridshift_3( projCtx ctx, PJ_GRIDINFO **gridlist, int gridlist_coun
     static int debug_count = 0;
     (void) z;
 
-    if( gridlist== NULL || gridlist_count == 0 )
+    if( gridlist== nullptr || gridlist_count == 0 )
     {
         pj_ctx_set_errno(ctx, PJD_ERR_FAILED_TO_LOAD_GRID);
         return PJD_ERR_FAILED_TO_LOAD_GRID;
@@ -205,7 +205,7 @@ int pj_apply_gridshift_3( projCtx ctx, PJ_GRIDINFO **gridlist, int gridlist_coun
         output.lam = HUGE_VAL;
 
         ct = find_ctable(ctx, input, gridlist_count, gridlist);
-        if( ct != NULL )
+        if( ct != nullptr )
         {
             output = nad_cvt( input, inverse, ct );
 
@@ -280,14 +280,14 @@ int proj_hgrid_init(PJ* P, const char *grids) {
     char *sgrids = (char *) pj_malloc( (strlen(grids)+1+1) *sizeof(char) );
     sprintf(sgrids, "%s%s", "s", grids);
 
-    if (P->gridlist == NULL) {
+    if (P->gridlist == nullptr) {
         P->gridlist = pj_gridlist_from_nadgrids(
             P->ctx,
             pj_param(P->ctx, P->params, sgrids).s,
             &(P->gridlist_count)
         );
 
-        if( P->gridlist == NULL || P->gridlist_count == 0 ) {
+        if( P->gridlist == nullptr || P->gridlist_count == 0 ) {
             pj_dealloc(sgrids);
             return 0;
         }
@@ -311,7 +311,7 @@ LP proj_hgrid_value(PJ *P, LP lp) {
     LP out = proj_coord_error().lp;
 
     ct = find_ctable(P->ctx, lp, P->gridlist_count, P->gridlist);
-    if (ct == 0) {
+    if (ct == nullptr) {
         pj_ctx_set_errno( P->ctx, PJD_ERR_GRID_AREA);
         return out;
     }
@@ -340,7 +340,7 @@ LP proj_hgrid_apply(PJ *P, LP lp, PJ_DIRECTION direction) {
 
     ct = find_ctable(P->ctx, lp, P->gridlist_count, P->gridlist);
 
-    if (ct == NULL || ct->cvs == NULL) {
+    if (ct == nullptr || ct->cvs == nullptr) {
         pj_ctx_set_errno( P->ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
         return out;
     }
diff --git a/src/pj_apply_vgridshift.c b/src/apply_vgridshift.cpp
index c1344951..1facfed6 100644
--- a/src/pj_apply_vgridshift.c
+++ b/src/apply_vgridshift.cpp
@@ -70,11 +70,11 @@ static double read_vgrid_value( PJ *defn, LP input, int *gridlist_count_p, PJ_GR
             continue;
 
         /* If we have child nodes, check to see if any of them apply. */
-        while( gi->child != NULL )
+        while( gi->child != nullptr )
         {
             PJ_GRIDINFO *child;
 
-            for( child = gi->child; child != NULL; child = child->next )
+            for( child = gi->child; child != nullptr; child = child->next )
             {
                 struct CTABLE *ct1 = child->ct;
 
@@ -87,7 +87,7 @@ static double read_vgrid_value( PJ *defn, LP input, int *gridlist_count_p, PJ_GR
             }
 
             /* we didn't find a more refined child node to use, so go with current grid */
-            if( child == NULL )
+            if( child == nullptr )
             {
                 break;
             }
@@ -98,7 +98,7 @@ static double read_vgrid_value( PJ *defn, LP input, int *gridlist_count_p, PJ_GR
         }
 
         /* load the grid shift info if we don't have it. */
-        if( ct->cvs == NULL && !pj_gridinfo_load( pj_get_ctx(defn), gi ) )
+        if( ct->cvs == nullptr && !pj_gridinfo_load( pj_get_ctx(defn), gi ) )
         {
             pj_ctx_set_errno( defn->ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
             return PJD_ERR_FAILED_TO_LOAD_GRID;
@@ -189,14 +189,14 @@ int pj_apply_vgridshift( PJ *defn, const char *listname,
     PJ_GRIDINFO **tables;
     struct CTABLE ct;
 
-    if( *gridlist_p == NULL )
+    if( *gridlist_p == nullptr )
     {
         *gridlist_p =
             pj_gridlist_from_nadgrids( pj_get_ctx(defn),
                                        pj_param(defn->ctx,defn->params,listname).s,
                                        gridlist_count_p );
 
-        if( *gridlist_p == NULL || *gridlist_count_p == 0 )
+        if( *gridlist_p == nullptr || *gridlist_count_p == 0 )
             return defn->ctx->last_errno;
     }
 
@@ -288,14 +288,14 @@ int proj_vgrid_init(PJ* P, const char *grids) {
     char *sgrids = (char *) pj_malloc( (strlen(grids)+1+1) *sizeof(char) );
     sprintf(sgrids, "%s%s", "s", grids);
 
-    if (P->vgridlist_geoid == NULL) {
+    if (P->vgridlist_geoid == nullptr) {
         P->vgridlist_geoid = pj_gridlist_from_nadgrids(
             P->ctx,
             pj_param(P->ctx, P->params, sgrids).s,
             &(P->vgridlist_geoid_count)
         );
 
-        if( P->vgridlist_geoid == NULL || P->vgridlist_geoid_count == 0 ) {
+        if( P->vgridlist_geoid == nullptr || P->vgridlist_geoid_count == 0 ) {
             pj_dealloc(sgrids);
             return 0;
         }
diff --git a/src/cct.c b/src/apps/cct.cpp
index 54734b98..046257da 100644
--- a/src/cct.c
+++ b/src/apps/cct.cpp
@@ -187,7 +187,7 @@ static void print(PJ_LOG_LEVEL log_level, const char *fmt, ...) {
     va_start( args, fmt );
 
     msg_buf = (char *) malloc(100000);
-    if( msg_buf == NULL ) {
+    if( msg_buf == nullptr ) {
         va_end( args );
         return;
     }
@@ -211,12 +211,12 @@ int main(int argc, char **argv) {
     char *comment;
     char *comment_delimiter;
     char *buf;
-    int i, nfields = 4, direction = 1, skip_lines = 0, verbose;
+    int i, nfields = 4, skip_lines = 0, verbose;
     double fixed_z = HUGE_VAL, fixed_time = HUGE_VAL;
     int decimals_angles = 10;
     int decimals_distances = 4;
     int columns_xyzt[] = {1, 2, 3, 4};
-    const char *longflags[]  = {"v=verbose", "h=help", "I=inverse", "version", 0};
+    const char *longflags[]  = {"v=verbose", "h=help", "I=inverse", "version", nullptr};
     const char *longkeys[]   = {
         "o=output",
         "c=columns",
@@ -224,12 +224,12 @@ int main(int argc, char **argv) {
         "z=height",
         "t=time",
         "s=skip-lines",
-        0};
+        nullptr};
 
     fout = stdout;
 
     o = opt_parse (argc, argv, "hvI", "cdozts", longflags, longkeys);
-    if (0==o)
+    if (nullptr==o)
         return 0;
 
     if (opt_given (o, "h") || argc==1) {
@@ -237,10 +237,10 @@ int main(int argc, char **argv) {
         return 0;
     }
 
-    direction = opt_given (o, "I")? -1: 1;
+    PJ_DIRECTION direction = opt_given (o, "I")? PJ_INV: PJ_FWD;
 
     verbose   = MIN(opt_given (o, "v"), 3); /* log level can't be larger than 3 */
-    proj_log_level (PJ_DEFAULT_CTX, verbose);
+    proj_log_level (PJ_DEFAULT_CTX, static_cast<PJ_LOG_LEVEL>(verbose));
     proj_log_func  (PJ_DEFAULT_CTX, (void *) fout, logger);
 
     if (opt_given (o, "version")) {
@@ -250,7 +250,7 @@ int main(int argc, char **argv) {
 
     if (opt_given (o, "o"))
         fout = fopen (opt_arg (o, "output"), "wt");
-    if (0==fout) {
+    if (nullptr==fout) {
         print (PJ_LOG_ERROR, "%s: Cannot open '%s' for output\n", o->progname, opt_arg (o, "output"));
         free (o);
         return 1;
@@ -296,8 +296,8 @@ int main(int argc, char **argv) {
     }
 
     /* Setup transformation */
-    P = proj_create_argv (0, o->pargc, o->pargv);
-    if ((0==P) || (0==o->pargc)) {
+    P = proj_create_argv (nullptr, o->pargc, o->pargv);
+    if ((nullptr==P) || (0==o->pargc)) {
         print (PJ_LOG_ERROR, "%s: Bad transformation arguments - (%s)\n    '%s -h' for help\n",
                  o->progname, pj_strerrno (proj_errno(P)), o->progname);
         free (o);
@@ -309,7 +309,7 @@ int main(int argc, char **argv) {
     info = proj_pj_info (P);
     print (PJ_LOG_TRACE, "Final: %s argc=%d pargc=%d\n", info.definition, argc, o->pargc);
 
-    if (direction==-1) {
+    if (direction== PJ_INV) {
         /* fail if an inverse operation is not available */
         if (!info.has_inverse) {
             print (PJ_LOG_ERROR, "Inverse operation not available\n");
@@ -320,11 +320,11 @@ int main(int argc, char **argv) {
         /* We have no API call for inverting an operation, so we brute force it. */
         P->inverted = !(P->inverted);
     }
-    direction = 1;
+    direction = PJ_FWD;
 
     /* Allocate input buffer */
-    buf = calloc (1, 10000);
-    if (0==buf) {
+    buf = static_cast<char*>(calloc (1, 10000));
+    if (nullptr==buf) {
         print (PJ_LOG_ERROR, "%s: Out of memory\n", o->progname);
         pj_free (P);
         free (o);
@@ -340,7 +340,7 @@ int main(int argc, char **argv) {
         void *ret = fgets (buf, 10000, o->input);
         char *c = column (buf, 1);
         opt_eof_handler (o);
-        if (0==ret) {
+        if (nullptr==ret) {
             print (PJ_LOG_ERROR, "Read error in record %d\n", (int) o->record_index);
             continue;
         }
diff --git a/src/cs2cs.cpp b/src/apps/cs2cs.cpp
index f63bedcc..f63bedcc 100644
--- a/src/cs2cs.cpp
+++ b/src/apps/cs2cs.cpp
diff --git a/src/emess.c b/src/apps/emess.cpp
index eb2ac9d6..144e9e23 100644
--- a/src/emess.c
+++ b/src/apps/emess.cpp
@@ -29,11 +29,11 @@ emess(int code, const char *fmt, ...) {
 
 	va_start(args, fmt);
 	/* prefix program name, if given */
-	if (fmt != NULL)
+	if (fmt != nullptr)
 		(void)fprintf(stderr,"%s\n<%s>: ",pj_get_release(),
                               emess_dat.Prog_name);
 	/* print file name and line, if given */
-	if (emess_dat.File_name != NULL && *emess_dat.File_name) {
+	if (emess_dat.File_name != nullptr && *emess_dat.File_name) {
 		(void)fprintf(stderr,"while processing file: %s", emess_dat.File_name);
 		if (emess_dat.File_line > 0)
 			(void)fprintf(stderr,", line %d\n", emess_dat.File_line);
diff --git a/src/emess.h b/src/apps/emess.h
index cb6b38f4..4c6f6783 100644
--- a/src/emess.h
+++ b/src/apps/emess.h
@@ -2,10 +2,6 @@
 #ifndef EMESS_H
 #define EMESS_H
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 struct EMESS {
 	char	*File_name,	/* input file name */
 			*Prog_name;	/* name of program */
@@ -15,7 +11,7 @@ struct EMESS {
 
 #ifdef EMESS_ROUTINE	/* use type */
 /* for emess procedure */
-struct EMESS PROJ_DLL emess_dat = { (char *)0, (char *)0, 0 };
+struct EMESS emess_dat = { nullptr, nullptr, 0 };
 
 #ifdef sun /* Archaic SunOs 4.1.1, etc. */
 extern char *sys_errlist[];
@@ -24,14 +20,10 @@ extern char *sys_errlist[];
 
 #else	/* for for calling procedures */
 
-extern struct EMESS PROJ_DLL emess_dat;
+extern struct EMESS emess_dat;
 
 #endif /* use type */
 
-void PROJ_DLL emess(int, const char *, ...);
-
-#ifdef __cplusplus
-}
-#endif
+void emess(int, const char *, ...);
 
 #endif /* end EMESS_H */
diff --git a/src/gen_cheb.c b/src/apps/gen_cheb.cpp
index ab16b409..4ba514d4 100644
--- a/src/gen_cheb.c
+++ b/src/apps/gen_cheb.cpp
@@ -9,12 +9,40 @@
 #define COEF_LINE_MAX 50
 #endif
 
+static double strtod_type_safe(const char *s, const char ** endptr)
+{
+    char* l_endptr = nullptr;
+    double ret= strtod(s, &l_endptr);
+    if( endptr )
+        *endptr = static_cast<const char*>(l_endptr);
+    return ret;
+}
+
+static double dmstor_type_safe(const char *s, const char ** endptr)
+{
+    char* l_endptr = nullptr;
+    double ret= dmstor(s, &l_endptr);
+    if( endptr )
+        *endptr = static_cast<const char*>(l_endptr);
+    return ret;
+}
+
+static long strtol_type_safe(const char *s, const char ** endptr, int base)
+{
+    char* l_endptr = nullptr;
+    long ret = strtol(s, &l_endptr, base);
+    if( endptr )
+        *endptr = static_cast<const char*>(l_endptr);
+    return ret;
+}
+
+
 /* FIXME: put the declaration in a header. Also used in proj.c */
-void gen_cheb(int inverse, projUV (*proj)(projUV), char *s, PJ *P,
+void gen_cheb(int inverse, projUV (*proj)(projUV), const char *s, PJ *P,
               int iargc, char **iargv);
 extern void p_series(Tseries *, FILE *, char *);
 
-void gen_cheb(int inverse, projUV (*proj)(projUV), char *s, PJ *P,
+void gen_cheb(int inverse, projUV (*proj)(projUV), const char *s, PJ *P,
               int iargc, char **iargv) {
 	long NU = 15, NV = 15;
 	int errin = 0, pwr;
@@ -22,18 +50,18 @@ void gen_cheb(int inverse, projUV (*proj)(projUV), char *s, PJ *P,
 	char *arg, fmt[32];
 	projUV low, upp, resid;
 	Tseries *F;
-	double (*input)(const char *, char **);
+	double (*input)(const char *, const char **);
 
-	input = inverse ? strtod : dmstor;
+	input = inverse ? strtod_type_safe : dmstor_type_safe;
 	if (*s) low.u = input(s, &s); else { low.u = 0; ++errin; }
 	if (*s == ',') upp.u = input(s+1, &s); else { upp.u = 0; ++errin; }
 	if (*s == ',') low.v = input(s+1, &s); else { low.v = 0; ++errin; }
 	if (*s == ',') upp.v = input(s+1, &s); else { upp.v = 0; ++errin; }
 	if (errin)
 		emess(16,"null or absent -T parameters");
-	if (*s == ',') if (*++s != ',') res = strtol(s, &s, 10);
-	if (*s == ',') if (*++s != ',') NU = strtol(s, &s, 10);
-	if (*s == ',') if (*++s != ',') NV = strtol(s, &s, 10);
+	if (*s == ',') if (*++s != ',') res = strtol_type_safe(s, &s, 10);
+	if (*s == ',') if (*++s != ',') NU = strtol_type_safe(s, &s, 10);
+	if (*s == ',') if (*++s != ',') NV = strtol_type_safe(s, &s, 10);
 	pwr = s && *s && !strcmp(s, ",P");
 	(void)printf("#proj_%s\n#    run-line:\n",
 		pwr ? "Power" : "Chebyshev");
diff --git a/src/geod.c b/src/apps/geod.cpp
index bb52818e..7b6367c6 100644
--- a/src/geod.c
+++ b/src/apps/geod.cpp
@@ -16,12 +16,14 @@ fullout = 0,	/* output full set of geodesic values */
 tag = '#',	/* beginning of line tag character */
 pos_azi = 0,	/* output azimuths as positive values */
 inverse = 0;	/* != 0 then inverse geodesic */
-	static char
-*oform = (char *)0,	/* output format for decimal degrees */
-*osform = "%.3f",	/* output format for S */
-pline[50],		/* work string */
-*usage =
+
+static const char *oform = nullptr; /* output format for decimal degrees */
+static const char *osform = "%.3f"; /* output format for S */
+
+static char pline[50];              /* work string */
+static const char *usage =
 "%s\nusage: %s [ -afFIlptwW [args] ] [ +opts[=arg] ] [ files ]\n";
+
 	static void
 printLL(double p, double l) {
 	if (oform) {
@@ -133,7 +135,7 @@ int main(int argc, char **argv) {
 	FILE *fid;
 	static int eargc = 0, c;
 
-	if ((emess_dat.Prog_name = strrchr(*argv,'/')) != NULL) ++emess_dat.Prog_name;
+	if ((emess_dat.Prog_name = strrchr(*argv,'/')) != nullptr) ++emess_dat.Prog_name;
 	else emess_dat.Prog_name = *argv;
 	inverse = ! strncmp(emess_dat.Prog_name, "inv", 3);
 	if (argc <= 1 ) {
@@ -146,7 +148,7 @@ int main(int argc, char **argv) {
 		if(**++argv == '-') for(arg = *argv;;) {
 			switch(*++arg) {
 			case '\0': /* position of "stdin" */
-				if (arg[-1] == '-') eargv[eargc++] = "-";
+				if (arg[-1] == '-') eargv[eargc++] = const_cast<char*>("-");
 				break;
 			case 'a': /* output full set of values */
 				fullout = 1;
@@ -217,13 +219,13 @@ noargument:		   emess(1,"missing argument for -%c",*arg);
 		do_geod();
 	else { /* process input file list */
 		if (eargc == 0) /* if no specific files force sysin */
-			eargv[eargc++] = "-";
+			eargv[eargc++] = const_cast<char*>("-");
 		for ( ; eargc-- ; ++eargv) {
 			if (**eargv == '-') {
 				fid = stdin;
-				emess_dat.File_name = "<stdin>";
+				emess_dat.File_name = const_cast<char*>("<stdin>");
 			} else {
-				if ((fid = fopen(*eargv, "r")) == NULL) {
+				if ((fid = fopen(*eargv, "r")) == nullptr) {
 					emess(-2, *eargv, "input file");
 					continue;
 				}
@@ -232,7 +234,7 @@ noargument:		   emess(1,"missing argument for -%c",*arg);
 			emess_dat.File_line = 0;
 			process(fid);
 			(void)fclose(fid);
-			emess_dat.File_name = (char *)0;
+			emess_dat.File_name = (char *)nullptr;
 		}
 	}
 	exit(0); /* normal completion */
diff --git a/src/geod_interface.c b/src/apps/geod_interface.cpp
index a30377ac..a30377ac 100644
--- a/src/geod_interface.c
+++ b/src/apps/geod_interface.cpp
diff --git a/src/geod_interface.h b/src/apps/geod_interface.h
index 255d505a..255d505a 100644
--- a/src/geod_interface.h
+++ b/src/apps/geod_interface.h
diff --git a/src/geod_set.c b/src/apps/geod_set.cpp
index b5bd0667..b9e9c42f 100644
--- a/src/geod_set.c
+++ b/src/apps/geod_set.cpp
@@ -11,7 +11,7 @@
 
 	void
 geod_set(int argc, char **argv) {
-	paralist *start = 0, *curr;
+	paralist *start = nullptr, *curr;
 	double es;
 	char *name;
 	int i;
@@ -22,7 +22,7 @@ geod_set(int argc, char **argv) {
 	start = curr = pj_mkparam(argv[0]);
 	if (!curr)
 		emess(1, "memory allocation failed");
-	for (i = 1; curr != 0 && i < argc; ++i) {
+	for (i = 1; curr != nullptr && i < argc; ++i) {
 		curr->next = pj_mkparam(argv[i]);
 		if (!curr->next)
 			emess(1, "memory allocation failed");
@@ -31,7 +31,7 @@ geod_set(int argc, char **argv) {
 	/* set elliptical parameters */
 	if (pj_ell_set(pj_get_default_ctx(),start, &geod_a, &es)) emess(1,"ellipse setup failure");
 	/* set units */
-	if ((name = pj_param(NULL,start, "sunits").s) != NULL) {
+	if ((name = pj_param(nullptr,start, "sunits").s) != nullptr) {
 		const char *s;
                 const struct PJ_UNITS *unit_list = proj_list_units();
 		for (i = 0; (s = unit_list[i].id) && strcmp(name, s) ; ++i) ;
@@ -44,27 +44,27 @@ geod_set(int argc, char **argv) {
 	geod_f = es/(1 + sqrt(1 - es));
 	geod_ini();
 	/* check if line or arc mode */
-	if (pj_param(NULL,start, "tlat_1").i) {
+	if (pj_param(nullptr,start, "tlat_1").i) {
 		double del_S;
 #undef f
-		phi1 = pj_param(NULL,start, "rlat_1").f;
-		lam1 = pj_param(NULL,start, "rlon_1").f;
-		if (pj_param(NULL,start, "tlat_2").i) {
-			phi2 = pj_param(NULL,start, "rlat_2").f;
-			lam2 = pj_param(NULL,start, "rlon_2").f;
+		phi1 = pj_param(nullptr,start, "rlat_1").f;
+		lam1 = pj_param(nullptr,start, "rlon_1").f;
+		if (pj_param(nullptr,start, "tlat_2").i) {
+			phi2 = pj_param(nullptr,start, "rlat_2").f;
+			lam2 = pj_param(nullptr,start, "rlon_2").f;
 			geod_inv();
 			geod_pre();
-		} else if ((geod_S = pj_param(NULL,start, "dS").f) != 0.) {
-			al12 = pj_param(NULL,start, "rA").f;
+		} else if ((geod_S = pj_param(nullptr,start, "dS").f) != 0.) {
+			al12 = pj_param(nullptr,start, "rA").f;
 			geod_pre();
 			geod_for();
 		} else emess(1,"incomplete geodesic/arc info");
-		if ((n_alpha = pj_param(NULL,start, "in_A").i) > 0) {
-			if ((del_alpha = pj_param(NULL,start, "rdel_A").f) == 0.0)
+		if ((n_alpha = pj_param(nullptr,start, "in_A").i) > 0) {
+			if ((del_alpha = pj_param(nullptr,start, "rdel_A").f) == 0.0)
 				emess(1,"del azimuth == 0");
-		} else if ((del_S = fabs(pj_param(NULL,start, "ddel_S").f)) != 0.) {
+		} else if ((del_S = fabs(pj_param(nullptr,start, "ddel_S").f)) != 0.) {
 			n_S = (int)(geod_S / del_S + .5);
-		} else if ((n_S = pj_param(NULL,start, "in_S").i) <= 0)
+		} else if ((n_S = pj_param(nullptr,start, "in_S").i) <= 0)
 			emess(1,"no interval divisor selected");
 	}
 	/* free up linked list */
diff --git a/src/gie.c b/src/apps/gie.cpp
index 4bb79f1f..3e4770a2 100644
--- a/src/gie.c
+++ b/src/apps/gie.cpp
@@ -194,7 +194,7 @@ typedef struct {
     FILE *fout;
 } gie_ctx;
 
-ffio *F = 0;
+ffio *F = nullptr;
 
 static gie_ctx T;
 int tests=0, succs=0, succ_fails=0, fail_fails=0, succ_rtps=0, fail_rtps=0;
@@ -236,8 +236,8 @@ static const char usage[] = {
 
 int main (int argc, char **argv) {
     int  i;
-    const char *longflags[]  = {"v=verbose", "q=quiet", "h=help", "l=list", "version", 0};
-    const char *longkeys[]   = {"o=output", 0};
+    const char *longflags[]  = {"v=verbose", "q=quiet", "h=help", "l=list", "version", nullptr};
+    const char *longkeys[]   = {"o=output", nullptr};
     OPTARGS *o;
 
     memset (&T, 0, sizeof (T));
@@ -248,7 +248,7 @@ int main (int argc, char **argv) {
     T.use_proj4_init_rules = FALSE;
 
     o = opt_parse (argc, argv, "hlvq", "o", longflags, longkeys);
-    if (0==o)
+    if (nullptr==o)
         return 0;
 
     if (opt_given (o, "h") || argc==1) {
@@ -274,7 +274,7 @@ int main (int argc, char **argv) {
     if (opt_given (o, "o"))
         T.fout = fopen (opt_arg (o, "output"), "rt");
 
-    if (0==T.fout) {
+    if (nullptr==T.fout) {
         fprintf (stderr, "%s: Cannot open '%s' for output\n", o->progname, opt_arg (o, "output"));
         free (o);
         return 1;
@@ -294,7 +294,7 @@ int main (int argc, char **argv) {
     }
 
     F = ffio_create (gie_tags, n_gie_tags, 1000);
-    if (0==F) {
+    if (nullptr==F) {
         fprintf (stderr, "%s: No memory\n", o->progname);
         free (o);
         return 1;
@@ -379,12 +379,12 @@ static int process_file (const char *fname) {
 
     if (T.skip) {
         proj_destroy (T.P);
-        T.P = 0;
+        T.P = nullptr;
         return 0;
     }
 
     f = fopen (fname, "rt");
-    if (0==f) {
+    if (nullptr==f) {
         if (T.verbosity > 0) {
             fprintf (T.fout, "%sCannot open spec'd input file '%s' - bye!\n", delim, fname);
             return 2;
@@ -400,7 +400,7 @@ static int process_file (const char *fname) {
     while (get_inp(F)) {
         if (SKIP==dispatch (F->tag, F->args)) {
             proj_destroy (T.P);
-            T.P = 0;
+            T.P = nullptr;
             return 0;
         }
     }
@@ -591,10 +591,10 @@ either a conversion or a transformation)
 
     if (T.P)
         proj_destroy (T.P);
-    proj_errno_reset (0);
-    proj_context_use_proj4_init_rules(0, T.use_proj4_init_rules);
+    proj_errno_reset (nullptr);
+    proj_context_use_proj4_init_rules(nullptr, T.use_proj4_init_rules);
 
-    T.P = proj_create (0, F->args);
+    T.P = proj_create (nullptr, F->args);
 
     /* Checking that proj_create succeeds is first done at "expect" time, */
     /* since we want to support "expect"ing specific error codes */
@@ -604,7 +604,7 @@ either a conversion or a transformation)
 
 static PJ_COORD torad_coord (PJ *P, PJ_DIRECTION dir, PJ_COORD a) {
     size_t i, n;
-    char *axis = "enut";
+    const char *axis = "enut";
     paralist *l = pj_param_exists (P->params, "axis");
     if (l && dir==PJ_INV)
         axis = l->param + strlen ("axis=");
@@ -618,7 +618,7 @@ static PJ_COORD torad_coord (PJ *P, PJ_DIRECTION dir, PJ_COORD a) {
 
 static PJ_COORD todeg_coord (PJ *P, PJ_DIRECTION dir, PJ_COORD a) {
     size_t i, n;
-    char *axis = "enut";
+    const char *axis = "enut";
     paralist *l = pj_param_exists (P->params, "axis");
     if (l && dir==PJ_FWD)
         axis = l->param + strlen ("axis=");
@@ -715,7 +715,7 @@ Always returns 0.
     char *endp;
     PJ_COORD coo;
 
-    if (0==T.P) {
+    if (nullptr==T.P) {
         if (T.ignore == proj_errno(T.P))
             return another_skip();
 
@@ -840,7 +840,7 @@ Tell GIE what to expect, when transforming the ACCEPTed input
     if (T.ignore==proj_errno(T.P))
         return another_skip ();
 
-    if (0==T.P) {
+    if (nullptr==T.P) {
         /* If we expect failure, and fail, then it's a success... */
         if (expect_failure) {
             /* Failed to fail correctly? */
@@ -1020,6 +1020,7 @@ static int dispatch (const char *cmnd, const char *args) {
 
 
 
+namespace { // anonymous namespace
 struct errno_vs_err_const {const char *the_err_const; int the_errno;};
 static const struct errno_vs_err_const lookup[] = {
     {"pjd_err_no_args"                  ,  -1},
@@ -1084,6 +1085,7 @@ static const struct errno_vs_err_const lookup[] = {
     {"pjd_err_unknown"                  ,  9999},
     {"pjd_err_enomem"                   ,  ENOMEM},
 };
+} // anonymous namespace
 
 static const struct errno_vs_err_const unknown = {"PJD_ERR_UNKNOWN", 9999};
 
@@ -1195,24 +1197,24 @@ static ffio *ffio_create (const char **tags, size_t n_tags, size_t max_record_si
 /****************************************************************************************
 Constructor for the ffio object.
 ****************************************************************************************/
-    ffio *G = calloc (1, sizeof (ffio));
-    if (0==G)
-        return 0;
+    ffio *G = static_cast<ffio*>(calloc (1, sizeof (ffio)));
+    if (nullptr==G)
+        return nullptr;
 
     if (0==max_record_size)
         max_record_size = 1000;
 
-    G->args = calloc (1, 5*max_record_size);
-    if (0==G->args) {
+    G->args = static_cast<char*>(calloc (1, 5*max_record_size));
+    if (nullptr==G->args) {
         free (G);
-        return 0;
+        return nullptr;
     }
 
-    G->next_args = calloc (1, max_record_size);
-    if (0==G->args) {
+    G->next_args = static_cast<char*>(calloc (1, max_record_size));
+    if (nullptr==G->args) {
         free (G->args);
         free (G);
-        return 0;
+        return nullptr;
     }
 
     G->args_size = 5*max_record_size;
@@ -1236,7 +1238,7 @@ fclose has been called prior to ffio_destroy.
     free (G->args);
     free (G->next_args);
     free (G);
-    return 0;
+    return nullptr;
 }
 
 
@@ -1253,10 +1255,10 @@ continues until a gie command verb is found at the start of a line
 ****************************************************************************************/
     int i;
     char *c;
-    if (0==G)
+    if (nullptr==G)
         return 0;
     c = G->next_args;
-    if (0==c)
+    if (nullptr==c)
         return 0;
     if (0==c[0])
         return 0;
@@ -1277,7 +1279,7 @@ A start of a new command serves as an end delimiter for the current command
     for (j = 0;  j < G->n_tags;  j++)
         if (strncmp (G->next_args, G->tags[j], strlen(G->tags[j]))==0)
             return G->tags[j];
-    return 0;
+    return nullptr;
 }
 
 
@@ -1291,7 +1293,7 @@ instruction, or a "decorative element", i.e. one of the "ascii art" style
 block delimiters typically used to mark up block comments in a free format
 file.
 ****************************************************************************************/
-    if (G==0)
+    if (G==nullptr)
         return 0;
     if (at_decorative_element (G))
         return 1;
@@ -1310,7 +1312,7 @@ Read next line of input file. Returns 1 on success, 0 on failure.
     G->next_args[0] = 0;
     if (T.skip)
         return 0;
-    if (0==fgets (G->next_args, (int) G->next_args_size - 1, G->f))
+    if (nullptr==fgets (G->next_args, (int) G->next_args_size - 1, G->f))
         return 0;
     if (feof (G->f))
         return 0;
@@ -1354,7 +1356,7 @@ Make sure we're inside a <gie>-block. Return 1 on success, 0 otherwise.
         G->next_args[0] = 0;
         if (feof (G->f))
             return 0;
-        if (0==fgets (G->next_args, (int) G->next_args_size - 1, G->f))
+        if (nullptr==fgets (G->next_args, (int) G->next_args_size - 1, G->f))
             return 0;
         pj_chomp (G->next_args);
         G->next_lineno++;
@@ -1412,8 +1414,8 @@ static int append_args (ffio *G) {
 
     /* +2: 1 for the space separator and 1 for the NUL termination. */
     if (G->args_size < args_len + next_len - skip_chars + 2) {
-        void *p = realloc (G->args, 2 * G->args_size);
-        if (0==p)
+        char *p = static_cast<char*>(realloc (G->args, 2 * G->args_size));
+        if (nullptr==p)
             return 0;
         G->args = p;
         G->args_size = 2 * G->args_size;
@@ -1442,7 +1444,7 @@ whitespace etc. The block is stored in G->args. Returns 1 on success, 0 otherwis
         return 0;
     G->tag = at_tag (G);
 
-    if (0==G->tag)
+    if (nullptr==G->tag)
         return 0;
 
     do {
diff --git a/src/nad2bin.c b/src/apps/nad2bin.cpp
index eb8672a5..ff8f2ebd 100644
--- a/src/nad2bin.c
+++ b/src/apps/nad2bin.cpp
@@ -61,7 +61,7 @@ int main(int argc, char **argv) {
     long lam, laml, phi, phil;
     FILE *fp;
 
-    const char *output_file = NULL;
+    const char *output_file = nullptr;
 
     const char *format   = "ctable2";
     const char *GS_TYPE  = "SECONDS";
@@ -81,7 +81,7 @@ int main(int argc, char **argv) {
         {
             format = argv[++i];
         }
-        else if( output_file == NULL )
+        else if( output_file == nullptr )
         {
             output_file = argv[i];
         }
@@ -89,7 +89,7 @@ int main(int argc, char **argv) {
             Usage();
     }
 
-    if( output_file == NULL )
+    if( output_file == nullptr )
         Usage();
 
     fprintf( stdout, "Output Binary File Format: %s\n", format );
@@ -99,7 +99,7 @@ int main(int argc, char **argv) {
 /* ==================================================================== */
 
     memset(ct.id,0,MAX_TAB_ID);
-    if ( NULL == fgets(ct.id, MAX_TAB_ID, stdin) ) {
+    if ( nullptr == fgets(ct.id, MAX_TAB_ID, stdin) ) {
         perror("fgets");
         exit(1);
     }
diff --git a/src/optargpm.h b/src/apps/optargpm.h
index 48cb260b..035c6f92 100644
--- a/src/optargpm.h
+++ b/src/apps/optargpm.h
@@ -107,8 +107,8 @@ int main(int argc, char **argv) {
     char *longkeys[]   = {"o=output", "hello", 0};
 
     o = opt_parse (argc, argv, "hv", "o", longflags, longkeys);
-    if (0==o)
-        return 0;
+    if (nullptr==o)
+        return nullptr;
 
 
     if (opt_given (o, "h")) {
@@ -135,14 +135,14 @@ int main(int argc, char **argv) {
         char buf[1000];
         int ret = fgets (buf, 1000, o->input);
         opt_eof_handler (o);
-        if (0==ret) {
+        if (nullptr==ret) {
             fprintf (stderr, "Read error in record %d\n", (int) o->record_index);
             continue;
         }
         do_what_needs_to_be_done (buf);
     }
 
-    return 0;
+    return nullptr;
 }
 
 
@@ -201,9 +201,9 @@ int opt_record (OPTARGS *opt);
 int opt_input_loop (OPTARGS *opt, int binary);
 static int opt_is_flag (OPTARGS *opt, int ordinal);
 static int opt_raise_flag (OPTARGS *opt, int ordinal);
-static int opt_ordinal (OPTARGS *opt, char *option);
-int opt_given (OPTARGS *opt, char *option);
-char *opt_arg (OPTARGS *opt, char *option);
+static int opt_ordinal (OPTARGS *opt, const char *option);
+int opt_given (OPTARGS *opt, const char *option);
+char *opt_arg (OPTARGS *opt, const char *option);
 const char *opt_strip_path (const char *full_name);
 OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys, const char **longflags, const char **longkeys);
 
@@ -229,22 +229,22 @@ struct OPTARGS {
 
 /* name of file currently read from */
 char *opt_filename (OPTARGS *opt) {
-    if (0==opt)
-        return 0;
+    if (nullptr==opt)
+        return nullptr;
     if (0==opt->fargc)
         return opt->flaglevel;
     return opt->fargv[opt->input_index];
 }
 
 static int opt_eof (OPTARGS *opt) {
-    if (0==opt)
+    if (nullptr==opt)
         return 1;
     return feof (opt->input);
 }
 
 /* record number of most recently read record */
 int opt_record (OPTARGS *opt) {
-    if (0==opt)
+    if (nullptr==opt)
         return 0;
     return opt->record_index + 1;
 }
@@ -252,11 +252,11 @@ int opt_record (OPTARGS *opt) {
 
 /* handle closing/opening of a "stream-of-streams" */
 int opt_input_loop (OPTARGS *opt, int binary) {
-    if (0==opt)
+    if (nullptr==opt)
         return 0;
 
     /* most common case: increment record index and read on */
-    if ( (opt->input!=0) && !feof (opt->input) ) {
+    if ( (opt->input!=nullptr) && !feof (opt->input) ) {
         opt->record_index++;
         return 1;
     }
@@ -264,7 +264,7 @@ int opt_input_loop (OPTARGS *opt, int binary) {
     opt->record_index = 0;
 
     /* no input files specified - read from stdin */
-    if ((0==opt->fargc) && (0==opt->input)) {
+    if ((0==opt->fargc) && (nullptr==opt->input)) {
         opt->input = stdin;
         return 1;
     }
@@ -275,18 +275,18 @@ int opt_input_loop (OPTARGS *opt, int binary) {
         return 0;
 
     /* end if no more input */
-    if (0!=opt->input)
+    if (nullptr!=opt->input)
         fclose (opt->input);
     if (opt->input_index >= opt->fargc)
         return 0;
 
     /* otherwise, open next input file */
     opt->input = fopen (opt->fargv[opt->input_index++], binary? "rb": "rt");
-    if (0 != opt->input)
+    if (nullptr != opt->input)
         return 1;
 
     /* ignore non-existing files - go on! */
-    if (0==opt->input)
+    if (nullptr==opt->input)
         return opt_input_loop (opt, binary);
     return 0;
 }
@@ -315,18 +315,18 @@ static int opt_raise_flag (OPTARGS *opt, int ordinal) {
 }
 
 /* Find the ordinal value of any (short or long) option */
-static int opt_ordinal (OPTARGS *opt, char *option) {
+static int opt_ordinal (OPTARGS *opt, const char *option) {
     int i;
-    if (0==opt)
+    if (nullptr==opt)
         return 0;
-    if (0==option)
+    if (nullptr==option)
         return 0;
     if (0==option[0])
         return 0;
     /* An ordinary -o style short option */
     if (strlen (option)==1) {
         /* Undefined option? */
-        if (0==opt->optarg[(int) option[0]])
+        if (nullptr==opt->optarg[(int) option[0]])
             return 0;
         return (int) option[0];
     }
@@ -334,9 +334,9 @@ static int opt_ordinal (OPTARGS *opt, char *option) {
     /* --longname style long options are slightly harder */
     for (i = 0; i < 64; i++) {
         const char **f = opt->longflags;
-        if (0==f)
+        if (nullptr==f)
             break;
-        if (0==f[i])
+        if (nullptr==f[i])
             break;
         if (0==strcmp(f[i], "END"))
             break;
@@ -346,7 +346,7 @@ static int opt_ordinal (OPTARGS *opt, char *option) {
         /* long alias? - return ordinal for corresponding short */
         if ((strlen(f[i]) > 2) && (f[i][1]=='=') && (0==strcmp(f[i]+2, option))) {
                 /* Undefined option? */
-                if (0==opt->optarg[(int) f[i][0]])
+                if (nullptr==opt->optarg[(int) f[i][0]])
                     return 0;
                 return (int) f[i][0];
         }
@@ -354,9 +354,9 @@ static int opt_ordinal (OPTARGS *opt, char *option) {
 
     for (i = 0; i < 64; i++) {
         const char **v = opt->longkeys;
-        if (0==v)
+        if (nullptr==v)
             return 0;
-        if (0==v[i])
+        if (nullptr==v[i])
             return 0;
         if (0==strcmp (v[i], "END"))
             return 0;
@@ -366,20 +366,20 @@ static int opt_ordinal (OPTARGS *opt, char *option) {
         /* long alias? - return ordinal for corresponding short */
         if ((strlen(v[i]) > 2) && (v[i][1]=='=') && (0==strcmp(v[i]+2, option))) {
             /* Undefined option? */
-            if (0==opt->optarg[(int) v[i][0]])
+            if (nullptr==opt->optarg[(int) v[i][0]])
                 return 0;
             return (int) v[i][0];
         }
 
     }
     /* kill some potential compiler warnings about unused functions */
-    (void) opt_eof (0);
+    (void) opt_eof (nullptr);
     return 0;
 }
 
 
 /* Returns 0 if option was not given on command line, non-0 otherwise */
-int opt_given (OPTARGS *opt, char *option) {
+int opt_given (OPTARGS *opt, const char *option) {
     int ordinal = opt_ordinal (opt, option);
     if (0==ordinal)
         return 0;
@@ -391,10 +391,10 @@ int opt_given (OPTARGS *opt, char *option) {
 
 
 /* Returns the argument to a given option */
-char *opt_arg (OPTARGS *opt, char *option) {
+char *opt_arg (OPTARGS *opt, const char *option) {
     int ordinal = opt_ordinal (opt, option);
     if (0==ordinal)
-        return 0;
+        return nullptr;
     return opt->optarg[ordinal];
 }
 
@@ -418,8 +418,8 @@ OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys,
     OPTARGS *o;
 
     o = (OPTARGS *) calloc (1, sizeof(OPTARGS));
-    if (0==o)
-        return 0;
+    if (nullptr==o)
+        return nullptr;
 
     o->argc = argc;
     o->argv = argv;
@@ -448,10 +448,10 @@ OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys,
             continue;
         if ('='!=longflags[i][1])
             continue;
-        if (0==strchr (flags, longflags[i][0])) {
+        if (nullptr==strchr (flags, longflags[i][0])) {
             fprintf (stderr, "%s: Invalid alias - '%s'. Valid short flags are '%s'\n", o->progname, longflags[i], flags);
             free (o);
-            return 0;
+            return nullptr;
         }
     }
     for (i = 0;  longkeys && longkeys[i]; i++) {
@@ -460,10 +460,10 @@ OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys,
             continue;
         if ('='!=longkeys[i][1])
             continue;
-        if (0==strchr (keys, longkeys[i][0])) {
+        if (nullptr==strchr (keys, longkeys[i][0])) {
             fprintf (stderr, "%s: Invalid alias - '%s'. Valid short flags are '%s'\n", o->progname, longkeys[i], keys);
             free (o);
-            return 0;
+            return nullptr;
         }
     }
 
@@ -471,20 +471,20 @@ OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys,
     /* flaglevel array to provide a pseudo-filename for the case of reading from stdin      */
     strcpy (o->flaglevel, "<stdin>");
 
-    for (i = 128; (longflags != 0) && (longflags[i - 128] != 0); i++) {
+    for (i = 128; (longflags != nullptr) && (longflags[i - 128] != nullptr); i++) {
         if (i==192) {
             free (o);
             fprintf (stderr, "Too many flag style long options\n");
-            return 0;
+            return nullptr;
         }
         o->optarg[i] = o->flaglevel;
     }
 
-    for (i = 192;  (longkeys != 0) && (longkeys[i - 192] != 0);  i++) {
+    for (i = 192;  (longkeys != nullptr) && (longkeys[i - 192] != nullptr);  i++) {
         if (i==256) {
             free (o);
             fprintf (stderr, "Too many value style long options\n");
-            return 0;
+            return nullptr;
         }
         o->optarg[i] = argv[0];
     }
@@ -500,7 +500,7 @@ OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys,
         if ('-' != argv[i][0])
             break;
 
-        if (0==o->margv)
+        if (nullptr==o->margv)
             o->margv = argv + i;
         o->margc++;
 
@@ -526,7 +526,7 @@ OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys,
                 c = opt_ordinal (o, crepr);
                 if (0==c) {
                     fprintf (stderr, "Invalid option \"%s\"\n", crepr);
-                    return (OPTARGS *) 0;
+                    return nullptr;
                 }
 
                 /* inline (gnu) --foo=bar style arg */
@@ -534,7 +534,7 @@ OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys,
                     *equals = '=';
                     if (opt_is_flag (o, c)) {
                         fprintf (stderr, "Option \"%s\" takes no arguments\n", crepr);
-                        return (OPTARGS *) 0;
+                        return nullptr;
                     }
                     o->optarg[c] = equals + 1;
                     break;
@@ -544,7 +544,7 @@ OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys,
                 if (!opt_is_flag (o, c)) {
                     if ((argc==i + 1) || ('+'==argv[i+1][0]) || ('-'==argv[i+1][0])) {
                         fprintf (stderr, "Missing argument for option \"%s\"\n", crepr);
-                        return (OPTARGS *) 0;
+                        return nullptr;
                     }
                     o->optarg[c] = argv[i + 1];
                     i++; /* eat the arg */
@@ -553,7 +553,7 @@ OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys,
 
                 if (!opt_is_flag (o, c)) {
                     fprintf (stderr, "Expected flag style long option here, but got \"%s\"\n", crepr);
-                    return (OPTARGS *) 0;
+                    return nullptr;
                 }
 
                 /* Flag style option, i.e. taking no arguments */
@@ -562,9 +562,9 @@ OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys,
             }
 
             /* classic short options */
-            if (0==o->optarg[c]) {
+            if (nullptr==o->optarg[c]) {
                 fprintf (stderr, "Invalid option \"%s\"\n", crepr);
-                return (OPTARGS *) 0;
+                return nullptr;
             }
 
             /* Flag style option, i.e. taking no arguments */
@@ -580,7 +580,7 @@ OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys,
                 if ((argc==i + 1) || ('+'==argv[i+1][0]) || ('-'==argv[i+1][0]))
                 {
                     fprintf (stderr, "Bad or missing arg for option \"%s\"\n", crepr);
-                    return (OPTARGS *) 0;
+                    return nullptr;
                 }
                 o->optarg[(int) c] = argv[i + 1];
                 i++;
@@ -617,7 +617,7 @@ OPTARGS *opt_parse (int argc, char **argv, const char *flags, const char *keys,
         if ('-' == argv[i][0]) {
             free (o);
             fprintf (stderr, "+ and - style options must not be mixed\n");
-            return 0;
+            return nullptr;
         }
 
         if ('+' != argv[i][0])
diff --git a/src/p_series.c b/src/apps/p_series.cpp
index cddea888..cddea888 100644
--- a/src/p_series.c
+++ b/src/apps/p_series.cpp
diff --git a/src/proj.c b/src/apps/proj.cpp
index 2405781c..b93fb04d 100644
--- a/src/proj.c
+++ b/src/apps/proj.cpp
@@ -20,7 +20,7 @@
 #define MAX_PARGS 100
 #define PJ_INVERS(P) (P->inv ? 1 : 0)
 
-extern void gen_cheb(int, projUV(*)(projUV), char *, PJ *, int, char **);
+extern void gen_cheb(int, projUV(*)(projUV), const char *, PJ *, int, char **);
 
 static PJ *Proj;
 static union {
@@ -42,10 +42,10 @@ static int
     very_verby = 0, /* very verbose mode */
     postscale = 0;
 
-static char
+static const char
     *cheby_str,         /* string controlling Chebychev evaluation */
-    *oform = (char *)0, /* output format for x-y or decimal degrees */
-    oform_buffer[16];   /* Buffer for oform when using -d */
+    *oform = nullptr; /* output format for x-y or decimal degrees */
+static char oform_buffer[16];   /* Buffer for oform when using -d */
 
 static const char
     *oterr = "*\t*",    /* output line for unprojectable input */
@@ -74,7 +74,7 @@ static projUV int_proj(projUV data) {
 
 /* file processing function */
 static void process(FILE *fid) {
-    char line[MAX_LINE+3], *s = 0, pline[40];
+    char line[MAX_LINE+3], *s = nullptr, pline[40];
     PJ_COORD data;
 
     for (;;) {
@@ -309,11 +309,12 @@ static void vprocess(FILE *fid) {
 }
 
 int main(int argc, char **argv) {
-    char *arg, **eargv = argv, *pargv[MAX_PARGS], **iargv = argv;
+    char *arg, *pargv[MAX_PARGS], **iargv = argv;
+    char **eargv = argv;
     FILE *fid;
     int pargc = 0, iargc = argc, eargc = 0, mon = 0;
 
-    if ( (emess_dat.Prog_name = strrchr(*argv,DIR_CHAR)) != NULL)
+    if ( (emess_dat.Prog_name = strrchr(*argv,DIR_CHAR)) != nullptr)
         ++emess_dat.Prog_name;
     else emess_dat.Prog_name = *argv;
     inverse = ! strncmp(emess_dat.Prog_name, "inv", 3);
@@ -327,7 +328,7 @@ int main(int argc, char **argv) {
         if(**++argv == '-') for(arg = *argv;;) {
             switch(*++arg) {
               case '\0': /* position of "stdin" */
-                if (arg[-1] == '-') eargv[eargc++] = "-";
+                if (arg[-1] == '-') eargv[eargc++] = const_cast<char*>("-");
                 break;
               case 'b': /* binary I/O */
                 bin_in = bin_out = 1;
@@ -410,7 +411,7 @@ int main(int argc, char **argv) {
                     {
                         printf("%12s %-12s %-30s\n",
                                ld->id, ld->ellipse_id, ld->defn);
-                        if( ld->comments != NULL && strlen(ld->comments) > 0 )
+                        if( ld->comments != nullptr && strlen(ld->comments) > 0 )
                             printf( "%25s %s\n", " ", ld->comments );
                     }
                 } else
@@ -482,7 +483,7 @@ int main(int argc, char **argv) {
             eargv[eargc++] = *argv;
     }
     if (eargc == 0 && !cheby_str) /* if no specific files force sysin */
-        eargv[eargc++] = "-";
+        eargv[eargc++] = const_cast<char*>("-");
     else if (eargc > 0 && cheby_str) /* warning */
         emess(4, "data files when generating Chebychev prohibited");
     /* done with parameter and control input */
@@ -551,7 +552,7 @@ int main(int argc, char **argv) {
     for ( ; eargc-- ; ++eargv) {
         if (**eargv == '-') {
             fid = stdin;
-            emess_dat.File_name = "<stdin>";
+            emess_dat.File_name = const_cast<char*>("<stdin>");
 
             if (bin_in)
             {
@@ -559,7 +560,7 @@ int main(int argc, char **argv) {
             }
 
         } else {
-            if ((fid = fopen(*eargv, "rb")) == NULL) {
+            if ((fid = fopen(*eargv, "rb")) == nullptr) {
                 emess(-2, *eargv, "input file");
                 continue;
             }
@@ -571,7 +572,7 @@ int main(int argc, char **argv) {
         else
             process(fid);
         (void)fclose(fid);
-        emess_dat.File_name = 0;
+        emess_dat.File_name = nullptr;
     }
 
     if( Proj )
diff --git a/src/proj_strtod.c b/src/apps/proj_strtod.cpp
index a3bc7d40..b8edc6a3 100644
--- a/src/proj_strtod.c
+++ b/src/apps/proj_strtod.cpp
@@ -106,7 +106,7 @@ double proj_strtod(const char *str, char **endptr) {
     int num_digits_after_comma  = 0;
     int num_prefixed_zeros      = 0;
 
-    if (0==str) {
+    if (nullptr==str) {
         errno = EFAULT;
         if (endptr)
             *endptr = p;
@@ -125,7 +125,7 @@ double proj_strtod(const char *str, char **endptr) {
     }
 
     /* non-numeric? */
-    if (0==strchr("0123456789+-._", *p)) {
+    if (nullptr==strchr("0123456789+-._", *p)) {
         if (endptr)
             *endptr = (char *) str;
         return 0;
@@ -150,7 +150,7 @@ double proj_strtod(const char *str, char **endptr) {
     }
 
     /* stray sign, as in "+/-"? */
-    if (0!=sign && (0==strchr ("0123456789._", *p) || 0==*p)) {
+    if (0!=sign && (nullptr==strchr ("0123456789._", *p) || 0==*p)) {
         if (endptr)
             *endptr = (char *) str;
         return 0;
@@ -161,7 +161,7 @@ double proj_strtod(const char *str, char **endptr) {
         p++;
 
     /* zero? */
-    if ((0==*p) || 0==strchr ("0123456789eE.", *p) || isspace(*p)) {
+    if ((0==*p) || nullptr==strchr ("0123456789eE.", *p) || isspace(*p)) {
         if (endptr)
             *endptr = p;
         return sign==-1? -0: 0;
@@ -202,7 +202,7 @@ double proj_strtod(const char *str, char **endptr) {
             }
 
         /* if the next character is nonnumeric, we have reached the end */
-        if (0==*p || 0==strchr ("_0123456789eE+-", *p)) {
+        if (0==*p || nullptr==strchr ("_0123456789eE+-", *p)) {
             if (endptr)
                 *endptr = p;
             if (sign==-1)
@@ -249,7 +249,7 @@ double proj_strtod(const char *str, char **endptr) {
         p++;
 
         /* Just a stray "e", as in 100elephants? */
-        if (0==*p || 0==strchr ("0123456789+-_", *p)) {
+        if (0==*p || nullptr==strchr ("0123456789+-_", *p)) {
             p--;
             break;
         }
@@ -315,7 +315,7 @@ double proj_strtod(const char *str, char **endptr) {
 }
 
 double proj_atof(const char *str) {
-    return proj_strtod(str, (void *) 0);
+    return proj_strtod(str, nullptr);
 }
 
 #ifdef TEST
diff --git a/src/proj_strtod.h b/src/apps/proj_strtod.h
index 38c2d1f4..38c2d1f4 100644
--- a/src/proj_strtod.h
+++ b/src/apps/proj_strtod.h
diff --git a/src/projinfo.cpp b/src/apps/projinfo.cpp
index 89b42e12..d604365a 100644
--- a/src/projinfo.cpp
+++ b/src/apps/projinfo.cpp
@@ -56,6 +56,7 @@ using namespace NS_PROJ::internal;
 
 // ---------------------------------------------------------------------------
 
+namespace { // anonymous namespace
 struct OutputOptions {
     bool quiet = false;
     bool PROJ5 = false;
@@ -69,6 +70,7 @@ struct OutputOptions {
     bool c_ify = false;
     bool singleLine = false;
 };
+} // anonymous namespace
 
 // ---------------------------------------------------------------------------
 
diff --git a/src/pj_auth.c b/src/auth.cpp
index d6024671..cde60a29 100644
--- a/src/pj_auth.c
+++ b/src/auth.cpp
@@ -17,7 +17,7 @@
 pj_authset(double es) {
 	double t, *APA;
 
-	if ((APA = (double *)pj_malloc(APA_SIZE * sizeof(double))) != NULL) {
+	if ((APA = (double *)pj_malloc(APA_SIZE * sizeof(double))) != nullptr) {
 		APA[0] = es * P00;
 		t = es * es;
 		APA[0] += t * P01;
diff --git a/src/bch2bps.c b/src/bch2bps.cpp
index 3ee56993..3ee56993 100644
--- a/src/bch2bps.c
+++ b/src/bch2bps.cpp
diff --git a/src/bchgen.c b/src/bchgen.cpp
index c129f0c1..c129f0c1 100644
--- a/src/bchgen.c
+++ b/src/bchgen.cpp
diff --git a/src/bin_cct.cmake b/src/bin_cct.cmake
index 37752217..e400caf3 100644
--- a/src/bin_cct.cmake
+++ b/src/bin_cct.cmake
@@ -1,5 +1,5 @@
-set(CCT_SRC cct.c proj_strtod.c proj_strtod.h)
-set(CCT_INCLUDE optargpm.h)
+set(CCT_SRC apps/cct.cpp apps/proj_strtod.cpp apps/proj_strtod.h)
+set(CCT_INCLUDE apps/optargpm.h)
 
 source_group("Source Files\\Bin" FILES ${CCT_SRC})
 
diff --git a/src/bin_cs2cs.cmake b/src/bin_cs2cs.cmake
index 9c013dcc..c9543e89 100644
--- a/src/bin_cs2cs.cmake
+++ b/src/bin_cs2cs.cmake
@@ -1,6 +1,8 @@
-set(CS2CS_SRC cs2cs.cpp
-              gen_cheb.c 
-              p_series.c)
+set(CS2CS_SRC apps/cs2cs.cpp
+              apps/gen_cheb.cpp 
+              apps/p_series.cpp
+              apps/emess.cpp
+)
 
 source_group("Source Files\\Bin" FILES ${CS2CS_SRC})
 
diff --git a/src/bin_geod.cmake b/src/bin_geod.cmake
index 1f9ee788..049da318 100644
--- a/src/bin_geod.cmake
+++ b/src/bin_geod.cmake
@@ -1,6 +1,9 @@
-set(GEOD_SRC geod.c
-             geod_set.c geod_interface.c )
-set(GEOD_INCLUDE geod_interface.h)
+set(GEOD_SRC apps/geod.cpp
+             apps/geod_set.cpp
+             apps/geod_interface.cpp
+             apps/emess.cpp
+)
+set(GEOD_INCLUDE apps/geod_interface.h)
 
 source_group("Source Files\\Bin" FILES ${GEOD_SRC} ${GEOD_INCLUDE})
 
diff --git a/src/bin_geodtest.cmake b/src/bin_geodtest.cmake
index 743c630e..31de499d 100644
--- a/src/bin_geodtest.cmake
+++ b/src/bin_geodtest.cmake
@@ -1,4 +1,4 @@
-set(GEODTEST_SRC geodtest.c )
+set(GEODTEST_SRC tests/geodtest.cpp )
 set(GEODTEST_INCLUDE)
 
 source_group("Source Files\\Bin" FILES ${GEODTEST_SRC} ${GEODTEST_INCLUDE})
diff --git a/src/bin_gie.cmake b/src/bin_gie.cmake
index 596592fa..497315f9 100644
--- a/src/bin_gie.cmake
+++ b/src/bin_gie.cmake
@@ -1,5 +1,7 @@
-set(GIE_SRC gie.c proj_strtod.c proj_strtod.h)
-set(GIE_INCLUDE optargpm.h)
+set(GIE_SRC apps/gie.cpp
+            apps/proj_strtod.cpp
+            apps/proj_strtod.h)
+set(GIE_INCLUDE apps/optargpm.h)
 
 source_group("Source Files\\Bin" FILES ${GIE_SRC})
 
diff --git a/src/bin_nad2bin.cmake b/src/bin_nad2bin.cmake
index 0d0fd473..271aac93 100644
--- a/src/bin_nad2bin.cmake
+++ b/src/bin_nad2bin.cmake
@@ -3,7 +3,7 @@ if(WIN32 AND BUILD_LIBPROJ_SHARED)
 endif(WIN32 AND BUILD_LIBPROJ_SHARED)
 
 
-set(NAD2BIN_SRC nad2bin.c)
+set(NAD2BIN_SRC apps/nad2bin.cpp)
 source_group("Source Files\\Bin" FILES ${NAD2BIN_SRC})
 
 #Executable
diff --git a/src/bin_proj.cmake b/src/bin_proj.cmake
index fb7c885d..4bd690ff 100644
--- a/src/bin_proj.cmake
+++ b/src/bin_proj.cmake
@@ -1,6 +1,8 @@
-set(PROJ_SRC proj.c 
-             gen_cheb.c 
-             p_series.c)
+set(PROJ_SRC apps/proj.cpp 
+             apps/gen_cheb.cpp 
+             apps/p_series.cpp
+             apps/emess.cpp
+)
 
 source_group("Source Files\\Bin" FILES ${PROJ_SRC})
 
diff --git a/src/bin_projinfo.cmake b/src/bin_projinfo.cmake
index a422a16d..ea6f1006 100644
--- a/src/bin_projinfo.cmake
+++ b/src/bin_projinfo.cmake
@@ -1,4 +1,4 @@
-set(PROJINFO_SRC projinfo.cpp)
+set(PROJINFO_SRC apps/projinfo.cpp)
 
 source_group("Source Files\\Bin" FILES ${PROJINFO_SRC})
 
diff --git a/src/biveval.c b/src/biveval.cpp
index 05e83e21..05e83e21 100644
--- a/src/biveval.c
+++ b/src/biveval.cpp
diff --git a/src/PJ_axisswap.c b/src/conversions/axisswap.cpp
index 6db4a7d2..8714ec85 100644
--- a/src/PJ_axisswap.c
+++ b/src/conversions/axisswap.cpp
@@ -62,10 +62,12 @@ operation:
 
 PROJ_HEAD(axisswap, "Axis ordering");
 
+namespace { // anonymous namespace
 struct pj_opaque {
     unsigned int axis[4];
     int sign[4];
 };
+} // anonymous namespace
 
 static int sign(int x) {
     return (x > 0) - (x < 0);
@@ -161,11 +163,11 @@ static PJ_COORD reverse_4d(PJ_COORD coo, PJ *P) {
 /***********************************************************************/
 PJ *CONVERSION(axisswap,0) {
 /***********************************************************************/
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
     char *s;
     unsigned int i, j, n = 0;
 
-    if (0==Q)
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = (void *) Q;
 
@@ -187,7 +189,7 @@ PJ *CONVERSION(axisswap,0) {
 
         /* check that all characters are valid */
         for (i=0; i<strlen(order); i++)
-            if (strchr("1234-,", order[i]) == 0) {
+            if (strchr("1234-,", order[i]) == nullptr) {
                 proj_log_error(P, "axisswap: unknown axis '%c'", order[i]);
                 return pj_default_destructor(P, PJD_ERR_AXIS);
             }
@@ -273,7 +275,7 @@ PJ *CONVERSION(axisswap,0) {
     }
 
 
-    if (P->fwd4d == NULL && P->fwd3d == NULL && P->fwd == NULL) {
+    if (P->fwd4d == nullptr && P->fwd3d == nullptr && P->fwd == nullptr) {
         proj_log_error(P, "swapaxis: bad axis order");
         return pj_default_destructor(P, PJD_ERR_AXIS);
     }
diff --git a/src/PJ_cart.c b/src/conversions/cart.cpp
index 6fed9985..6fed9985 100644
--- a/src/PJ_cart.c
+++ b/src/conversions/cart.cpp
diff --git a/src/PJ_geoc.c b/src/conversions/geoc.cpp
index 0455fada..0455fada 100644
--- a/src/PJ_geoc.c
+++ b/src/conversions/geoc.cpp
diff --git a/src/pj_geocent.c b/src/conversions/geocent.cpp
index 0e9d725e..0e9d725e 100644
--- a/src/pj_geocent.c
+++ b/src/conversions/geocent.cpp
diff --git a/src/PJ_unitconvert.c b/src/conversions/unitconvert.cpp
index 402941a4..b25fd5d2 100644
--- a/src/PJ_unitconvert.c
+++ b/src/conversions/unitconvert.cpp
@@ -78,19 +78,23 @@ PROJ_HEAD(unitconvert, "Unit conversion");
 
 typedef double (*tconvert)(double);
 
+namespace { // anonymous namespace
 struct TIME_UNITS {
-    char        *id;        /* units keyword */
+    const char  *id;        /* units keyword */
     tconvert     t_in;      /* unit -> mod. julian date function pointer */
     tconvert     t_out;     /* mod. julian date > unit function pointer */
-    char        *name;      /* comments */
+    const char  *name;      /* comments */
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque_unitconvert {
     int     t_in_id;        /* time unit id for the time input unit   */
     int     t_out_id;       /* time unit id for the time output unit  */
     double  xy_factor;      /* unit conversion factor for horizontal components */
     double  z_factor;       /* unit conversion factor for vertical components */
 };
+} // anonymous namespace
 
 
 /***********************************************************************/
@@ -272,7 +276,7 @@ static const struct TIME_UNITS time_units[] = {
     {"decimalyear", decimalyear_to_mjd, mjd_to_decimalyear, "Decimal year"},
     {"gps_week",    gps_week_to_mjd,    mjd_to_gps_week,    "GPS Week"},
     {"yyyymmdd",    yyyymmdd_to_mjd,    mjd_to_yyyymmdd,    "YYYYMMDD date"},
-    {NULL,          NULL,               NULL,               NULL}
+    {nullptr,          nullptr,               nullptr,               nullptr}
 };
 
 
@@ -420,7 +424,7 @@ static double get_unit_conversion_factor(const char* name,
         }
     }
     if( p_normalized_name ) {
-        *p_normalized_name = NULL;
+        *p_normalized_name = nullptr;
     }
     if( p_is_linear ) {
         *p_is_linear = -1;
@@ -431,8 +435,8 @@ static double get_unit_conversion_factor(const char* name,
 /***********************************************************************/
 PJ *CONVERSION(unitconvert,0) {
 /***********************************************************************/
-    struct pj_opaque_unitconvert *Q = pj_calloc (1, sizeof (struct pj_opaque_unitconvert));
-    char *s, *name;
+    struct pj_opaque_unitconvert *Q = static_cast<struct pj_opaque_unitconvert*>(pj_calloc (1, sizeof (struct pj_opaque_unitconvert)));
+    const char *s, *name;
     int i;
     double f;
     int xy_in_is_linear = -1; /* unknown */
@@ -440,7 +444,7 @@ PJ *CONVERSION(unitconvert,0) {
     int z_in_is_linear = -1; /* unknown */
     int z_out_is_linear = -1; /* unknown */
 
-    if (0==Q)
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = (void *) Q;
 
@@ -461,8 +465,8 @@ PJ *CONVERSION(unitconvert,0) {
     Q->xy_factor = 1.0;
     Q->z_factor  = 1.0;
 
-    if ((name = pj_param (P->ctx, P->params, "sxy_in").s) != NULL) {
-        const char* normalized_name = NULL;
+    if ((name = pj_param (P->ctx, P->params, "sxy_in").s) != nullptr) {
+        const char* normalized_name = nullptr;
         f = get_unit_conversion_factor(name, &xy_in_is_linear, &normalized_name);
         if (f != 0.0) {
             proj_log_debug(P, "xy_in unit: %s", normalized_name);
@@ -474,8 +478,8 @@ PJ *CONVERSION(unitconvert,0) {
             Q->xy_factor *= f;
     }
 
-    if ((name = pj_param (P->ctx, P->params, "sxy_out").s) != NULL) {
-        const char* normalized_name = NULL;
+    if ((name = pj_param (P->ctx, P->params, "sxy_out").s) != nullptr) {
+        const char* normalized_name = nullptr;
         f = get_unit_conversion_factor(name, &xy_out_is_linear, &normalized_name);
         if (f != 0.0) {
             proj_log_debug(P, "xy_out unit: %s", normalized_name);
@@ -493,8 +497,8 @@ PJ *CONVERSION(unitconvert,0) {
         return pj_default_destructor(P, PJD_ERR_INCONSISTENT_UNIT);
     }
 
-    if ((name = pj_param (P->ctx, P->params, "sz_in").s) != NULL) {
-        const char* normalized_name = NULL;
+    if ((name = pj_param (P->ctx, P->params, "sz_in").s) != nullptr) {
+        const char* normalized_name = nullptr;
         f = get_unit_conversion_factor(name, &z_in_is_linear, &normalized_name);
         if (f != 0.0) {
             proj_log_debug(P, "z_in unit: %s", normalized_name);
@@ -506,8 +510,8 @@ PJ *CONVERSION(unitconvert,0) {
             Q->z_factor *= f;
     }
 
-    if ((name = pj_param (P->ctx, P->params, "sz_out").s) != NULL) {
-        const char* normalized_name = NULL;
+    if ((name = pj_param (P->ctx, P->params, "sz_out").s) != nullptr) {
+        const char* normalized_name = nullptr;
         f = get_unit_conversion_factor(name, &z_out_is_linear, &normalized_name);
         if (f != 0.0) {
             proj_log_debug(P, "z_out unit: %s", normalized_name);
@@ -525,7 +529,7 @@ PJ *CONVERSION(unitconvert,0) {
         return pj_default_destructor(P, PJD_ERR_INCONSISTENT_UNIT);
     }
 
-    if ((name = pj_param (P->ctx, P->params, "st_in").s) != NULL) {
+    if ((name = pj_param (P->ctx, P->params, "st_in").s) != nullptr) {
         for (i = 0; (s = time_units[i].id) && strcmp(name, s) ; ++i);
 
         if (!s) return pj_default_destructor(P, PJD_ERR_UNKNOWN_UNIT_ID); /* unknown unit conversion id */
@@ -534,8 +538,8 @@ PJ *CONVERSION(unitconvert,0) {
         proj_log_debug(P, "t_in unit: %s", time_units[i].name);
     }
 
-    s = 0;
-    if ((name = pj_param (P->ctx, P->params, "st_out").s) != NULL) {
+    s = nullptr;
+    if ((name = pj_param (P->ctx, P->params, "st_out").s) != nullptr) {
         for (i = 0; (s = time_units[i].id) && strcmp(name, s) ; ++i);
 
         if (!s) return pj_default_destructor(P, PJD_ERR_UNKNOWN_UNIT_ID); /* unknown unit conversion id */
diff --git a/src/pj_ctx.c b/src/ctx.cpp
index 1c99e921..ab51d6c1 100644
--- a/src/pj_ctx.c
+++ b/src/ctx.cpp
@@ -42,9 +42,9 @@ static volatile int       default_context_initialized = 0;
 projCtx pj_get_ctx( projPJ pj )
 
 {
-    if (0==pj)
+    if (nullptr==pj)
         return pj_get_default_ctx ();
-    if (0==pj->ctx)
+    if (nullptr==pj->ctx)
         return pj_get_default_ctx ();
     return pj->ctx;
 }
@@ -58,7 +58,7 @@ projCtx pj_get_ctx( projPJ pj )
 void pj_set_ctx( projPJ pj, projCtx ctx )
 
 {
-    if (pj==0)
+    if (pj==nullptr)
         return;
     pj->ctx = ctx;
 }
@@ -82,13 +82,13 @@ projCtx pj_get_default_ctx()
         default_context.last_errno = 0;
         default_context.debug_level = PJ_LOG_NONE;
         default_context.logger = pj_stderr_logger;
-        default_context.app_data = NULL;
+        default_context.app_data = nullptr;
         default_context.fileapi = pj_get_default_fileapi();
-        default_context.cpp_context = NULL;
+        default_context.cpp_context = nullptr;
         default_context.use_proj4_init_rules = -1;
         default_context.epsg_file_exists = -1;
 
-        if( getenv("PROJ_DEBUG") != NULL )
+        if( getenv("PROJ_DEBUG") != nullptr )
         {
             if( atoi(getenv("PROJ_DEBUG")) >= -PJ_LOG_DEBUG_MINOR )
                 default_context.debug_level = atoi(getenv("PROJ_DEBUG"));
@@ -111,11 +111,11 @@ projCtx pj_ctx_alloc()
 
 {
     projCtx ctx = (projCtx_t *) malloc(sizeof(projCtx_t));
-    if (0==ctx)
-        return 0;
+    if (nullptr==ctx)
+        return nullptr;
     memcpy( ctx, pj_get_default_ctx(), sizeof(projCtx_t) );
     ctx->last_errno = 0;
-    ctx->cpp_context = NULL;
+    ctx->cpp_context = nullptr;
     ctx->use_proj4_init_rules = -1;
 
     return ctx;
@@ -139,7 +139,7 @@ void pj_ctx_free( projCtx ctx )
 int pj_ctx_get_errno( projCtx ctx )
 
 {
-    if (0==ctx)
+    if (nullptr==ctx)
         return pj_get_default_ctx ()->last_errno;
     return ctx->last_errno;
 }
@@ -167,7 +167,7 @@ void pj_ctx_set_errno( projCtx ctx, int new_errno )
 void pj_ctx_set_debug( projCtx ctx, int new_debug )
 
 {
-    if (0==ctx)
+    if (nullptr==ctx)
         return;
     ctx->debug_level = new_debug;
 }
@@ -179,7 +179,7 @@ void pj_ctx_set_debug( projCtx ctx, int new_debug )
 void pj_ctx_set_logger( projCtx ctx, void (*new_logger)(void*,int,const char*) )
 
 {
-    if (0==ctx)
+    if (nullptr==ctx)
         return;
     ctx->logger = new_logger;
 }
@@ -191,7 +191,7 @@ void pj_ctx_set_logger( projCtx ctx, void (*new_logger)(void*,int,const char*) )
 void pj_ctx_set_app_data( projCtx ctx, void *new_app_data )
 
 {
-    if (0==ctx)
+    if (nullptr==ctx)
         return;
     ctx->app_data = new_app_data;
 }
@@ -203,8 +203,8 @@ void pj_ctx_set_app_data( projCtx ctx, void *new_app_data )
 void *pj_ctx_get_app_data( projCtx ctx )
 
 {
-    if (0==ctx)
-        return 0;
+    if (nullptr==ctx)
+        return nullptr;
     return ctx->app_data;
 }
 
@@ -215,7 +215,7 @@ void *pj_ctx_get_app_data( projCtx ctx )
 void pj_ctx_set_fileapi( projCtx ctx, projFileAPI *fileapi )
 
 {
-    if (0==ctx)
+    if (nullptr==ctx)
         return;
     ctx->fileapi = fileapi;
 }
@@ -227,7 +227,7 @@ void pj_ctx_set_fileapi( projCtx ctx, projFileAPI *fileapi )
 projFileAPI *pj_ctx_get_fileapi( projCtx ctx )
 
 {
-    if (0==ctx)
-        return 0;
+    if (nullptr==ctx)
+        return nullptr;
     return ctx->fileapi;
 }
diff --git a/src/pj_datum_set.c b/src/datum_set.cpp
index 466b56c5..c9dfdb80 100644
--- a/src/pj_datum_set.c
+++ b/src/datum_set.cpp
@@ -54,7 +54,7 @@ int pj_datum_set(projCtx ctx, paralist *pl, PJ *projdef)
 /*      definition will last into the pj_ell_set() function called      */
 /*      after this one.                                                 */
 /* -------------------------------------------------------------------- */
-    if( (name = pj_param(ctx, pl,"sdatum").s) != NULL )
+    if( (name = pj_param(ctx, pl,"sdatum").s) != nullptr )
     {
         paralist *curr;
         const char *s;
@@ -96,7 +96,7 @@ int pj_datum_set(projCtx ctx, paralist *pl, PJ *projdef)
 /*      Check for nadgrids parameter.                                   */
 /* -------------------------------------------------------------------- */
     nadgrids = pj_param(ctx, pl,"snadgrids").s;
-    if( nadgrids != NULL )
+    if( nadgrids != nullptr )
     {
         /* We don't actually save the value separately.  It will continue
            to exist int he param list for use in pj_apply_gridshift.c */
@@ -107,7 +107,7 @@ int pj_datum_set(projCtx ctx, paralist *pl, PJ *projdef)
 /* -------------------------------------------------------------------- */
 /*      Check for grid catalog parameter, and optional date.            */
 /* -------------------------------------------------------------------- */
-    else if( (catalog = pj_param(ctx, pl,"scatalog").s) != NULL )
+    else if( (catalog = pj_param(ctx, pl,"scatalog").s) != nullptr )
     {
         const char *date;
 
@@ -119,14 +119,14 @@ int pj_datum_set(projCtx ctx, paralist *pl, PJ *projdef)
         }
 
         date = pj_param(ctx, pl, "sdate").s;
-        if( date != NULL) 
+        if( date != nullptr) 
             projdef->datum_date = pj_gc_parsedate( ctx, date);
     }
 
 /* -------------------------------------------------------------------- */
 /*      Check for towgs84 parameter.                                    */
 /* -------------------------------------------------------------------- */
-    else if( (towgs84 = pj_param(ctx, pl,"stowgs84").s) != NULL )
+    else if( (towgs84 = pj_param(ctx, pl,"stowgs84").s) != nullptr )
     {
         int    parm_count = 0;
         const char *s;
diff --git a/src/pj_datums.c b/src/datums.cpp
index 2951b7bd..acbe12f7 100644
--- a/src/pj_datums.c
+++ b/src/datums.cpp
@@ -65,7 +65,7 @@ C_NAMESPACE_VAR const struct PJ_DATUMS pj_datums[] = {
                                                      "intl",  "New Zealand Geodetic Datum 1949"},
 {"OSGB36",  "towgs84=446.448,-125.157,542.060,0.1502,0.2470,0.8421,-20.4894",
                                                      "airy",  "Airy 1830"},
-{NULL,      NULL,                                    NULL,    NULL}
+{nullptr,      nullptr,                                    nullptr,    nullptr}
 };
 
 struct PJ_DATUMS *pj_get_datums_ref()
@@ -90,7 +90,7 @@ static const struct PJ_PRIME_MERIDIANS pj_prime_meridians[] = {
     {"athens",    "23d42'58.815\"E"},
     {"oslo",      "10d43'22.5\"E"},
     {"copenhagen","12d34'40.35\"E"},
-    {NULL,        NULL}
+    {nullptr,        nullptr}
 };
 
 const PJ_PRIME_MERIDIANS *proj_list_prime_meridians(void)
diff --git a/src/pj_deriv.c b/src/deriv.cpp
index 2c91e0cc..0e285265 100644
--- a/src/pj_deriv.c
+++ b/src/deriv.cpp
@@ -9,7 +9,7 @@ int pj_deriv(LP lp, double h, const PJ *P, struct DERIVS *der) {
     XY t;
     /* get rid of constness until we can do it for real */
     PJ *Q = (PJ *) P;
-    if (0==Q->fwd)
+    if (nullptr==Q->fwd)
         return 1;
 
     lp.lam += h;
diff --git a/src/dmstor.c b/src/dmstor.cpp
index ab8e33f4..967a9f18 100644
--- a/src/dmstor.c
+++ b/src/dmstor.cpp
@@ -27,7 +27,8 @@ dmstor(const char *is, char **rs) {
 	double
 dmstor_ctx(projCtx ctx, const char *is, char **rs) {
 	int sign, n, nl;
-	char *p, *s, work[MAX_WORK];
+	char *s, work[MAX_WORK];
+        const char* p;
 	double v, tv;
 
 	if (rs)
diff --git a/src/pj_ell_set.c b/src/ell_set.cpp
index e2d2750c..486230a5 100644
--- a/src/pj_ell_set.c
+++ b/src/ell_set.cpp
@@ -15,9 +15,9 @@ static int ellps_size (PJ *P);
 static int ellps_shape (PJ *P);
 static int ellps_spherification (PJ *P);
 
-static paralist *pj_get_param (paralist *list, char *key);
+static paralist *pj_get_param (paralist *list, const char *key);
 static char     *pj_param_value (paralist *list);
-static const PJ_ELLPS *pj_find_ellps (char *name);
+static const PJ_ELLPS *pj_find_ellps (const char *name);
 
 
 /***************************************************************************************/
@@ -75,9 +75,9 @@ int pj_ellipsoid (PJ *P) {
 
 ****************************************************************************************/
     int err = proj_errno_reset (P);
-    char *empty = {""};
+    const char *empty = {""};
 
-    P->def_size = P->def_shape = P->def_spherification = P->def_ellps = 0;
+    P->def_size = P->def_shape = P->def_spherification = P->def_ellps = nullptr;
 
     /* Specifying R overrules everything */
     if (pj_get_param (P->params, "R")) {
@@ -129,13 +129,13 @@ static int ellps_ellps (PJ *P) {
 /***************************************************************************************/
     PJ B;
     const PJ_ELLPS *ellps;
-    paralist *par = 0;
+    paralist *par = nullptr;
     char *name;
     int err;
 
     /* Sail home if ellps=xxx is not specified */
     par = pj_get_param (P->params, "ellps");
-    if (0==par)
+    if (nullptr==par)
         return 0;
 
     /* Otherwise produce a fake PJ to make ellps_size/ellps_shape do the hard work for us */
@@ -148,7 +148,7 @@ static int ellps_ellps (PJ *P) {
         return proj_errno_set (P, PJD_ERR_INVALID_ARG);
     name = par->param + 6;
     ellps = pj_find_ellps (name);
-    if (0==ellps)
+    if (nullptr==ellps)
         return proj_errno_set (P, PJD_ERR_UNKNOWN_ELLP_PARAM);
 
     /* Now, get things ready for ellps_size/ellps_shape, make them do their thing, and clean up */
@@ -178,7 +178,7 @@ static int ellps_ellps (PJ *P) {
 /***************************************************************************************/
 static int ellps_size (PJ *P) {
 /***************************************************************************************/
-    paralist *par = 0;
+    paralist *par = nullptr;
     int a_was_set = 0;
 
     /* A size parameter *must* be given, but may have been given as ellps prior */
@@ -187,9 +187,9 @@ static int ellps_size (PJ *P) {
 
     /* Check which size key is specified */
     par = pj_get_param (P->params, "R");
-    if (0==par)
+    if (nullptr==par)
         par = pj_get_param (P->params, "a");
-    if (0==par)
+    if (nullptr==par)
         return a_was_set? 0: proj_errno_set (P, PJD_ERR_MAJOR_AXIS_NOT_GIVEN);
 
     P->def_size = par->param;
@@ -211,12 +211,12 @@ static int ellps_size (PJ *P) {
 /***************************************************************************************/
 static int ellps_shape (PJ *P) {
 /***************************************************************************************/
-    char *keys[]  = {"rf", "f", "es", "e", "b"};
-    paralist *par = 0;
-    char *def = 0;
+    const char *keys[]  = {"rf", "f", "es", "e", "b"};
+    paralist *par = nullptr;
+    char *def = nullptr;
     size_t i, len;
 
-    par = 0;
+    par = nullptr;
     len = sizeof (keys) / sizeof (char *);
 
     /* Check which shape key is specified */
@@ -228,9 +228,9 @@ static int ellps_shape (PJ *P) {
 
     /* Not giving a shape parameter means selecting a sphere, unless shape */
     /* has been selected previously via ellps=xxx */
-    if (0==par && P->es != 0)
+    if (nullptr==par && P->es != 0)
         return 0;
-    if (0==par && P->es==0) {
+    if (nullptr==par && P->es==0) {
         P->es = P->f = 0;
         P->b = P->a;
         return 0;
@@ -317,16 +317,16 @@ static const double RV6   = 55/1296.;
 /***************************************************************************************/
 static int ellps_spherification (PJ *P) {
 /***************************************************************************************/
-    char *keys[] =  {"R_A", "R_V", "R_a", "R_g", "R_h", "R_lat_a", "R_lat_g"};
+    const char *keys[] =  {"R_A", "R_V", "R_a", "R_g", "R_h", "R_lat_a", "R_lat_g"};
     size_t len, i;
-    paralist *par = 0;
-    char *def = 0;
+    paralist *par = nullptr;
+    char *def = nullptr;
 
     double t;
     char *v, *endp;
 
     len = sizeof (keys) /  sizeof (char *);
-    P->def_spherification = 0;
+    P->def_spherification = nullptr;
 
     /* Check which spherification key is specified */
     for (i = 0;  i < len;  i++) {
@@ -400,7 +400,7 @@ static int ellps_spherification (PJ *P) {
 
 
 /* locate parameter in list */
-static paralist *pj_get_param (paralist *list, char *key) {
+static paralist *pj_get_param (paralist *list, const char *key) {
     size_t l = strlen(key);
 	while (list && !(0==strncmp(list->param, key, l) && (0==list->param[l] || list->param[l] == '=') ) )
 		list = list->next;
@@ -410,8 +410,8 @@ static paralist *pj_get_param (paralist *list, char *key) {
 
 static char *pj_param_value (paralist *list) {
     char *key, *value;
-    if (0==list)
-        return 0;
+    if (nullptr==list)
+        return nullptr;
 
     key = list->param;
     value = strchr (key, '=');
@@ -421,20 +421,20 @@ static char *pj_param_value (paralist *list) {
 }
 
 
-static const PJ_ELLPS *pj_find_ellps (char *name) {
+static const PJ_ELLPS *pj_find_ellps (const char *name) {
     int i;
     const char *s;
     const PJ_ELLPS *ellps;
 
-    if (0==name)
-        return 0;
+    if (nullptr==name)
+        return nullptr;
 
     ellps = proj_list_ellps();
 
     /* Search through internal ellipsoid list for name */
     for (i = 0; (s = ellps[i].id) && strcmp(name, s) ; ++i);
-    if (0==s)
-        return 0;
+    if (nullptr==s)
+        return nullptr;
     return ellps + i;
 }
 
diff --git a/src/pj_ellps.c b/src/ellps.cpp
index 8b3b8f0a..f548d30d 100644
--- a/src/pj_ellps.c
+++ b/src/ellps.cpp
@@ -53,7 +53,7 @@ pj_ellps[] = {
 {"WGS72",	"a=6378135.0",		"rf=298.26", 		"WGS 72"},
 {"WGS84",	"a=6378137.0",		"rf=298.257223563",	"WGS 84"},
 {"sphere",	"a=6370997.0",		"b=6370997.0",		"Normal Sphere (r=6370997)"},
-{NULL,		NULL,			NULL,			NULL}
+{nullptr,		nullptr,			nullptr,			nullptr}
 };
 
 const PJ_ELLPS *proj_list_ellps(void)
diff --git a/src/pj_errno.c b/src/errno.cpp
index 6e98cd73..f6ea9bfc 100644
--- a/src/pj_errno.c
+++ b/src/errno.cpp
@@ -2,7 +2,7 @@
 
 #include "projects.h"
 
-C_NAMESPACE_VAR int pj_errno = 0;
+int pj_errno = 0;
 
 /************************************************************************/
 /*                          pj_get_errno_ref()                          */
diff --git a/src/pj_factors.c b/src/factors.cpp
index e4b871a1..768bf585 100644
--- a/src/pj_factors.c
+++ b/src/factors.cpp
@@ -21,10 +21,10 @@ int pj_factors(LP lp, const PJ *P, double h, struct FACTORS *fac) {
 
     /* Failing the 3 initial checks will most likely be due to */
     /* earlier errors, so we leave errno alone */
-    if (0==fac)
+    if (nullptr==fac)
         return 1;
 
-    if (0==P)
+    if (nullptr==P)
         return 1;
 
     if (HUGE_VAL==lp.lam)
diff --git a/src/pj_fileapi.c b/src/fileapi.cpp
index eba96afd..3df73236 100644
--- a/src/pj_fileapi.c
+++ b/src/fileapi.cpp
@@ -75,9 +75,9 @@ static PAFile stdio_fopen(projCtx ctx, const char *filename,
     FILE *fp;
 
     fp = fopen(filename, access);
-    if (fp == NULL)
+    if (fp == nullptr)
     {
-        return NULL;
+        return nullptr;
     }
 
     pafile = (stdio_pafile *) malloc(sizeof(stdio_pafile));
@@ -85,7 +85,7 @@ static PAFile stdio_fopen(projCtx ctx, const char *filename,
     {
         pj_ctx_set_errno(ctx, ENOMEM);
         fclose(fp);
-        return NULL;
+        return nullptr;
     }
 
     pafile->fp = fp;
@@ -193,7 +193,7 @@ char *pj_ctx_fgets(projCtx ctx, char *line, int size, PAFile file)
     line[size-1] = '\0';
     bytes_read = pj_ctx_fread(ctx, line, 1, size-1, file);
     if(bytes_read == 0)
-        return NULL;
+        return nullptr;
     if(bytes_read < (size_t)size)
     {
         line[bytes_read] = '\0';
diff --git a/src/pj_fwd.c b/src/fwd.cpp
index 38443f07..e8f73999 100644
--- a/src/pj_fwd.c
+++ b/src/fwd.cpp
@@ -74,7 +74,7 @@ static PJ_COORD fwd_prepare (PJ *P, PJ_COORD coo) {
 
         if (P->hgridshift)
             coo = proj_trans (P->hgridshift, PJ_INV, coo);
-        else if (P->helmert || (P->cart_wgs84 != 0 && P->cart != 0)) {
+        else if (P->helmert || (P->cart_wgs84 != nullptr && P->cart != nullptr)) {
             coo = proj_trans (P->cart_wgs84, PJ_FWD, coo); /* Go cartesian in WGS84 frame */
             if( P->helmert )
                 coo = proj_trans (P->helmert,    PJ_INV, coo); /* Step into local frame */
diff --git a/src/pj_gauss.c b/src/gauss.cpp
index 4520bb39..2db713ad 100644
--- a/src/pj_gauss.c
+++ b/src/gauss.cpp
@@ -32,12 +32,14 @@
 
 #define MAX_ITER 20
 
+namespace { // anonymous namespace
 struct GAUSS {
     double C;
     double K;
     double e;
     double ratexp;
 };
+} // anonymous namespace
 #define DEL_TOL 1e-14
 
 static double srat(double esinp, double ratexp) {
@@ -48,8 +50,8 @@ void *pj_gauss_ini(double e, double phi0, double *chi, double *rc) {
     double sphi, cphi, es;
     struct GAUSS *en;
 
-    if ((en = (struct GAUSS *)malloc(sizeof(struct GAUSS))) == NULL)
-        return (NULL);
+    if ((en = (struct GAUSS *)malloc(sizeof(struct GAUSS))) == nullptr)
+        return (nullptr);
     es = e * e;
     en->e = e;
     sphi = sin(phi0);
@@ -58,7 +60,7 @@ void *pj_gauss_ini(double e, double phi0, double *chi, double *rc) {
     en->C = sqrt(1. + es * cphi * cphi / (1. - es));
     if (en->C == 0.0) {
         free(en);
-        return NULL;
+        return nullptr;
     }
     *chi = asin(sphi / en->C);
     en->ratexp = 0.5 * en->C * e;
diff --git a/src/pj_gc_reader.c b/src/gc_reader.cpp
index 493fc075..118aadf6 100644
--- a/src/pj_gc_reader.c
+++ b/src/gc_reader.cpp
@@ -50,8 +50,8 @@ PJ_GridCatalog *pj_gc_readcatalog( projCtx ctx, const char *catalog_name )
     char line[302];
 
     fid = pj_open_lib( ctx, catalog_name, "r" );
-    if (fid == NULL) 
-        return NULL;
+    if (fid == nullptr) 
+        return nullptr;
 
     /* discard title line */
     pj_ctx_fgets(ctx, line, sizeof(line)-1, fid);
@@ -61,7 +61,7 @@ PJ_GridCatalog *pj_gc_readcatalog( projCtx ctx, const char *catalog_name )
     {
         pj_ctx_set_errno(ctx, ENOMEM);
         pj_ctx_fclose(ctx, fid);
-        return NULL;
+        return nullptr;
     }
     
     catalog->catalog_name = pj_strdup(catalog_name);
@@ -69,7 +69,7 @@ PJ_GridCatalog *pj_gc_readcatalog( projCtx ctx, const char *catalog_name )
         pj_ctx_set_errno(ctx, ENOMEM);
         free(catalog);
         pj_ctx_fclose(ctx, fid);
-        return NULL;
+        return nullptr;
     }
     
     entry_max = 10;
@@ -80,7 +80,7 @@ PJ_GridCatalog *pj_gc_readcatalog( projCtx ctx, const char *catalog_name )
         free(catalog->catalog_name);
         free(catalog);
         pj_ctx_fclose(ctx, fid);
-        return NULL;
+        return nullptr;
     }
     
     while( gc_readentry( ctx, fid, 
@@ -95,7 +95,7 @@ PJ_GridCatalog *pj_gc_readcatalog( projCtx ctx, const char *catalog_name )
             new_entries = (PJ_GridCatalogEntry *) 
                 realloc(catalog->entries, 
                         entry_max * sizeof(PJ_GridCatalogEntry));
-            if (new_entries == NULL )
+            if (new_entries == nullptr )
             {
                 int i;
                 for( i = 0; i < catalog->entry_count; i++ )
@@ -104,7 +104,7 @@ PJ_GridCatalog *pj_gc_readcatalog( projCtx ctx, const char *catalog_name )
                 free( catalog->catalog_name );
                 free( catalog );
                 pj_ctx_fclose(ctx, fid);
-                return NULL;
+                return nullptr;
             }
             catalog->entries = new_entries;
         }
@@ -127,7 +127,7 @@ static int gc_read_csv_line( projCtx ctx, PAFile fid,
 {
     char line[302];
    
-    while( pj_ctx_fgets(ctx, line, sizeof(line)-1, fid) != NULL )
+    while( pj_ctx_fgets(ctx, line, sizeof(line)-1, fid) != nullptr )
     {
         char *next = line;
         int token_count = 0;
@@ -226,11 +226,11 @@ static int gc_readentry(projCtx ctx, PAFile fid, PJ_GridCatalogEntry *entry)
     else
     {
         entry->definition = tokens[0];
-        tokens[0] = NULL;   /* We take ownership of tokens[0] */
-        entry->region.ll_long = dmstor_ctx( ctx, tokens[1], NULL );
-        entry->region.ll_lat = dmstor_ctx( ctx, tokens[2], NULL );
-        entry->region.ur_long = dmstor_ctx( ctx, tokens[3], NULL );
-        entry->region.ur_lat = dmstor_ctx( ctx, tokens[4], NULL );
+        tokens[0] = nullptr;   /* We take ownership of tokens[0] */
+        entry->region.ll_long = dmstor_ctx( ctx, tokens[1], nullptr );
+        entry->region.ll_lat = dmstor_ctx( ctx, tokens[2], nullptr );
+        entry->region.ur_long = dmstor_ctx( ctx, tokens[3], nullptr );
+        entry->region.ur_lat = dmstor_ctx( ctx, tokens[4], nullptr );
         if( token_count > 5 )
             entry->priority = atoi( tokens[5] ); /* defaults to zero */
         if( token_count > 6 )
diff --git a/src/geocent.c b/src/geocent.cpp
index c023bdd3..c023bdd3 100644
--- a/src/geocent.c
+++ b/src/geocent.cpp
diff --git a/src/geodesic.c b/src/geodesic.c
index 220dcd7f..5504cb3b 100644
--- a/src/geodesic.c
+++ b/src/geodesic.c
@@ -34,6 +34,10 @@
 #define HAVE_C99_MATH 0
 #endif
 
+#if !defined(__cplusplus)
+#define nullptr 0
+#endif
+
 #define GEOGRAPHICLIB_GEODESIC_ORDER 6
 #define nA1   GEOGRAPHICLIB_GEODESIC_ORDER
 #define nC1   GEOGRAPHICLIB_GEODESIC_ORDER
@@ -507,13 +511,13 @@ real geod_genposition(const struct geod_geodesicline* l,
   real omg12, lam12, lon12;
   real ssig2, csig2, sbet2, cbet2, somg2, comg2, salp2, calp2, dn2;
   unsigned outmask =
-    (plat2 ? GEOD_LATITUDE : 0U) |
-    (plon2 ? GEOD_LONGITUDE : 0U) |
-    (pazi2 ? GEOD_AZIMUTH : 0U) |
-    (ps12 ? GEOD_DISTANCE : 0U) |
-    (pm12 ? GEOD_REDUCEDLENGTH : 0U) |
-    (pM12 || pM21 ? GEOD_GEODESICSCALE : 0U) |
-    (pS12 ? GEOD_AREA : 0U);
+    (plat2 ? GEOD_LATITUDE : GEOD_NONE) |
+    (plon2 ? GEOD_LONGITUDE : GEOD_NONE) |
+    (pazi2 ? GEOD_AZIMUTH : GEOD_NONE) |
+    (ps12 ? GEOD_DISTANCE : GEOD_NONE) |
+    (pm12 ? GEOD_REDUCEDLENGTH : GEOD_NONE) |
+    (pM12 || pM21 ? GEOD_GEODESICSCALE : GEOD_NONE) |
+    (pS12 ? GEOD_AREA : GEOD_NONE);
 
   outmask &= l->caps & OUT_ALL;
   if (!( TRUE /*Init()*/ &&
@@ -693,12 +697,12 @@ real geod_genposition(const struct geod_geodesicline* l,
 
 void geod_setdistance(struct geod_geodesicline* l, real s13) {
   l->s13 = s13;
-  l->a13 = geod_genposition(l, GEOD_NOFLAGS, l->s13, 0, 0, 0, 0, 0, 0, 0, 0);
+  l->a13 = geod_genposition(l, GEOD_NOFLAGS, l->s13, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr);
 }
 
 static void geod_setarc(struct geod_geodesicline* l, real a13) {
   l->a13 = a13; l->s13 = NaN;
-  geod_genposition(l, GEOD_ARCMODE, l->a13, 0, 0, 0, &l->s13, 0, 0, 0, 0);
+  geod_genposition(l, GEOD_ARCMODE, l->a13, nullptr, nullptr, nullptr, &l->s13, nullptr, nullptr, nullptr, nullptr);
 }
 
 void geod_gensetdistance(struct geod_geodesicline* l,
@@ -710,7 +714,7 @@ void geod_gensetdistance(struct geod_geodesicline* l,
 
 void geod_position(const struct geod_geodesicline* l, real s12,
                    real* plat2, real* plon2, real* pazi2) {
-  geod_genposition(l, FALSE, s12, plat2, plon2, pazi2, 0, 0, 0, 0, 0);
+  geod_genposition(l, FALSE, s12, plat2, plon2, pazi2, nullptr, nullptr, nullptr, nullptr, nullptr);
 }
 
 real geod_gendirect(const struct geod_geodesic* g,
@@ -721,13 +725,13 @@ real geod_gendirect(const struct geod_geodesic* g,
                     real* pS12) {
   struct geod_geodesicline l;
   unsigned outmask =
-    (plat2 ? GEOD_LATITUDE : 0U) |
-    (plon2 ? GEOD_LONGITUDE : 0U) |
-    (pazi2 ? GEOD_AZIMUTH : 0U) |
-    (ps12 ? GEOD_DISTANCE : 0U) |
-    (pm12 ? GEOD_REDUCEDLENGTH : 0U) |
-    (pM12 || pM21 ? GEOD_GEODESICSCALE : 0U) |
-    (pS12 ? GEOD_AREA : 0U);
+    (plat2 ? GEOD_LATITUDE : GEOD_NONE) |
+    (plon2 ? GEOD_LONGITUDE : GEOD_NONE) |
+    (pazi2 ? GEOD_AZIMUTH : GEOD_NONE) |
+    (ps12 ? GEOD_DISTANCE : GEOD_NONE) |
+    (pm12 ? GEOD_REDUCEDLENGTH : GEOD_NONE) |
+    (pM12 || pM21 ? GEOD_GEODESICSCALE : GEOD_NONE) |
+    (pS12 ? GEOD_AREA : GEOD_NONE);
 
   geod_lineinit(&l, g, lat1, lon1, azi1,
                 /* Automatically supply GEOD_DISTANCE_IN if necessary */
@@ -742,7 +746,7 @@ void geod_direct(const struct geod_geodesic* g,
                  real s12,
                  real* plat2, real* plon2, real* pazi2) {
   geod_gendirect(g, lat1, lon1, azi1, GEOD_NOFLAGS, s12, plat2, plon2, pazi2,
-                 0, 0, 0, 0, 0);
+                 nullptr, nullptr, nullptr, nullptr, nullptr);
 }
 
 static real geod_geninverse_int(const struct geod_geodesic* g,
@@ -764,10 +768,10 @@ static real geod_geninverse_int(const struct geod_geodesic* g,
   real omg12 = 0, somg12 = 2, comg12 = 0;
 
   unsigned outmask =
-    (ps12 ? GEOD_DISTANCE : 0U) |
-    (pm12 ? GEOD_REDUCEDLENGTH : 0U) |
-    (pM12 || pM21 ? GEOD_GEODESICSCALE : 0U) |
-    (pS12 ? GEOD_AREA : 0U);
+    (ps12 ? GEOD_DISTANCE : GEOD_NONE) |
+    (pm12 ? GEOD_REDUCEDLENGTH : GEOD_NONE) |
+    (pM12 || pM21 ? GEOD_GEODESICSCALE : GEOD_NONE) |
+    (pS12 ? GEOD_AREA : GEOD_NONE);
 
   outmask &= OUT_ALL;
   /* Compute longitude difference (AngDiff does this carefully).  Result is
@@ -858,9 +862,9 @@ static real geod_geninverse_int(const struct geod_geodesic* g,
     sig12 = atan2(maxx((real)(0), csig1 * ssig2 - ssig1 * csig2),
                                   csig1 * csig2 + ssig1 * ssig2);
     Lengths(g, g->n, sig12, ssig1, csig1, dn1, ssig2, csig2, dn2,
-            cbet1, cbet2, &s12x, &m12x, 0,
-            (outmask & GEOD_GEODESICSCALE) ? &M12 : 0,
-            (outmask & GEOD_GEODESICSCALE) ? &M21 : 0,
+            cbet1, cbet2, &s12x, &m12x, nullptr,
+            (outmask & GEOD_GEODESICSCALE) ? &M12 : nullptr,
+            (outmask & GEOD_GEODESICSCALE) ? &M21 : nullptr,
             Ca);
     /* Add the check for sig12 since zero length geodesics might yield m12 <
      * 0.  Test case was
@@ -983,9 +987,9 @@ static real geod_geninverse_int(const struct geod_geodesic* g,
                  fabs(salp1 - salp1b) + (calp1 - calp1b) < tolb);
       }
       Lengths(g, eps, sig12, ssig1, csig1, dn1, ssig2, csig2, dn2,
-              cbet1, cbet2, &s12x, &m12x, 0,
-              (outmask & GEOD_GEODESICSCALE) ? &M12 : 0,
-              (outmask & GEOD_GEODESICSCALE) ? &M21 : 0, Ca);
+              cbet1, cbet2, &s12x, &m12x, nullptr,
+              (outmask & GEOD_GEODESICSCALE) ? &M12 : nullptr,
+              (outmask & GEOD_GEODESICSCALE) ? &M21 : nullptr, Ca);
       m12x *= g->b;
       s12x *= g->b;
       a12 = sig12 / degree;
@@ -1115,9 +1119,9 @@ void geod_inverseline(struct geod_geodesicline* l,
                       real lat1, real lon1, real lat2, real lon2,
                       unsigned caps) {
   real salp1, calp1,
-    a12 = geod_geninverse_int(g, lat1, lon1, lat2, lon2, 0,
-                              &salp1, &calp1, 0, 0,
-                              0, 0, 0, 0),
+    a12 = geod_geninverse_int(g, lat1, lon1, lat2, lon2, nullptr,
+                              &salp1, &calp1, nullptr, nullptr,
+                              nullptr, nullptr, nullptr, nullptr),
     azi1 = atan2dx(salp1, calp1);
   caps = caps ? caps : GEOD_DISTANCE_IN | GEOD_LONGITUDE;
   /* Ensure that a12 can be converted to a distance */
@@ -1129,7 +1133,7 @@ void geod_inverseline(struct geod_geodesicline* l,
 void geod_inverse(const struct geod_geodesic* g,
                   real lat1, real lon1, real lat2, real lon2,
                   real* ps12, real* pazi1, real* pazi2) {
-  geod_geninverse(g, lat1, lon1, lat2, lon2, ps12, pazi1, pazi2, 0, 0, 0, 0);
+  geod_geninverse(g, lat1, lon1, lat2, lon2, ps12, pazi1, pazi2, nullptr, nullptr, nullptr, nullptr);
 }
 
 real SinCosSeries(boolx sinp, real sinx, real cosx, const real c[], int n) {
@@ -1371,7 +1375,7 @@ real InverseStart(const struct geod_geodesic* g,
        * Inverse. */
       Lengths(g, g->n, pi + bet12a,
               sbet1, -cbet1, dn1, sbet2, cbet2, dn2,
-              cbet1, cbet2, 0, &m12b, &m0, 0, 0, Ca);
+              cbet1, cbet2, nullptr, &m12b, &m0, nullptr, nullptr, Ca);
       x = -1 + m12b / (cbet1 * cbet2 * m0 * pi);
       betscale = x < -(real)(0.01) ? sbet12a / x :
         -g->f * sq(cbet1) * pi;
@@ -1531,7 +1535,7 @@ real Lambda12(const struct geod_geodesic* g,
       dlam12 = - 2 * g->f1 * dn1 / sbet1;
     else {
       Lengths(g, eps, sig12, ssig1, csig1, dn1, ssig2, csig2, dn2,
-              cbet1, cbet2, 0, &dlam12, 0, 0, 0, Ca);
+              cbet1, cbet2, nullptr, &dlam12, nullptr, nullptr, nullptr, Ca);
       dlam12 *= g->f1 / (calp2 * cbet2);
     }
   }
@@ -1819,7 +1823,7 @@ int transit(real lon1, real lon2) {
   /* Compute lon12 the same way as Geodesic::Inverse. */
   lon1 = AngNormalize(lon1);
   lon2 = AngNormalize(lon2);
-  lon12 = AngDiff(lon1, lon2, 0);
+  lon12 = AngDiff(lon1, lon2, nullptr);
   return lon1 <= 0 && lon2 > 0 && lon12 > 0 ? 1 :
     (lon2 <= 0 && lon1 > 0 && lon12 < 0 ? -1 : 0);
 }
@@ -1893,7 +1897,7 @@ void geod_polygon_addpoint(const struct geod_geodesic* g,
   } else {
     real s12, S12 = 0;       /* Initialize S12 to stop Visual Studio warning */
     geod_geninverse(g, p->lat, p->lon, lat, lon,
-                    &s12, 0, 0, 0, 0, 0, p->polyline ? 0 : &S12);
+                    &s12, nullptr, nullptr, nullptr, nullptr, nullptr, p->polyline ? nullptr : &S12);
     accadd(p->P, s12);
     if (!p->polyline) {
       accadd(p->A, S12);
@@ -1912,8 +1916,8 @@ void geod_polygon_addedge(const struct geod_geodesic* g,
      * lon is to make CLang static analyzer happy. */
     real lat = 0, lon = 0, S12 = 0;
     geod_gendirect(g, p->lat, p->lon, azi, GEOD_LONG_UNROLL, s,
-                   &lat, &lon, 0,
-                   0, 0, 0, 0, p->polyline ? 0 : &S12);
+                   &lat, &lon, nullptr,
+                   nullptr, nullptr, nullptr, nullptr, p->polyline ? nullptr : &S12);
     accadd(p->P, s);
     if (!p->polyline) {
       accadd(p->A, S12);
@@ -1940,7 +1944,7 @@ unsigned geod_polygon_compute(const struct geod_geodesic* g,
     return p->num;
   }
   geod_geninverse(g, p->lat, p->lon, p->lat0, p->lon0,
-                  &s12, 0, 0, 0, 0, 0, &S12);
+                  &s12, nullptr, nullptr, nullptr, nullptr, nullptr, &S12);
   if (pP) *pP = accsum(p->P, s12);
   acccopy(p->A, t);
   accadd(t, S12);
@@ -1989,7 +1993,7 @@ unsigned geod_polygon_testpoint(const struct geod_geodesic* g,
     geod_geninverse(g,
                     i == 0 ? p->lat  : lat, i == 0 ? p->lon  : lon,
                     i != 0 ? p->lat0 : lat, i != 0 ? p->lon0 : lon,
-                    &s12, 0, 0, 0, 0, 0, p->polyline ? 0 : &S12);
+                    &s12, nullptr, nullptr, nullptr, nullptr, nullptr, p->polyline ? nullptr : &S12);
     perimeter += s12;
     if (!p->polyline) {
       tempsum += S12;
@@ -2051,12 +2055,12 @@ unsigned geod_polygon_testedge(const struct geod_geodesic* g,
        happy. */
     real lat = 0, lon = 0, s12, S12 = 0;
     geod_gendirect(g, p->lat, p->lon, azi, GEOD_LONG_UNROLL, s,
-                   &lat, &lon, 0,
-                   0, 0, 0, 0, &S12);
+                   &lat, &lon, nullptr,
+                   nullptr, nullptr, nullptr, nullptr, &S12);
     tempsum += S12;
     crossings += transitdirect(p->lon, lon);
     geod_geninverse(g, lat,  lon, p->lat0,  p->lon0,
-                    &s12, 0, 0, 0, 0, 0, &S12);
+                    &s12, nullptr, nullptr, nullptr, nullptr, nullptr, &S12);
     perimeter += s12;
     tempsum += S12;
     crossings += transit(lon, p->lon0);
diff --git a/src/pj_gridcatalog.c b/src/gridcatalog.cpp
index ea9c4aa1..fef2df56 100644
--- a/src/pj_gridcatalog.c
+++ b/src/gridcatalog.cpp
@@ -34,7 +34,7 @@
 
 #include "projects.h"
 
-static PJ_GridCatalog *grid_catalog_list = NULL;
+static PJ_GridCatalog *grid_catalog_list = nullptr;
 
 /************************************************************************/
 /*                          pj_gc_unloadall()                           */
@@ -47,7 +47,7 @@ void pj_gc_unloadall( projCtx ctx )
 {
     (void) ctx;
 
-    while( grid_catalog_list != NULL )
+    while( grid_catalog_list != nullptr )
     {
         int i;
         PJ_GridCatalog *catalog = grid_catalog_list;
@@ -75,7 +75,7 @@ PJ_GridCatalog *pj_gc_findcatalog( projCtx ctx, const char *name )
 
     pj_acquire_lock();
 
-    for( catalog=grid_catalog_list; catalog != NULL; catalog = catalog->next ) 
+    for( catalog=grid_catalog_list; catalog != nullptr; catalog = catalog->next ) 
     {
         if( strcmp(catalog->catalog_name, name) == 0 )
         {
@@ -87,8 +87,8 @@ PJ_GridCatalog *pj_gc_findcatalog( projCtx ctx, const char *name )
     pj_release_lock();
 
     catalog = pj_gc_readcatalog( ctx, name );
-    if( catalog == NULL )
-        return NULL;
+    if( catalog == nullptr )
+        return nullptr;
 
     pj_acquire_lock();
     catalog->next = grid_catalog_list;
@@ -110,10 +110,10 @@ int pj_gc_apply_gridshift( PJ *defn, int inverse,
     int i;
     (void) z;
 
-    if( defn->catalog == NULL ) 
+    if( defn->catalog == nullptr ) 
     {
         defn->catalog = pj_gc_findcatalog( defn->ctx, defn->catalog_name );
-        if( defn->catalog == NULL )
+        if( defn->catalog == nullptr )
             return defn->ctx->last_errno;
     }
 
@@ -130,7 +130,7 @@ int pj_gc_apply_gridshift( PJ *defn, int inverse,
         input.lam = x[io];
 
         /* make sure we have appropriate "after" shift file available */
-        if( defn->last_after_grid == NULL
+        if( defn->last_after_grid == nullptr
             || input.lam < defn->last_after_region.ll_long
             || input.lam > defn->last_after_region.ur_long
             || input.phi < defn->last_after_region.ll_lat
@@ -140,17 +140,17 @@ int pj_gc_apply_gridshift( PJ *defn, int inverse,
                                 1, input, defn->datum_date, 
                                 &(defn->last_after_region), 
                                 &(defn->last_after_date));
-            if( defn->last_after_grid == NULL )
+            if( defn->last_after_grid == nullptr )
             {
                 pj_ctx_set_errno( defn->ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
                 return PJD_ERR_FAILED_TO_LOAD_GRID;
             }
         }
         gi = defn->last_after_grid;
-        assert( gi->child == NULL );
+        assert( gi->child == nullptr );
 
         /* load the grid shift info if we don't have it. */
-        if( gi->ct->cvs == NULL && !pj_gridinfo_load( defn->ctx, gi ) )
+        if( gi->ct->cvs == nullptr && !pj_gridinfo_load( defn->ctx, gi ) )
         {
             pj_ctx_set_errno( defn->ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
             return PJD_ERR_FAILED_TO_LOAD_GRID;
@@ -178,7 +178,7 @@ int pj_gc_apply_gridshift( PJ *defn, int inverse,
         }
 
         /* make sure we have appropriate "before" shift file available */
-        if( defn->last_before_grid == NULL
+        if( defn->last_before_grid == nullptr
             || input.lam < defn->last_before_region.ll_long
             || input.lam > defn->last_before_region.ur_long
             || input.phi < defn->last_before_region.ll_lat
@@ -188,7 +188,7 @@ int pj_gc_apply_gridshift( PJ *defn, int inverse,
                                 0, input, defn->datum_date, 
                                 &(defn->last_before_region), 
                                 &(defn->last_before_date));
-            if( defn->last_before_grid == NULL )
+            if( defn->last_before_grid == nullptr )
             {
                 pj_ctx_set_errno( defn->ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
                 return PJD_ERR_FAILED_TO_LOAD_GRID;
@@ -196,10 +196,10 @@ int pj_gc_apply_gridshift( PJ *defn, int inverse,
         }
 
         gi = defn->last_before_grid;
-        assert( gi->child == NULL );
+        assert( gi->child == nullptr );
 
         /* load the grid shift info if we don't have it. */
-        if( gi->ct->cvs == NULL && !pj_gridinfo_load( defn->ctx, gi ) )
+        if( gi->ct->cvs == nullptr && !pj_gridinfo_load( defn->ctx, gi ) )
         {
             pj_ctx_set_errno( defn->ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
             return PJD_ERR_FAILED_TO_LOAD_GRID;
@@ -241,7 +241,7 @@ PJ_GRIDINFO *pj_gc_findgrid( projCtx ctx, PJ_GridCatalog *catalog, int after,
                              double *grid_date ) 
 {
     int iEntry;
-    PJ_GridCatalogEntry *entry = NULL;
+    PJ_GridCatalogEntry *entry = nullptr;
 
     for( iEntry = 0; iEntry < catalog->entry_count; iEntry++ ) 
     {
@@ -263,13 +263,13 @@ PJ_GRIDINFO *pj_gc_findgrid( projCtx ctx, PJ_GridCatalog *catalog, int after,
         break;
     }
 
-    if( entry == NULL )
+    if( entry == nullptr )
     {
         if( grid_date )
             *grid_date = 0.0;
-        if( optional_region != NULL )
+        if( optional_region != nullptr )
             memset( optional_region, 0, sizeof(PJ_Region));
-        return NULL;
+        return nullptr;
     }
 
     if( grid_date )
@@ -280,9 +280,9 @@ PJ_GRIDINFO *pj_gc_findgrid( projCtx ctx, PJ_GridCatalog *catalog, int after,
         
     }
 
-    if( entry->gridinfo == NULL )
+    if( entry->gridinfo == nullptr )
     {
-        PJ_GRIDINFO **gridlist = NULL;
+        PJ_GRIDINFO **gridlist = nullptr;
         int grid_count = 0;
         gridlist = pj_gridlist_from_nadgrids( ctx, entry->definition, 
                                               &grid_count);
diff --git a/src/pj_gridinfo.c b/src/gridinfo.cpp
index de0e8d31..046abfcc 100644
--- a/src/pj_gridinfo.c
+++ b/src/gridinfo.cpp
@@ -89,25 +89,25 @@ static double to_double( unsigned char* data )
 void pj_gridinfo_free( projCtx ctx, PJ_GRIDINFO *gi )
 
 {
-    if( gi == NULL )
+    if( gi == nullptr )
         return;
 
-    if( gi->child != NULL )
+    if( gi->child != nullptr )
     {
         PJ_GRIDINFO *child, *next;
 
-        for( child = gi->child; child != NULL; child=next)
+        for( child = gi->child; child != nullptr; child=next)
         {
             next=child->next;
             pj_gridinfo_free( ctx, child );
         }
     }
 
-    if( gi->ct != NULL )
+    if( gi->ct != nullptr )
         nad_free( gi->ct );
 
     free( gi->gridname );
-    if( gi->filename != NULL )
+    if( gi->filename != nullptr )
         free( gi->filename );
 
     pj_dalloc( gi );
@@ -126,11 +126,11 @@ int pj_gridinfo_load( projCtx ctx, PJ_GRIDINFO *gi )
 {
     struct CTABLE ct_tmp;
 
-    if( gi == NULL || gi->ct == NULL )
+    if( gi == nullptr || gi->ct == nullptr )
         return 0;
 
     pj_acquire_lock();
-    if( gi->ct->cvs != NULL )
+    if( gi->ct->cvs != nullptr )
     {
         pj_release_lock();
         return 1;
@@ -148,7 +148,7 @@ int pj_gridinfo_load( projCtx ctx, PJ_GRIDINFO *gi )
 
         fid = pj_open_lib( ctx, gi->filename, "rb" );
 
-        if( fid == NULL )
+        if( fid == nullptr )
         {
             pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
             pj_release_lock();
@@ -175,7 +175,7 @@ int pj_gridinfo_load( projCtx ctx, PJ_GRIDINFO *gi )
 
         fid = pj_open_lib( ctx, gi->filename, "rb" );
 
-        if( fid == NULL )
+        if( fid == nullptr )
         {
             pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
             pj_release_lock();
@@ -207,7 +207,7 @@ int pj_gridinfo_load( projCtx ctx, PJ_GRIDINFO *gi )
 
         fid = pj_open_lib( ctx, gi->filename, "rb" );
 
-        if( fid == NULL )
+        if( fid == nullptr )
         {
             pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
             pj_release_lock();
@@ -218,7 +218,7 @@ int pj_gridinfo_load( projCtx ctx, PJ_GRIDINFO *gi )
 
         row_buf = (double *) pj_malloc(gi->ct->lim.lam * sizeof(double) * 2);
         ct_tmp.cvs = (FLP *) pj_malloc(gi->ct->lim.lam*gi->ct->lim.phi*sizeof(FLP));
-        if( row_buf == NULL || ct_tmp.cvs == NULL )
+        if( row_buf == nullptr || ct_tmp.cvs == nullptr )
         {
             pj_dalloc( row_buf );
             pj_dalloc( ct_tmp.cvs );
@@ -288,7 +288,7 @@ int pj_gridinfo_load( projCtx ctx, PJ_GRIDINFO *gi )
 
         fid = pj_open_lib( ctx, gi->filename, "rb" );
 
-        if( fid == NULL )
+        if( fid == nullptr )
         {
             pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
             pj_release_lock();
@@ -299,7 +299,7 @@ int pj_gridinfo_load( projCtx ctx, PJ_GRIDINFO *gi )
 
         row_buf = (float *) pj_malloc(gi->ct->lim.lam * sizeof(float) * 4);
         ct_tmp.cvs = (FLP *) pj_malloc(gi->ct->lim.lam*gi->ct->lim.phi*sizeof(FLP));
-        if( row_buf == NULL || ct_tmp.cvs == NULL )
+        if( row_buf == nullptr || ct_tmp.cvs == nullptr )
         {
             pj_dalloc( row_buf );
             pj_dalloc( ct_tmp.cvs );
@@ -363,7 +363,7 @@ int pj_gridinfo_load( projCtx ctx, PJ_GRIDINFO *gi )
 
         fid = pj_open_lib( ctx, gi->filename, "rb" );
 
-        if( fid == NULL )
+        if( fid == nullptr )
         {
             pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
             pj_release_lock();
@@ -373,7 +373,7 @@ int pj_gridinfo_load( projCtx ctx, PJ_GRIDINFO *gi )
         pj_ctx_fseek( ctx, fid, gi->grid_offset, SEEK_SET );
 
         ct_tmp.cvs = (FLP *) pj_malloc(words*sizeof(float));
-        if( ct_tmp.cvs == NULL )
+        if( ct_tmp.cvs == nullptr )
         {
             pj_ctx_set_errno( ctx, ENOMEM );
             pj_release_lock();
@@ -563,7 +563,7 @@ static int pj_gridinfo_init_ntv2( projCtx ctx, PAFile fid, PJ_GRIDINFO *gilist )
             return 0;
         }
 
-        ct->cvs = NULL;
+        ct->cvs = nullptr;
 
 /* -------------------------------------------------------------------- */
 /*      Create a new gridinfo for this if we aren't processing the      */
@@ -590,7 +590,7 @@ static int pj_gridinfo_init_ntv2( projCtx ctx, PAFile fid, PJ_GRIDINFO *gilist )
                 pj_ctx_set_errno(ctx, ENOMEM);
                 return 0;
             }
-            gi->next = NULL;
+            gi->next = nullptr;
         }
 
         gi->must_swap = must_swap;
@@ -607,7 +607,7 @@ static int pj_gridinfo_init_ntv2( projCtx ctx, PAFile fid, PJ_GRIDINFO *gilist )
             {
                 PJ_GRIDINFO *lnk;
 
-                for( lnk = gilist; lnk->next != NULL; lnk = lnk->next ) {}
+                for( lnk = gilist; lnk->next != nullptr; lnk = lnk->next ) {}
                 lnk->next = gi;
             }
         }
@@ -618,25 +618,25 @@ static int pj_gridinfo_init_ntv2( projCtx ctx, PAFile fid, PJ_GRIDINFO *gilist )
             PJ_GRIDINFO *gp = gridinfo_parent(gilist,
                                                  (const char*)header+24,8);
 
-            if( gp == NULL )
+            if( gp == nullptr )
             {
                 pj_log( ctx, PJ_LOG_ERROR,
                         "pj_gridinfo_init_ntv2(): "
                         "failed to find parent %8.8s for %s.",
                         (const char *) header+24, gi->ct->id );
 
-                for( lnk = gilist; lnk->next != NULL; lnk = lnk->next ) {}
+                for( lnk = gilist; lnk->next != nullptr; lnk = lnk->next ) {}
                 lnk->next = gi;
             }
             else
             {
-                if( gp->child == NULL )
+                if( gp->child == nullptr )
                 {
                     gp->child = gi;
                 }
                 else
                 {
-                    for( lnk = gp->child; lnk->next != NULL; lnk = lnk->next ) {}
+                    for( lnk = gp->child; lnk->next != nullptr; lnk = lnk->next ) {}
                     lnk->next = gi;
                 }
             }
@@ -728,7 +728,7 @@ static int pj_gridinfo_init_ntv1( projCtx ctx, PAFile fid, PJ_GRIDINFO *gi )
     ct->ll.phi *= DEG_TO_RAD;
     ct->del.lam *= DEG_TO_RAD;
     ct->del.phi *= DEG_TO_RAD;
-    ct->cvs = NULL;
+    ct->cvs = nullptr;
 
     gi->ct = ct;
     gi->grid_offset = (long) sizeof(header);
@@ -830,7 +830,7 @@ static int pj_gridinfo_init_gtx( projCtx ctx, PAFile fid, PJ_GRIDINFO *gi )
     ct->ll.phi *= DEG_TO_RAD;
     ct->del.lam *= DEG_TO_RAD;
     ct->del.phi *= DEG_TO_RAD;
-    ct->cvs = NULL;
+    ct->cvs = nullptr;
 
     gi->ct = ct;
     gi->grid_offset = 40;
@@ -867,20 +867,20 @@ PJ_GRIDINFO *pj_gridinfo_init( projCtx ctx, const char *gridname )
     gilist = (PJ_GRIDINFO *) pj_calloc(1, sizeof(PJ_GRIDINFO));
     if (!gilist) {
         pj_ctx_set_errno(ctx, ENOMEM);
-        return NULL;
+        return nullptr;
     }
 
     gilist->gridname = pj_strdup( gridname );
     if (!gilist->gridname) {
         pj_dalloc(gilist);
         pj_ctx_set_errno(ctx, ENOMEM);
-        return NULL;
+        return nullptr;
     }
-    gilist->filename = NULL;
+    gilist->filename = nullptr;
     gilist->format = "missing";
     gilist->grid_offset = 0;
-    gilist->ct = NULL;
-    gilist->next = NULL;
+    gilist->ct = nullptr;
+    gilist->next = nullptr;
 
 /* -------------------------------------------------------------------- */
 /*      Open the file using the usual search rules.                     */
@@ -896,7 +896,7 @@ PJ_GRIDINFO *pj_gridinfo_init( projCtx ctx, const char *gridname )
         pj_dalloc(gilist->gridname);
         pj_dalloc(gilist);
         pj_ctx_set_errno(ctx, ENOMEM);
-        return NULL;
+        return nullptr;
     }
 
 /* -------------------------------------------------------------------- */
@@ -946,7 +946,7 @@ PJ_GRIDINFO *pj_gridinfo_init( projCtx ctx, const char *gridname )
         gilist->format = "ctable2";
         gilist->ct = ct;
 
-        if (ct == NULL)
+        if (ct == nullptr)
         {
             pj_log( ctx, PJ_LOG_DEBUG_MAJOR,
                     "CTABLE V2 ct is NULL.");
@@ -966,7 +966,7 @@ PJ_GRIDINFO *pj_gridinfo_init( projCtx ctx, const char *gridname )
     else
     {
         struct CTABLE *ct = nad_ctable_init( ctx, fp );
-        if (ct == NULL)
+        if (ct == nullptr)
         {
             pj_log( ctx, PJ_LOG_DEBUG_MAJOR,
                     "CTABLE ct is NULL.");
diff --git a/src/pj_gridlist.c b/src/gridlist.cpp
index 332de8dd..169abcb9 100644
--- a/src/pj_gridlist.c
+++ b/src/gridlist.cpp
@@ -34,7 +34,7 @@
 
 #include "projects.h"
 
-static PJ_GRIDINFO *grid_list = NULL;
+static PJ_GRIDINFO *grid_list = nullptr;
 #define PJ_MAX_PATH_LENGTH 1024
 
 /************************************************************************/
@@ -46,11 +46,11 @@ static PJ_GRIDINFO *grid_list = NULL;
 void pj_deallocate_grids()
 
 {
-    while( grid_list != NULL )
+    while( grid_list != nullptr )
     {
         PJ_GRIDINFO *item = grid_list;
         grid_list = grid_list->next;
-        item->next = NULL;
+        item->next = nullptr;
 
         pj_gridinfo_free( pj_get_default_ctx(), item );
     }
@@ -71,21 +71,21 @@ static int pj_gridlist_merge_gridfile( projCtx ctx,
 
 {
     int got_match=0;
-    PJ_GRIDINFO *this_grid, *tail = NULL;
+    PJ_GRIDINFO *this_grid, *tail = nullptr;
 
 /* -------------------------------------------------------------------- */
 /*      Try to find in the existing list of loaded grids.  Add all      */
 /*      matching grids as with NTv2 we can get many grids from one      */
 /*      file (one shared gridname).                                     */
 /* -------------------------------------------------------------------- */
-    for( this_grid = grid_list; this_grid != NULL; this_grid = this_grid->next)
+    for( this_grid = grid_list; this_grid != nullptr; this_grid = this_grid->next)
     {
         if( strcmp(this_grid->gridname,gridname) == 0 )
         {
             got_match = 1;
 
             /* don't add to the list if it is invalid. */
-            if( this_grid->ct == NULL )
+            if( this_grid->ct == nullptr )
                 return 0;
 
             /* do we need to grow the list? */
@@ -99,7 +99,7 @@ static int pj_gridlist_merge_gridfile( projCtx ctx,
                     pj_ctx_set_errno( ctx, ENOMEM );
                     return 0;
                 }
-                if( *p_gridlist != NULL )
+                if( *p_gridlist != nullptr )
                 {
                     memcpy( new_list, *p_gridlist,
                             sizeof(void *) * (*p_gridmax) );
@@ -112,7 +112,7 @@ static int pj_gridlist_merge_gridfile( projCtx ctx,
 
             /* add to the list */
             (*p_gridlist)[(*p_gridcount)++] = this_grid;
-            (*p_gridlist)[*p_gridcount] = NULL;
+            (*p_gridlist)[*p_gridcount] = nullptr;
         }
 
         tail = this_grid;
@@ -126,12 +126,12 @@ static int pj_gridlist_merge_gridfile( projCtx ctx,
 /* -------------------------------------------------------------------- */
     this_grid = pj_gridinfo_init( ctx, gridname );
 
-    if( this_grid == NULL )
+    if( this_grid == nullptr )
     {
         return 0;
     }
     
-    if( tail != NULL )
+    if( tail != nullptr )
         tail->next = this_grid;
     else
         grid_list = this_grid;
@@ -158,7 +158,7 @@ PJ_GRIDINFO **pj_gridlist_from_nadgrids( projCtx ctx, const char *nadgrids,
 
 {
     const char *s;
-    PJ_GRIDINFO **gridlist = NULL;
+    PJ_GRIDINFO **gridlist = nullptr;
     int grid_max = 0;
 
     pj_errno = 0;
@@ -190,7 +190,7 @@ PJ_GRIDINFO **pj_gridlist_from_nadgrids( projCtx ctx, const char *nadgrids,
             pj_dalloc( gridlist );
             pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
             pj_release_lock();
-            return NULL;
+            return nullptr;
         }
         
         strncpy( name, s, end_char );
@@ -207,7 +207,7 @@ PJ_GRIDINFO **pj_gridlist_from_nadgrids( projCtx ctx, const char *nadgrids,
             pj_dalloc( gridlist );
             pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
             pj_release_lock();
-            return NULL;
+            return nullptr;
         }
         else
             pj_errno = 0;
diff --git a/src/pj_init.c b/src/init.cpp
index 36a3276f..5710031c 100644
--- a/src/pj_init.c
+++ b/src/init.cpp
@@ -49,7 +49,7 @@ static paralist *string_to_paralist (PJ_CONTEXT *ctx, char *definition) {
     Convert a string (presumably originating from get_init_string) to a paralist.
 ***************************************************************************************/
     char *c = definition;
-    paralist *first = 0, *next = 0;
+    paralist *first = nullptr, *next = nullptr;
 
     while (*c) {
         /* Find start of next substring */
@@ -57,23 +57,25 @@ static paralist *string_to_paralist (PJ_CONTEXT *ctx, char *definition) {
             c++;
 
         /* Keep a handle to the start of the list, so we have something to return */
-        if (0==first)
+        if (nullptr==first)
             first = next = pj_mkparam_ws (c);
         else
             next = next->next = pj_mkparam_ws (c);
-        if (0==next)
-            return pj_dealloc_params (ctx, first, ENOMEM);
+        if (nullptr==next) {
+            pj_dealloc_params (ctx, first, ENOMEM);
+            return nullptr;
+        }
 
         /* And skip to the end of the substring */
         while ((!isspace(*c)) && 0!=*c)
             c++;
     }
 
-    if( next == 0 )
-        return 0;
+    if( next == nullptr )
+        return nullptr;
 
     /* Terminate list and return */
-    next->next = 0;
+    next->next = nullptr;
     return first;
 }
 
@@ -89,42 +91,42 @@ static char *get_init_string (PJ_CONTEXT *ctx, const char *name) {
     size_t current_buffer_size = 5 * (MAX_LINE_LENGTH + 1);
     char *fname, *section;
     const char *key;
-    char *buffer = 0;
-    char *line = 0;
+    char *buffer = nullptr;
+    char *line = nullptr;
     PAFile fid;
     size_t n;
 
 
-    line = pj_malloc (MAX_LINE_LENGTH + 1);
-    if (0==line)
-        return 0;
+    line = static_cast<char*>(pj_malloc (MAX_LINE_LENGTH + 1));
+    if (nullptr==line)
+        return nullptr;
 
-    fname = pj_malloc (MAX_PATH_FILENAME+ID_TAG_MAX+3);
-    if (0==fname) {
+    fname = static_cast<char*>(pj_malloc (MAX_PATH_FILENAME+ID_TAG_MAX+3));
+    if (nullptr==fname) {
         pj_dealloc (line);
-        return 0;
+        return nullptr;
     }
 
     /* Support "init=file:section", "+init=file:section", and "file:section" format */
     key = strstr (name, "init=");
-    if (0==key)
+    if (nullptr==key)
         key = name;
     else
         key += 5;
     if (MAX_PATH_FILENAME + ID_TAG_MAX + 2 < strlen (key)) {
         pj_dealloc (fname);
         pj_dealloc (line);
-        return 0;
+        return nullptr;
     }
     memmove (fname, key, strlen (key) + 1);
 
     /* Locate the name of the section we search for */
     section = strrchr(fname, ':');
-    if (0==section) {
+    if (nullptr==section) {
         proj_context_errno_set (ctx, PJD_ERR_NO_COLON_IN_INIT_STRING);
         pj_dealloc (fname);
         pj_dealloc (line);
-        return 0;
+        return nullptr;
     }
     *section = 0;
     section++;
@@ -134,24 +136,24 @@ static char *get_init_string (PJ_CONTEXT *ctx, const char *name) {
             section, fname);
 
     fid = pj_open_lib (ctx, fname, "rt");
-    if (0==fid) {
+    if (nullptr==fid) {
         pj_dealloc (fname);
         pj_dealloc (line);
         proj_context_errno_set (ctx, PJD_ERR_NO_OPTION_IN_INIT_FILE);
-        return 0;
+        return nullptr;
     }
 
     /* Search for section in init file */
     for (;;) {
 
         /* End of file? */
-        if (0==pj_ctx_fgets (ctx, line, MAX_LINE_LENGTH, fid)) {
+        if (nullptr==pj_ctx_fgets (ctx, line, MAX_LINE_LENGTH, fid)) {
             pj_dealloc (buffer);
             pj_dealloc (fname);
             pj_dealloc (line);
             pj_ctx_fclose (ctx, fid);
             proj_context_errno_set (ctx, PJD_ERR_NO_OPTION_IN_INIT_FILE);
-            return 0;
+            return nullptr;
         }
 
         /* At start of right section? */
@@ -167,12 +169,12 @@ static char *get_init_string (PJ_CONTEXT *ctx, const char *name) {
     }
 
     /* We're at the first line of the right section - copy line to buffer */
-    buffer = pj_malloc (current_buffer_size);
-    if (0==buffer) {
+    buffer = static_cast<char*>(pj_malloc (current_buffer_size));
+    if (nullptr==buffer) {
         pj_dealloc (fname);
         pj_dealloc (line);
         pj_ctx_fclose (ctx, fid);
-        return 0;
+        return nullptr;
     }
 
     /* Skip the "<section>" indicator, and copy the rest of the line over */
@@ -191,7 +193,7 @@ static char *get_init_string (PJ_CONTEXT *ctx, const char *name) {
         }
 
         /* End of file? - done! */
-        if (0==pj_ctx_fgets (ctx, line, MAX_LINE_LENGTH, fid))
+        if (nullptr==pj_ctx_fgets (ctx, line, MAX_LINE_LENGTH, fid))
             break;
 
         /* Otherwise, handle the line. It MAY be the start of the next section, */
@@ -200,10 +202,10 @@ static char *get_init_string (PJ_CONTEXT *ctx, const char *name) {
         pj_chomp (line);   /* Remove '#' style comments */
         next_length = strlen (line) + buffer_length + 2;
         if (next_length > current_buffer_size) {
-            char *b = pj_malloc (2 * current_buffer_size);
-            if (0==b) {
+            char *b = static_cast<char*>(pj_malloc (2 * current_buffer_size));
+            if (nullptr==b) {
                 pj_dealloc (buffer);
-                buffer = 0;
+                buffer = nullptr;
                 break;
             }
             strcpy (b, buffer);
@@ -218,8 +220,8 @@ static char *get_init_string (PJ_CONTEXT *ctx, const char *name) {
     pj_ctx_fclose (ctx, fid);
     pj_dealloc (fname);
     pj_dealloc (line);
-    if (0==buffer)
-        return 0;
+    if (nullptr==buffer)
+        return nullptr;
     pj_shrink (buffer);
     pj_log (ctx, PJ_LOG_TRACE, "key=%s, value: [%s]", key, buffer);
     return buffer;
@@ -233,12 +235,12 @@ static paralist *get_init(PJ_CONTEXT *ctx, const char *key, int allow_init_epsg)
 Expand key from buffer or (if not in buffer) from init file
 *************************************************************************/
     const char *xkey;
-    char *definition = 0;
-    paralist *init_items = 0;
+    char *definition = nullptr;
+    paralist *init_items = nullptr;
 
     /* support "init=file:section", "+init=file:section", and "file:section" format */
     xkey = strstr (key, "init=");
-    if (0==xkey)
+    if (nullptr==xkey)
         xkey = key;
     else
         xkey += 5;
@@ -268,7 +270,7 @@ Expand key from buffer or (if not in buffer) from init file
         }
 
         if( !exists ) {
-            const char* const optionsProj4Mode[] = { "USE_PROJ4_INIT_RULES=YES", NULL };
+            const char* const optionsProj4Mode[] = { "USE_PROJ4_INIT_RULES=YES", nullptr };
             char szInitStr[7 + 64];
             PJ_OBJ* src;
             const char* proj_string;
@@ -277,23 +279,23 @@ Expand key from buffer or (if not in buffer) from init file
 
             if( !allow_init_epsg ) {
                 pj_log (ctx, PJ_LOG_TRACE, "%s expansion disallowed", xkey);
-                return 0;
+                return nullptr;
             }
             if( strlen(xkey) > 64 ) {
-                return 0;
+                return nullptr;
             }
             strcpy(szInitStr, "+init=");
             strcat(szInitStr, xkey);
 
             src = proj_obj_create_from_user_input(ctx, szInitStr, optionsProj4Mode);
             if( !src ) {
-                return 0;
+                return nullptr;
             }
 
-            proj_string = proj_obj_as_proj_string(ctx, src, PJ_PROJ_4, NULL);
+            proj_string = proj_obj_as_proj_string(ctx, src, PJ_PROJ_4, nullptr);
             if( !proj_string ) {
                 proj_obj_destroy(src);
-                return 0;
+                return nullptr;
             }
             definition = (char*)calloc(1, strlen(proj_string)+1);
             if( definition ) {
@@ -311,8 +313,8 @@ Expand key from buffer or (if not in buffer) from init file
         definition = get_init_string (ctx, xkey);
     }
 
-    if (0==definition)
-        return 0;
+    if (nullptr==definition)
+        return nullptr;
     init_items = string_to_paralist (ctx, definition);
     if (init_items)
         pj_log (ctx, PJ_LOG_TRACE, "get_init: got [%s], paralist[0,1]: [%s,%s]",
@@ -320,8 +322,8 @@ Expand key from buffer or (if not in buffer) from init file
                 init_items->param,
                 init_items->next ? init_items->next->param : "(empty)");
     pj_dealloc (definition);
-    if (0==init_items)
-        return 0;
+    if (nullptr==init_items)
+        return nullptr;
 
     /* We found it in file - now insert into the cache, before returning */
     pj_insert_initcache (xkey, init_items);
@@ -331,23 +333,23 @@ Expand key from buffer or (if not in buffer) from init file
 
 
 static paralist *append_defaults_to_paralist (PJ_CONTEXT *ctx, paralist *start, const char *key, int allow_init_epsg) {
-    paralist *defaults, *last = 0;
+    paralist *defaults, *last = nullptr;
     char keystring[ID_TAG_MAX + 20];
     paralist *next, *proj;
     int err;
 
-    if (0==start)
-        return 0;
+    if (nullptr==start)
+        return nullptr;
 
     if (strlen(key) > ID_TAG_MAX)
-        return 0;
+        return nullptr;
 
     /* Set defaults, unless inhibited (either explicitly through a "no_defs" token */
     /* or implicitly, because we are initializing a pipeline) */
     if (pj_param_exists (start, "no_defs"))
         return start;
     proj = pj_param_exists (start, "proj");
-    if (0==proj)
+    if (nullptr==proj)
         return start;
     if (strlen (proj->param) < 6)
         return start;
@@ -392,7 +394,7 @@ static paralist *append_defaults_to_paralist (PJ_CONTEXT *ctx, paralist *start,
         /* If we're here, it's OK to append the current default item */
         last = last->next = pj_mkparam(next->param);
     }
-    last->next = 0;
+    last->next = nullptr;
 
     pj_dealloc_params (ctx, defaults, 0);
     return last;
@@ -423,14 +425,14 @@ Note that 'init=foo:bar' stays in the list. It is ignored after expansion.
     paralist *expn;
 
     /* Nowhere to start? */
-    if (0==init)
-        return 0;
+    if (nullptr==init)
+        return nullptr;
 
     expn = get_init(ctx, init->param, allow_init_epsg);
 
     /* Nothing in expansion? */
-    if (0==expn)
-        return 0;
+    if (nullptr==expn)
+        return nullptr;
 
     /* Locate  the end of the list */
     for (last = init;  last && last->next;  last = last->next);
@@ -467,12 +469,12 @@ pj_init_plus_ctx( projCtx ctx, const char *definition )
     char	*argv[MAX_ARG];
     char	*defn_copy;
     int		argc = 0, i, blank_count = 0;
-    PJ	    *result = NULL;
+    PJ	    *result = nullptr;
 
     /* make a copy that we can manipulate */
     defn_copy = (char *) pj_malloc( strlen(definition)+1 );
     if (!defn_copy)
-        return NULL;
+        return nullptr;
     strcpy( defn_copy, definition );
 
     /* split into arguments based on '+' and trim white space */
@@ -495,7 +497,7 @@ pj_init_plus_ctx( projCtx ctx, const char *definition )
                 {
                     pj_dalloc( defn_copy );
                     pj_ctx_set_errno( ctx, PJD_ERR_UNPARSEABLE_CS_DEF );
-                    return 0;
+                    return nullptr;
                 }
 
                 argv[argc++] = defn_copy + i + 1;
@@ -550,8 +552,8 @@ static PJ_CONSTRUCTOR locate_constructor (const char *name) {
     const PJ_OPERATIONS *operations;
     operations = proj_list_operations();
     for (i = 0; (s = operations[i].id) && strcmp(name, s) ; ++i) ;
-    if (0==s)
-        return 0;
+    if (nullptr==s)
+        return nullptr;
     return (PJ_CONSTRUCTOR) operations[i].proj;
 }
 
@@ -572,20 +574,20 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
     paralist *curr, *init, *start;
     int i;
     int err;
-    PJ *PIN = 0;
+    PJ *PIN = nullptr;
     int n_pipelines = 0;
     int n_inits = 0;
     const PJ_UNITS *units;
     const PJ_PRIME_MERIDIANS *prime_meridians;
 
-    if (0==ctx)
+    if (nullptr==ctx)
         ctx = pj_get_default_ctx ();
 
     ctx->last_errno = 0;
 
     if (argc <= 0) {
         pj_ctx_set_errno (ctx, PJD_ERR_NO_ARGS);
-        return 0;
+        return nullptr;
     }
 
     /* count occurrences of pipelines and inits */
@@ -599,25 +601,29 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
     /* can't have nested pipelines directly */
     if (n_pipelines > 1) {
         pj_ctx_set_errno (ctx, PJD_ERR_MALFORMED_PIPELINE);
-        return 0;
+        return nullptr;
     }
 
     /* don't allow more than one +init in non-pipeline operations */
     if (n_pipelines == 0 && n_inits > 1) {
         pj_ctx_set_errno (ctx, PJD_ERR_TOO_MANY_INITS);
-        return 0;
+        return nullptr;
     }
 
 
     /* put arguments into internal linked list */
     start = curr = pj_mkparam(argv[0]);
-    if (!curr)
-        return pj_dealloc_params (ctx, start, ENOMEM);
+    if (!curr) {
+        pj_dealloc_params (ctx, start, ENOMEM);
+        return nullptr;
+    }
 
     for (i = 1; i < argc; ++i) {
         curr->next = pj_mkparam(argv[i]);
-        if (!curr->next)
-            return pj_dealloc_params (ctx, start, ENOMEM);
+        if (!curr->next) {
+            pj_dealloc_params (ctx, start, ENOMEM);
+            return nullptr;
+        }
         curr = curr->next;
     }
 
@@ -629,24 +635,34 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
     init = pj_param_exists (start, "init");
     if (init && n_pipelines == 0) {
         init = pj_expand_init_internal (ctx, init, allow_init_epsg);
-        if (!init)
-            return pj_dealloc_params (ctx, start, PJD_ERR_NO_ARGS);
+        if (!init) {
+            pj_dealloc_params (ctx, start, PJD_ERR_NO_ARGS);
+            return nullptr;
+        }
+    }
+    if (ctx->last_errno) {
+        pj_dealloc_params (ctx, start, ctx->last_errno);
+        return nullptr;
     }
-    if (ctx->last_errno)
-        return pj_dealloc_params (ctx, start, ctx->last_errno);
 
     /* Find projection selection */
     curr = pj_param_exists (start, "proj");
-    if (0==curr)
-        return pj_dealloc_params (ctx, start, PJD_ERR_PROJ_NOT_NAMED);
+    if (nullptr==curr) {
+        pj_dealloc_params (ctx, start, PJD_ERR_PROJ_NOT_NAMED);
+        return nullptr;
+    }
     name =  curr->param;
-    if (strlen (name) < 6)
-        return pj_dealloc_params (ctx, start, PJD_ERR_PROJ_NOT_NAMED);
+    if (strlen (name) < 6) {
+        pj_dealloc_params (ctx, start, PJD_ERR_PROJ_NOT_NAMED);
+        return nullptr;
+    }
     name += 5;
 
     proj = locate_constructor (name);
-    if (0==proj)
-        return pj_dealloc_params (ctx, start, PJD_ERR_UNKNOWN_PROJECTION_ID);
+    if (nullptr==proj) {
+        pj_dealloc_params (ctx, start, PJD_ERR_UNKNOWN_PROJECTION_ID);
+        return nullptr;
+    }
 
 
     /* Append general and projection specific defaults to the definition list */
@@ -655,9 +671,11 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
 
 
     /* Allocate projection structure */
-    PIN = proj(0);
-    if (0==PIN)
-        return pj_dealloc_params (ctx, start, ENOMEM);
+    PIN = proj(nullptr);
+    if (nullptr==PIN) {
+        pj_dealloc_params (ctx, start, ENOMEM);
+        return nullptr;
+    }
 
 
     PIN->ctx = ctx;
@@ -668,10 +686,10 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
     PIN->long_wrap_center = 0.0;
     strcpy( PIN->axis, "enu" );
 
-    PIN->gridlist = NULL;
+    PIN->gridlist = nullptr;
     PIN->gridlist_count = 0;
 
-    PIN->vgridlist_geoid = NULL;
+    PIN->vgridlist_geoid = nullptr;
     PIN->vgridlist_geoid_count = 0;
 
     /* Set datum parameters. Similarly to +init parameters we want to expand    */
@@ -737,16 +755,16 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
     }
 
     /* Axis orientation */
-    if( (pj_param(ctx, start,"saxis").s) != NULL )
+    if( (pj_param(ctx, start,"saxis").s) != nullptr )
     {
         const char *axis_legal = "ewnsud";
         const char *axis_arg = pj_param(ctx, start,"saxis").s;
         if( strlen(axis_arg) != 3 )
             return pj_default_destructor (PIN, PJD_ERR_AXIS);
 
-        if( strchr( axis_legal, axis_arg[0] ) == NULL
-            || strchr( axis_legal, axis_arg[1] ) == NULL
-            || strchr( axis_legal, axis_arg[2] ) == NULL)
+        if( strchr( axis_legal, axis_arg[0] ) == nullptr
+            || strchr( axis_legal, axis_arg[1] ) == nullptr
+            || strchr( axis_legal, axis_arg[2] ) == nullptr)
             return pj_default_destructor (PIN, PJD_ERR_AXIS);
 
         /* TODO: it would be nice to validate we don't have on axis repeated */
@@ -777,8 +795,8 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
 
     /* Set units */
     units = proj_list_units();
-    s = 0;
-    if ((name = pj_param(ctx, start, "sunits").s) != NULL) {
+    s = nullptr;
+    if ((name = pj_param(ctx, start, "sunits").s) != nullptr) {
         for (i = 0; (s = units[i].id) && strcmp(name, s) ; ++i) ;
         if (!s)
             return pj_default_destructor (PIN, PJD_ERR_UNKNOWN_UNIT_ID);
@@ -794,7 +812,7 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
             s += 2;
         }
 
-        factor = pj_strtod(s, 0);
+        factor = pj_strtod(s, nullptr);
         if ((factor <= 0.0) || (1/factor==0))
             return pj_default_destructor (PIN, PJD_ERR_UNIT_FACTOR_LESS_THAN_0);
 
@@ -805,17 +823,17 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
         PIN->to_meter = PIN->fr_meter = 1.;
 
     /* Set vertical units */
-    s = 0;
-    if ((name = pj_param(ctx, start, "svunits").s) != NULL) {
+    s = nullptr;
+    if ((name = pj_param(ctx, start, "svunits").s) != nullptr) {
         for (i = 0; (s = units[i].id) && strcmp(name, s) ; ++i) ;
         if (!s)
             return pj_default_destructor (PIN, PJD_ERR_UNKNOWN_UNIT_ID);
         s = units[i].to_meter;
     }
     if (s || (s = pj_param(ctx, start, "svto_meter").s)) {
-        PIN->vto_meter = pj_strtod(s, 0);
+        PIN->vto_meter = pj_strtod(s, nullptr);
         if (*s == '/') /* ratio number */
-            PIN->vto_meter /= pj_strtod(++s, 0);
+            PIN->vto_meter /= pj_strtod(++s, nullptr);
         if (PIN->vto_meter <= 0.0)
             return pj_default_destructor (PIN, PJD_ERR_UNIT_FACTOR_LESS_THAN_0);
         PIN->vfr_meter = 1. / PIN->vto_meter;
@@ -826,12 +844,12 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
 
     /* Prime meridian */
     prime_meridians = proj_list_prime_meridians();
-    s = 0;
-    if ((name = pj_param(ctx, start, "spm").s) != NULL) {
-        const char *value = NULL;
-        char *next_str = NULL;
+    s = nullptr;
+    if ((name = pj_param(ctx, start, "spm").s) != nullptr) {
+        const char *value = nullptr;
+        char *next_str = nullptr;
 
-        for (i = 0; prime_meridians[i].id != NULL; ++i )
+        for (i = 0; prime_meridians[i].id != nullptr; ++i )
         {
             if( strcmp(name,prime_meridians[i].id) == 0 )
             {
@@ -840,21 +858,21 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
             }
         }
 
-        if( value == NULL
+        if( value == nullptr
             && (dmstor_ctx(ctx,name,&next_str) != 0.0  || *name == '0')
             && *next_str == '\0' )
             value = name;
 
         if (!value)
             return pj_default_destructor (PIN, PJD_ERR_UNKNOWN_PRIME_MERIDIAN);
-        PIN->from_greenwich = dmstor_ctx(ctx,value,NULL);
+        PIN->from_greenwich = dmstor_ctx(ctx,value,nullptr);
     }
     else
         PIN->from_greenwich = 0.0;
 
     /* Private object for the geodesic functions */
-    PIN->geod = pj_calloc (1, sizeof (struct geod_geodesic));
-    if (0==PIN->geod)
+    PIN->geod = static_cast<struct geod_geodesic*>(pj_calloc (1, sizeof (struct geod_geodesic)));
+    if (nullptr==PIN->geod)
         return pj_default_destructor (PIN, ENOMEM);
     geod_init(PIN->geod, PIN->a,  (1 - sqrt (1 - PIN->es)));
 
@@ -863,7 +881,7 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
     PIN = proj(PIN);
     if (proj_errno (PIN)) {
         pj_free(PIN);
-        return 0;
+        return nullptr;
     }
     proj_errno_restore (PIN, err);
     return PIN;
diff --git a/src/pj_initcache.c b/src/initcache.cpp
index 3c347e4b..052a016c 100644
--- a/src/pj_initcache.c
+++ b/src/initcache.cpp
@@ -31,8 +31,8 @@
 
 static int cache_count = 0;
 static int cache_alloc = 0;
-static char **cache_key = NULL;
-static paralist **cache_paralist = NULL;
+static char **cache_key = nullptr;
+static paralist **cache_paralist = nullptr;
 
 /************************************************************************/
 /*                            pj_clone_paralist()                       */
@@ -42,18 +42,18 @@ static paralist **cache_paralist = NULL;
 
 paralist *pj_clone_paralist( const paralist *list)
 {
-  paralist *list_copy = NULL, *next_copy = NULL;
+  paralist *list_copy = nullptr, *next_copy = nullptr;
 
-  for( ; list != NULL; list = list->next )
+  for( ; list != nullptr; list = list->next )
     {
       paralist *newitem = (paralist *)
 	pj_malloc(sizeof(paralist) + strlen(list->param));
 
       newitem->used = 0;
-      newitem->next = 0;
+      newitem->next = nullptr;
       strcpy( newitem->param, list->param );
 
-      if( list_copy == NULL )
+      if( list_copy == nullptr )
 	list_copy = newitem;
       else
 	next_copy->next = newitem;
@@ -85,7 +85,7 @@ void pj_clear_initcache()
             pj_dalloc( cache_key[i] );
 
             /* free parameter list elements */
-            for (; t != NULL; t = n) {
+            for (; t != nullptr; t = n) {
                 n = t->next;
                 pj_dalloc(t);
             }
@@ -95,8 +95,8 @@ void pj_clear_initcache()
         pj_dalloc( cache_paralist );
         cache_count = 0;
         cache_alloc= 0;
-        cache_key = NULL;
-        cache_paralist = NULL;
+        cache_key = nullptr;
+        cache_paralist = nullptr;
 
         pj_release_lock();
     }
@@ -112,11 +112,11 @@ paralist *pj_search_initcache( const char *filekey )
 
 {
     int i;
-    paralist *result = NULL;
+    paralist *result = nullptr;
 
     pj_acquire_lock();
 
-    for( i = 0; result == NULL && i < cache_count; i++)
+    for( i = 0; result == nullptr && i < cache_count; i++)
     {
         if( strcmp(filekey,cache_key[i]) == 0 )
 	{
diff --git a/src/internal.cpp b/src/internal.cpp
index c43605d1..3f3d191e 100644
--- a/src/internal.cpp
+++ b/src/internal.cpp
@@ -1,11 +1,14 @@
 /******************************************************************************
+ * Project:  PROJ.4
+ * Purpose:  This is primarily material originating from pj_obs_api.c
+ *           (now proj_4D_api.c), that does not fit into the API
+ *           category. Hence this pile of tubings and fittings for
+ *           PROJ.4 internal plumbing.
  *
- * Project:  PROJ
- * Purpose:  ISO19111:2018 implementation
- * Author:   Even Rouault <even dot rouault at spatialys dot com>
+ * Author:   Thomas Knudsen,  thokn@sdfe.dk,  2017-07-05
  *
  ******************************************************************************
- * Copyright (c) 2018, Even Rouault <even dot rouault at spatialys dot com>
+ * Copyright (c) 2016, 2017, 2018, Thomas Knudsen/SDFE
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -24,351 +27,419 @@
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
- ****************************************************************************/
+ *****************************************************************************/
+
+#include <ctype.h>
+#include <errno.h>
+#include <math.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
 
-#ifndef FROM_PROJ_CPP
-#define FROM_PROJ_CPP
-#endif
+#include "geodesic.h"
+#include "proj_internal.h"
+#include "projects.h"
 
-#include "proj/internal/internal.hpp"
 
-#include <cstdint>
-#include <cstring>
-#ifdef _MSC_VER
-#include <string.h>
-#else
-#include <strings.h>
-#endif
-#include <exception>
-#include <iomanip> // std::setprecision
-#include <locale>
-#include <sstream> // std::istringstream and std::ostringstream
-#include <string>
-
-#include "sqlite3.h"
-
-NS_PROJ_START
-
-namespace internal {
-
-// ---------------------------------------------------------------------------
-
-/**
- * Replace all occurrences of before with after.
- */
-std::string replaceAll(const std::string &str, const std::string &before,
-                       const std::string &after) {
-    std::string ret(str);
-    const size_t nBeforeSize = before.size();
-    const size_t nAfterSize = after.size();
-    if (nBeforeSize) {
-        size_t nStartPos = 0;
-        while ((nStartPos = ret.find(before, nStartPos)) != std::string::npos) {
-            ret.replace(nStartPos, nBeforeSize, after);
-            nStartPos += nAfterSize;
-        }
-    }
-    return ret;
+enum pj_io_units pj_left (PJ *P) {
+    enum pj_io_units u = P->inverted? P->right: P->left;
+    if (u==PJ_IO_UNITS_CLASSIC)
+        return PJ_IO_UNITS_PROJECTED;
+    return u;
 }
 
-// ---------------------------------------------------------------------------
-
-inline static bool EQUALN(const char *a, const char *b, size_t size) {
-#ifdef _MSC_VER
-    return _strnicmp(a, b, size) == 0;
-#else
-    return strncasecmp(a, b, size) == 0;
-#endif
+enum pj_io_units pj_right (PJ *P) {
+    enum pj_io_units u = P->inverted? P->left: P->right;
+    if (u==PJ_IO_UNITS_CLASSIC)
+        return PJ_IO_UNITS_PROJECTED;
+    return u;
 }
 
-/**
- * Case-insensitive equality test
- */
-bool ci_equal(const std::string &a, const std::string &b) noexcept {
-    const auto size = a.size();
-    if (size != b.size()) {
-        return false;
-    }
-    return EQUALN(a.c_str(), b.c_str(), size);
+
+/* Work around non-constness of MSVC HUGE_VAL by providing functions rather than constants */
+PJ_COORD proj_coord_error (void) {
+    PJ_COORD c;
+    c.v[0] = c.v[1] = c.v[2] = c.v[3] = HUGE_VAL;
+    return c;
 }
 
-bool ci_equal(const std::string &a, const char *b) noexcept {
-    const auto size = a.size();
-    if (size != strlen(b)) {
-        return false;
+
+
+/**************************************************************************************/
+PJ_COORD pj_approx_2D_trans (PJ *P, PJ_DIRECTION direction, PJ_COORD coo) {
+/***************************************************************************************
+Behave mostly as proj_trans, but attempt to use 2D interfaces only.
+Used in gie.c, to enforce testing 2D code, and by PJ_pipeline.c to implement
+chained calls starting out with a call to its 2D interface.
+***************************************************************************************/
+    if (nullptr==P)
+        return coo;
+    if (P->inverted)
+        direction = static_cast<PJ_DIRECTION>(-direction);
+    switch (direction) {
+        case PJ_FWD:
+            coo.xy = pj_fwd (coo.lp, P);
+            return coo;
+        case PJ_INV:
+            coo.lp = pj_inv (coo.xy, P);
+            return coo;
+        case PJ_IDENT:
+            return coo;
+        default:
+            break;
     }
-    return EQUALN(a.c_str(), b, size);
+    proj_errno_set (P, EINVAL);
+    return proj_coord_error ();
 }
 
-bool ci_equal(const char *a, const char *b) noexcept {
-    const auto size = strlen(a);
-    if (size != strlen(b)) {
-        return false;
+
+/**************************************************************************************/
+PJ_COORD pj_approx_3D_trans (PJ *P, PJ_DIRECTION direction, PJ_COORD coo) {
+/***************************************************************************************
+Companion to pj_approx_2D_trans.
+
+Behave mostly as proj_trans, but attempt to use 3D interfaces only.
+Used in gie.c, to enforce testing 3D code, and by PJ_pipeline.c to implement
+chained calls starting out with a call to its 3D interface.
+***************************************************************************************/
+    if (nullptr==P)
+        return coo;
+    if (P->inverted)
+        direction = static_cast<PJ_DIRECTION>(-direction);
+    switch (direction) {
+        case PJ_FWD:
+            coo.xyz = pj_fwd3d (coo.lpz, P);
+            return coo;
+        case PJ_INV:
+            coo.lpz = pj_inv3d (coo.xyz, P);
+            return coo;
+        case PJ_IDENT:
+            return coo;
+        default:
+            break;
     }
-    return EQUALN(a, b, size);
+    proj_errno_set (P, EINVAL);
+    return proj_coord_error ();
 }
 
-// ---------------------------------------------------------------------------
-
-bool ci_less(const std::string &a, const std::string &b) noexcept {
-#ifdef _MSC_VER
-    return _stricmp(a.c_str(), b.c_str()) < 0;
-#else
-    return strcasecmp(a.c_str(), b.c_str()) < 0;
-#endif
+/**************************************************************************************/
+int pj_has_inverse(PJ *P) {
+/***************************************************************************************
+Check if a a PJ has an inverse.
+***************************************************************************************/
+    return ( (P->inverted && (P->fwd || P->fwd3d || P->fwd4d) ) ||
+             ( P->inv || P->inv3d || P->inv4d) );
 }
 
-// ---------------------------------------------------------------------------
 
-/**
- * Convert to lower case.
- */
+/* Move P to a new context - or to the default context if 0 is specified */
+void proj_context_set (PJ *P, PJ_CONTEXT *ctx) {
+    if (nullptr==ctx)
+        ctx = pj_get_default_ctx ();
+    pj_set_ctx (P, ctx);
+}
 
-std::string tolower(const std::string &str)
 
-{
-    std::string ret(str);
-    for (size_t i = 0; i < ret.size(); i++)
-        ret[i] = static_cast<char>(::tolower(ret[i]));
-    return ret;
+void proj_context_inherit (PJ *parent, PJ *child) {
+    if (nullptr==parent)
+        pj_set_ctx (child, pj_get_default_ctx());
+    else
+        pj_set_ctx (child, pj_get_ctx(parent));
 }
 
-// ---------------------------------------------------------------------------
 
-/**
- * Convert to upper case.
- */
 
-std::string toupper(const std::string &str)
+/*****************************************************************************/
+char *pj_chomp (char *c) {
+/******************************************************************************
+Strip pre- and postfix whitespace. Inline comments (indicated by '#') are
+considered whitespace.
+******************************************************************************/
+    size_t i, n;
+    char *comment;
+    char *start = c;
+
+    if (nullptr==c)
+        return nullptr;
+
+    comment = strchr (c, '#');
+    if (comment)
+        *comment = 0;
+
+    n = strlen (c);
+    if (0==n)
+        return c;
+
+    /* Eliminate postfix whitespace */
+    for (i = n - 1;  (i > 0) && (isspace (c[i]) || ';'==c[i]);  i--)
+        c[i] = 0;
+
+    /* Find start of non-whitespace */
+    while (0 != *start  &&  (';'==*start  ||  isspace (*start)))
+        start++;
+
+    n = strlen (start);
+    if (0==n) {
+        c[0] = 0;
+        return c;
+    }
 
-{
-    std::string ret(str);
-    for (size_t i = 0; i < ret.size(); i++)
-        ret[i] = static_cast<char>(::toupper(ret[i]));
-    return ret;
+    memmove (c, start, n + 1);
+    return c;
 }
 
-// ---------------------------------------------------------------------------
 
-/** Strip leading and trailing double quote characters */
-std::string stripQuotes(const std::string &str) {
-    if (str.size() >= 2 && str[0] == '"' && str.back() == '"') {
-        return str.substr(1, str.size() - 2);
-    }
-    return str;
-}
 
-// ---------------------------------------------------------------------------
-
-size_t ci_find(const std::string &str, const char *needle) noexcept {
-    const size_t needleSize = strlen(needle);
-    for (size_t i = 0; i + needleSize <= str.size(); i++) {
-        if (EQUALN(str.c_str() + i, needle, needleSize)) {
-            return i;
+/*****************************************************************************/
+char *pj_shrink (char *c) {
+/******************************************************************************
+Collapse repeated whitespace. Remove '+' and ';'. Make ',' and '=' greedy,
+consuming their surrounding whitespace.
+******************************************************************************/
+    size_t i, j, n;
+
+    /* Flag showing that a whitespace (ws) has been written after last non-ws */
+    size_t ws;
+
+    if (nullptr==c)
+       return nullptr;
+
+    pj_chomp (c);
+    n = strlen (c);
+
+    /* First collapse repeated whitespace (including +/;) */
+    i = 0;
+    ws = 0;
+    for (j = 0;  j < n;  j++) {
+
+        /* Eliminate prefix '+', only if preceded by whitespace */
+        /* (i.e. keep it in 1.23e+08) */
+        if ((i > 0) && ('+'==c[j]) && ws)
+            c[j] = ' ';
+        if ((i==0) && ('+'==c[j]))
+            c[j] = ' ';
+
+        if (isspace (c[j]) || ';'==c[j]) {
+            if (0==ws && (i > 0))
+                c[i++] = ' ';
+            ws = 1;
+            continue;
         }
-    }
-    return std::string::npos;
-}
-
-// ---------------------------------------------------------------------------
-
-size_t ci_find(const std::string &str, const std::string &needle,
-               size_t startPos) noexcept {
-    const size_t needleSize = needle.size();
-    for (size_t i = startPos; i + needleSize <= str.size(); i++) {
-        if (EQUALN(str.c_str() + i, needle.c_str(), needleSize)) {
-            return i;
+        else {
+            ws = 0;
+            c[i++] = c[j];
         }
     }
-    return std::string::npos;
-}
-
-// ---------------------------------------------------------------------------
+    c[i] = 0;
+    n = strlen(c);
+
+    /* Then make ',' and '=' greedy */
+    i = 0;
+    for (j = 0;  j < n;  j++) {
+        if (i==0) {
+            c[i++] = c[j];
+            continue;
+        }
 
-/*
-bool starts_with(const std::string &str, const std::string &prefix) noexcept {
-    if (str.size() < prefix.size()) {
-        return false;
-    }
-    return std::memcmp(str.c_str(), prefix.c_str(), prefix.size()) == 0;
-}
-*/
+        /* Skip space before '='/',' */
+        if ('='==c[j] || ','==c[j]) {
+            if (c[i - 1]==' ')
+               c[i - 1] = c[j];
+            else
+                c[i++] = c[j];
+            continue;
+        }
 
-// ---------------------------------------------------------------------------
+        if (' '==c[j] && ('='==c[i - 1] || ','==c[i - 1]) )
+            continue;
 
-/*
-bool starts_with(const std::string &str, const char *prefix) noexcept {
-    const size_t prefixSize = std::strlen(prefix);
-    if (str.size() < prefixSize) {
-        return false;
+        c[i++] = c[j];
     }
-    return std::memcmp(str.c_str(), prefix, prefixSize) == 0;
+    c[i] = 0;
+    return c;
 }
-*/
 
-// ---------------------------------------------------------------------------
 
-bool ci_starts_with(const char *str, const char *prefix) noexcept {
-    const auto str_size = strlen(str);
-    const auto prefix_size = strlen(prefix);
-    if (str_size < prefix_size) {
-        return false;
-    }
-    return EQUALN(str, prefix, prefix_size);
-}
 
-// ---------------------------------------------------------------------------
-
-bool ci_starts_with(const std::string &str,
-                    const std::string &prefix) noexcept {
-    if (str.size() < prefix.size()) {
-        return false;
+/*****************************************************************************/
+size_t pj_trim_argc (char *args) {
+/******************************************************************************
+Trim all unnecessary whitespace (and non-essential syntactic tokens) from the
+argument string, args, and count its number of elements.
+******************************************************************************/
+    size_t i, m, n;
+    pj_shrink (args);
+    n = strlen (args);
+    if (n==0)
+        return 0;
+    for (i = m = 0;  i < n;  i++) {
+        if (' '==args[i]) {
+            args[i] = 0;
+            m++;
+        }
     }
-    return EQUALN(str.c_str(), prefix.c_str(), prefix.size());
+    return m + 1;
 }
 
-// ---------------------------------------------------------------------------
 
-bool ends_with(const std::string &str, const std::string &suffix) noexcept {
-    if (str.size() < suffix.size()) {
-        return false;
-    }
-    return std::memcmp(str.c_str() + str.size() - suffix.size(), suffix.c_str(),
-                       suffix.size()) == 0;
-}
 
-// ---------------------------------------------------------------------------
-
-double c_locale_stod(const std::string &s) {
-
-    const auto s_size = s.size();
-    // Fast path
-    if (s_size > 0 && s_size < 15) {
-        std::int64_t acc = 0;
-        std::int64_t div = 1;
-        bool afterDot = false;
-        size_t i = 0;
-        if (s[0] == '-') {
-            ++i;
-            div = -1;
-        } else if (s[0] == '+') {
-            ++i;
-        }
-        for (; i < s_size; ++i) {
-            const auto ch = s[i];
-            if (ch >= '0' && ch <= '9') {
-                acc = acc * 10 + ch - '0';
-                if (afterDot) {
-                    div *= 10;
-                }
-            } else if (ch == '.') {
-                afterDot = true;
-            } else {
-                div = 0;
-            }
-        }
-        if (div) {
-            return static_cast<double>(acc) / div;
+/*****************************************************************************/
+char **pj_trim_argv (size_t argc, char *args) {
+/******************************************************************************
+Create an argv-style array from elements placed in the argument string, args.
+
+args is a trimmed string as returned by pj_trim_argc(), and argc is the number
+of trimmed strings found (i.e. the return value of pj_trim_args()). Hence,
+    int argc    = pj_trim_argc (args);
+    char **argv = pj_trim_argv (argc, args);
+will produce a classic style (argc, argv) pair from a string of whitespace
+separated args. No new memory is allocated for storing the individual args
+(they stay in the args string), but for the pointers to the args a new array
+is allocated and returned.
+
+It is the duty of the caller to free this array.
+******************************************************************************/
+    size_t i, j;
+    char **argv;
+
+    if (nullptr==args)
+        return nullptr;
+    if (0==argc)
+        return nullptr;
+
+
+    /* turn the input string into an array of strings */
+    argv = (char **) calloc (argc, sizeof (char *));
+    if (nullptr==argv)
+        return nullptr;
+    argv[0] = args;
+    j = 1;
+    for (i = 0;  ;  i++) {
+        if (0==args[i]) {
+            argv[j++] = args + (i + 1);
         }
+        if (j==argc)
+            break;
     }
-
-    std::istringstream iss(s);
-    iss.imbue(std::locale::classic());
-    double d;
-    iss >> d;
-    if (!iss.eof() || iss.fail()) {
-        throw std::invalid_argument("non double value");
-    }
-    return d;
+    return argv;
 }
 
-// ---------------------------------------------------------------------------
 
-std::vector<std::string> split(const std::string &str, char separator) {
-    std::vector<std::string> res;
-    size_t lastPos = 0;
-    size_t newPos = 0;
-    while ((newPos = str.find(separator, lastPos)) != std::string::npos) {
-        res.push_back(str.substr(lastPos, newPos - lastPos));
-        lastPos = newPos + 1;
+
+/*****************************************************************************/
+char *pj_make_args (size_t argc, char **argv) {
+/******************************************************************************
+pj_make_args is the inverse of the pj_trim_argc/pj_trim_argv combo: It
+converts free format command line input to something proj_create can consume.
+
+Allocates, and returns, an array of char, large enough to hold a whitespace
+separated copy of the args in argv. It is the duty of the caller to free this
+array.
+******************************************************************************/
+    size_t i, n;
+    char *p;
+
+    for (i = n = 0;  i < argc;  i++)
+        n += strlen (argv[i]);
+
+    p = static_cast<char*>(pj_calloc (n + argc + 1, sizeof (char)));
+    if (nullptr==p)
+        return nullptr;
+    if (0==argc)
+        return p;
+
+    for (i = 0;  i < argc;  i++) {
+        strcat (p, argv[i]);
+        strcat (p, " ");
     }
-    res.push_back(str.substr(lastPos));
-    return res;
+    return pj_shrink (p);
 }
 
-// ---------------------------------------------------------------------------
 
-#ifdef _WIN32
 
-// For some reason, sqlite3_snprintf() in the sqlite3 builds used on AppVeyor
-// doesn't round identically to the Unix builds, and thus breaks a number of
-// unit test. So to avoid this, use the stdlib formatting
-
-std::string toString(int val) {
-    std::ostringstream buffer;
-    buffer.imbue(std::locale::classic());
-    buffer << val;
-    return buffer.str();
+/*****************************************************************************/
+void proj_context_errno_set (PJ_CONTEXT *ctx, int err) {
+/******************************************************************************
+Raise an error directly on a context, without going through a PJ belonging
+to that context.
+******************************************************************************/
+    if (nullptr==ctx)
+        ctx = pj_get_default_ctx();
+    pj_ctx_set_errno (ctx, err);
 }
 
-std::string toString(double val, int precision) {
-    std::ostringstream buffer;
-    buffer.imbue(std::locale::classic());
-    buffer << std::setprecision(precision);
-    buffer << val;
-    auto str = buffer.str();
-    if (precision == 15 && str.find("9999999999") != std::string::npos) {
-        buffer.str("");
-        buffer.clear();
-        buffer << std::setprecision(14);
-        buffer << val;
-        return buffer.str();
-    }
-    return str;
+/*  logging  */
+
+/* pj_vlog resides in pj_log.c and relates to pj_log as vsprintf relates to sprintf */
+void pj_vlog( projCtx ctx, int level, const char *fmt, va_list args );
+
+
+/***************************************************************************************/
+PJ_LOG_LEVEL proj_log_level (PJ_CONTEXT *ctx, PJ_LOG_LEVEL log_level) {
+/****************************************************************************************
+   Set logging level 0-3. Higher number means more debug info. 0 turns it off
+****************************************************************************************/
+    PJ_LOG_LEVEL previous;
+    if (nullptr==ctx)
+        ctx = pj_get_default_ctx();
+    if (nullptr==ctx)
+        return PJ_LOG_TELL;
+    previous = static_cast<PJ_LOG_LEVEL>(abs (ctx->debug_level));
+    if (PJ_LOG_TELL==log_level)
+        return previous;
+    ctx->debug_level = log_level;
+    return previous;
 }
 
-#else
 
-std::string toString(int val) {
-    // use sqlite3 API that is slighly faster than std::ostringstream
-    // with forcing the C locale. sqlite3_snprintf() emulates a C locale.
-    constexpr int BUF_SIZE = 16;
-    char szBuffer[BUF_SIZE];
-    sqlite3_snprintf(BUF_SIZE, szBuffer, "%d", val);
-    return szBuffer;
-}
-
-std::string toString(double val, int precision) {
-    // use sqlite3 API that is slighly faster than std::ostringstream
-    // with forcing the C locale. sqlite3_snprintf() emulates a C locale.
-    constexpr int BUF_SIZE = 32;
-    char szBuffer[BUF_SIZE];
-    sqlite3_snprintf(BUF_SIZE, szBuffer, "%.*g", precision, val);
-    if (precision == 15 && strstr(szBuffer, "9999999999")) {
-        sqlite3_snprintf(BUF_SIZE, szBuffer, "%.14g", val);
-    }
-    return szBuffer;
+/*****************************************************************************/
+void proj_log_error (PJ *P, const char *fmt, ...) {
+/******************************************************************************
+   For reporting the most severe events.
+******************************************************************************/
+    va_list args;
+    va_start( args, fmt );
+    pj_vlog (pj_get_ctx (P), PJ_LOG_ERROR , fmt, args);
+    va_end( args );
 }
 
-#endif
 
-// ---------------------------------------------------------------------------
-
-std::string concat(const char *a, const std::string &b) {
-    std::string res(a);
-    res += b;
-    return res;
+/*****************************************************************************/
+void proj_log_debug (PJ *P, const char *fmt, ...) {
+/******************************************************************************
+   For reporting debugging information.
+******************************************************************************/
+    va_list args;
+    va_start( args, fmt );
+    pj_vlog (pj_get_ctx (P), PJ_LOG_DEBUG_MAJOR , fmt, args);
+    va_end( args );
 }
 
-std::string concat(const char *a, const std::string &b, const char *c) {
-    std::string res(a);
-    res += b;
-    res += c;
-    return res;
-}
 
-// ---------------------------------------------------------------------------
+/*****************************************************************************/
+void proj_log_trace (PJ *P, const char *fmt, ...) {
+/******************************************************************************
+   For reporting embarrasingly detailed debugging information.
+******************************************************************************/
+    va_list args;
+    va_start( args, fmt );
+    pj_vlog (pj_get_ctx (P), PJ_LOG_DEBUG_MINOR , fmt, args);
+    va_end( args );
+}
 
-} // namespace internal
 
-NS_PROJ_END
+/*****************************************************************************/
+void proj_log_func (PJ_CONTEXT *ctx, void *app_data, PJ_LOG_FUNCTION logf) {
+/******************************************************************************
+    Put a new logging function into P's context. The opaque object app_data is
+    passed as first arg at each call to the logger
+******************************************************************************/
+    if (nullptr==ctx)
+        pj_get_default_ctx ();
+    if (nullptr==ctx)
+        return;
+    ctx->app_data = app_data;
+    if (nullptr!=logf)
+        ctx->logger = logf;
+}
diff --git a/src/pj_inv.c b/src/inv.cpp
index aaa8fea9..ba7e6722 100644
--- a/src/pj_inv.c
+++ b/src/inv.cpp
@@ -114,7 +114,7 @@ static PJ_COORD inv_finalize (PJ *P, PJ_COORD coo) {
             return coo;
         if (P->hgridshift)
             coo = proj_trans (P->hgridshift, PJ_FWD, coo);
-        else if (P->helmert || (P->cart_wgs84 != 0 && P->cart != 0)) {
+        else if (P->helmert || (P->cart_wgs84 != nullptr && P->cart != nullptr)) {
             coo = proj_trans (P->cart,       PJ_FWD, coo); /* Go cartesian in local frame */
             if( P->helmert )
                 coo = proj_trans (P->helmert,    PJ_FWD, coo); /* Step into WGS84 */
diff --git a/src/c_api.cpp b/src/iso19111/c_api.cpp
index d0b5d720..d0b5d720 100644
--- a/src/c_api.cpp
+++ b/src/iso19111/c_api.cpp
diff --git a/src/common.cpp b/src/iso19111/common.cpp
index bd690924..bd690924 100644
--- a/src/common.cpp
+++ b/src/iso19111/common.cpp
diff --git a/src/coordinateoperation.cpp b/src/iso19111/coordinateoperation.cpp
index 442a9b78..442a9b78 100644
--- a/src/coordinateoperation.cpp
+++ b/src/iso19111/coordinateoperation.cpp
diff --git a/src/coordinatesystem.cpp b/src/iso19111/coordinatesystem.cpp
index a3ad04e0..a3ad04e0 100644
--- a/src/coordinatesystem.cpp
+++ b/src/iso19111/coordinatesystem.cpp
diff --git a/src/crs.cpp b/src/iso19111/crs.cpp
index a05470ff..a05470ff 100644
--- a/src/crs.cpp
+++ b/src/iso19111/crs.cpp
diff --git a/src/datum.cpp b/src/iso19111/datum.cpp
index 16e86296..16e86296 100644
--- a/src/datum.cpp
+++ b/src/iso19111/datum.cpp
diff --git a/src/factory.cpp b/src/iso19111/factory.cpp
index 47d31db9..47d31db9 100644
--- a/src/factory.cpp
+++ b/src/iso19111/factory.cpp
diff --git a/src/iso19111/internal.cpp b/src/iso19111/internal.cpp
new file mode 100644
index 00000000..c43605d1
--- /dev/null
+++ b/src/iso19111/internal.cpp
@@ -0,0 +1,374 @@
+/******************************************************************************
+ *
+ * Project:  PROJ
+ * Purpose:  ISO19111:2018 implementation
+ * Author:   Even Rouault <even dot rouault at spatialys dot com>
+ *
+ ******************************************************************************
+ * Copyright (c) 2018, Even Rouault <even dot rouault at spatialys dot com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ ****************************************************************************/
+
+#ifndef FROM_PROJ_CPP
+#define FROM_PROJ_CPP
+#endif
+
+#include "proj/internal/internal.hpp"
+
+#include <cstdint>
+#include <cstring>
+#ifdef _MSC_VER
+#include <string.h>
+#else
+#include <strings.h>
+#endif
+#include <exception>
+#include <iomanip> // std::setprecision
+#include <locale>
+#include <sstream> // std::istringstream and std::ostringstream
+#include <string>
+
+#include "sqlite3.h"
+
+NS_PROJ_START
+
+namespace internal {
+
+// ---------------------------------------------------------------------------
+
+/**
+ * Replace all occurrences of before with after.
+ */
+std::string replaceAll(const std::string &str, const std::string &before,
+                       const std::string &after) {
+    std::string ret(str);
+    const size_t nBeforeSize = before.size();
+    const size_t nAfterSize = after.size();
+    if (nBeforeSize) {
+        size_t nStartPos = 0;
+        while ((nStartPos = ret.find(before, nStartPos)) != std::string::npos) {
+            ret.replace(nStartPos, nBeforeSize, after);
+            nStartPos += nAfterSize;
+        }
+    }
+    return ret;
+}
+
+// ---------------------------------------------------------------------------
+
+inline static bool EQUALN(const char *a, const char *b, size_t size) {
+#ifdef _MSC_VER
+    return _strnicmp(a, b, size) == 0;
+#else
+    return strncasecmp(a, b, size) == 0;
+#endif
+}
+
+/**
+ * Case-insensitive equality test
+ */
+bool ci_equal(const std::string &a, const std::string &b) noexcept {
+    const auto size = a.size();
+    if (size != b.size()) {
+        return false;
+    }
+    return EQUALN(a.c_str(), b.c_str(), size);
+}
+
+bool ci_equal(const std::string &a, const char *b) noexcept {
+    const auto size = a.size();
+    if (size != strlen(b)) {
+        return false;
+    }
+    return EQUALN(a.c_str(), b, size);
+}
+
+bool ci_equal(const char *a, const char *b) noexcept {
+    const auto size = strlen(a);
+    if (size != strlen(b)) {
+        return false;
+    }
+    return EQUALN(a, b, size);
+}
+
+// ---------------------------------------------------------------------------
+
+bool ci_less(const std::string &a, const std::string &b) noexcept {
+#ifdef _MSC_VER
+    return _stricmp(a.c_str(), b.c_str()) < 0;
+#else
+    return strcasecmp(a.c_str(), b.c_str()) < 0;
+#endif
+}
+
+// ---------------------------------------------------------------------------
+
+/**
+ * Convert to lower case.
+ */
+
+std::string tolower(const std::string &str)
+
+{
+    std::string ret(str);
+    for (size_t i = 0; i < ret.size(); i++)
+        ret[i] = static_cast<char>(::tolower(ret[i]));
+    return ret;
+}
+
+// ---------------------------------------------------------------------------
+
+/**
+ * Convert to upper case.
+ */
+
+std::string toupper(const std::string &str)
+
+{
+    std::string ret(str);
+    for (size_t i = 0; i < ret.size(); i++)
+        ret[i] = static_cast<char>(::toupper(ret[i]));
+    return ret;
+}
+
+// ---------------------------------------------------------------------------
+
+/** Strip leading and trailing double quote characters */
+std::string stripQuotes(const std::string &str) {
+    if (str.size() >= 2 && str[0] == '"' && str.back() == '"') {
+        return str.substr(1, str.size() - 2);
+    }
+    return str;
+}
+
+// ---------------------------------------------------------------------------
+
+size_t ci_find(const std::string &str, const char *needle) noexcept {
+    const size_t needleSize = strlen(needle);
+    for (size_t i = 0; i + needleSize <= str.size(); i++) {
+        if (EQUALN(str.c_str() + i, needle, needleSize)) {
+            return i;
+        }
+    }
+    return std::string::npos;
+}
+
+// ---------------------------------------------------------------------------
+
+size_t ci_find(const std::string &str, const std::string &needle,
+               size_t startPos) noexcept {
+    const size_t needleSize = needle.size();
+    for (size_t i = startPos; i + needleSize <= str.size(); i++) {
+        if (EQUALN(str.c_str() + i, needle.c_str(), needleSize)) {
+            return i;
+        }
+    }
+    return std::string::npos;
+}
+
+// ---------------------------------------------------------------------------
+
+/*
+bool starts_with(const std::string &str, const std::string &prefix) noexcept {
+    if (str.size() < prefix.size()) {
+        return false;
+    }
+    return std::memcmp(str.c_str(), prefix.c_str(), prefix.size()) == 0;
+}
+*/
+
+// ---------------------------------------------------------------------------
+
+/*
+bool starts_with(const std::string &str, const char *prefix) noexcept {
+    const size_t prefixSize = std::strlen(prefix);
+    if (str.size() < prefixSize) {
+        return false;
+    }
+    return std::memcmp(str.c_str(), prefix, prefixSize) == 0;
+}
+*/
+
+// ---------------------------------------------------------------------------
+
+bool ci_starts_with(const char *str, const char *prefix) noexcept {
+    const auto str_size = strlen(str);
+    const auto prefix_size = strlen(prefix);
+    if (str_size < prefix_size) {
+        return false;
+    }
+    return EQUALN(str, prefix, prefix_size);
+}
+
+// ---------------------------------------------------------------------------
+
+bool ci_starts_with(const std::string &str,
+                    const std::string &prefix) noexcept {
+    if (str.size() < prefix.size()) {
+        return false;
+    }
+    return EQUALN(str.c_str(), prefix.c_str(), prefix.size());
+}
+
+// ---------------------------------------------------------------------------
+
+bool ends_with(const std::string &str, const std::string &suffix) noexcept {
+    if (str.size() < suffix.size()) {
+        return false;
+    }
+    return std::memcmp(str.c_str() + str.size() - suffix.size(), suffix.c_str(),
+                       suffix.size()) == 0;
+}
+
+// ---------------------------------------------------------------------------
+
+double c_locale_stod(const std::string &s) {
+
+    const auto s_size = s.size();
+    // Fast path
+    if (s_size > 0 && s_size < 15) {
+        std::int64_t acc = 0;
+        std::int64_t div = 1;
+        bool afterDot = false;
+        size_t i = 0;
+        if (s[0] == '-') {
+            ++i;
+            div = -1;
+        } else if (s[0] == '+') {
+            ++i;
+        }
+        for (; i < s_size; ++i) {
+            const auto ch = s[i];
+            if (ch >= '0' && ch <= '9') {
+                acc = acc * 10 + ch - '0';
+                if (afterDot) {
+                    div *= 10;
+                }
+            } else if (ch == '.') {
+                afterDot = true;
+            } else {
+                div = 0;
+            }
+        }
+        if (div) {
+            return static_cast<double>(acc) / div;
+        }
+    }
+
+    std::istringstream iss(s);
+    iss.imbue(std::locale::classic());
+    double d;
+    iss >> d;
+    if (!iss.eof() || iss.fail()) {
+        throw std::invalid_argument("non double value");
+    }
+    return d;
+}
+
+// ---------------------------------------------------------------------------
+
+std::vector<std::string> split(const std::string &str, char separator) {
+    std::vector<std::string> res;
+    size_t lastPos = 0;
+    size_t newPos = 0;
+    while ((newPos = str.find(separator, lastPos)) != std::string::npos) {
+        res.push_back(str.substr(lastPos, newPos - lastPos));
+        lastPos = newPos + 1;
+    }
+    res.push_back(str.substr(lastPos));
+    return res;
+}
+
+// ---------------------------------------------------------------------------
+
+#ifdef _WIN32
+
+// For some reason, sqlite3_snprintf() in the sqlite3 builds used on AppVeyor
+// doesn't round identically to the Unix builds, and thus breaks a number of
+// unit test. So to avoid this, use the stdlib formatting
+
+std::string toString(int val) {
+    std::ostringstream buffer;
+    buffer.imbue(std::locale::classic());
+    buffer << val;
+    return buffer.str();
+}
+
+std::string toString(double val, int precision) {
+    std::ostringstream buffer;
+    buffer.imbue(std::locale::classic());
+    buffer << std::setprecision(precision);
+    buffer << val;
+    auto str = buffer.str();
+    if (precision == 15 && str.find("9999999999") != std::string::npos) {
+        buffer.str("");
+        buffer.clear();
+        buffer << std::setprecision(14);
+        buffer << val;
+        return buffer.str();
+    }
+    return str;
+}
+
+#else
+
+std::string toString(int val) {
+    // use sqlite3 API that is slighly faster than std::ostringstream
+    // with forcing the C locale. sqlite3_snprintf() emulates a C locale.
+    constexpr int BUF_SIZE = 16;
+    char szBuffer[BUF_SIZE];
+    sqlite3_snprintf(BUF_SIZE, szBuffer, "%d", val);
+    return szBuffer;
+}
+
+std::string toString(double val, int precision) {
+    // use sqlite3 API that is slighly faster than std::ostringstream
+    // with forcing the C locale. sqlite3_snprintf() emulates a C locale.
+    constexpr int BUF_SIZE = 32;
+    char szBuffer[BUF_SIZE];
+    sqlite3_snprintf(BUF_SIZE, szBuffer, "%.*g", precision, val);
+    if (precision == 15 && strstr(szBuffer, "9999999999")) {
+        sqlite3_snprintf(BUF_SIZE, szBuffer, "%.14g", val);
+    }
+    return szBuffer;
+}
+
+#endif
+
+// ---------------------------------------------------------------------------
+
+std::string concat(const char *a, const std::string &b) {
+    std::string res(a);
+    res += b;
+    return res;
+}
+
+std::string concat(const char *a, const std::string &b, const char *c) {
+    std::string res(a);
+    res += b;
+    res += c;
+    return res;
+}
+
+// ---------------------------------------------------------------------------
+
+} // namespace internal
+
+NS_PROJ_END
diff --git a/src/io.cpp b/src/iso19111/io.cpp
index fe3680fb..7f68a579 100644
--- a/src/io.cpp
+++ b/src/iso19111/io.cpp
@@ -60,8 +60,8 @@
 
 #include "proj_constants.h"
 
-#include "pj_wkt1_parser.h"
-#include "pj_wkt2_parser.h"
+#include "wkt1_parser.h"
+#include "wkt2_parser.h"
 
 // PROJ include order is sensitive
 // clang-format off
diff --git a/src/metadata.cpp b/src/iso19111/metadata.cpp
index 2be9dac3..2be9dac3 100644
--- a/src/metadata.cpp
+++ b/src/iso19111/metadata.cpp
diff --git a/src/static.cpp b/src/iso19111/static.cpp
index 5de046f1..5de046f1 100644
--- a/src/static.cpp
+++ b/src/iso19111/static.cpp
diff --git a/src/util.cpp b/src/iso19111/util.cpp
index ac6357a2..ac6357a2 100644
--- a/src/util.cpp
+++ b/src/iso19111/util.cpp
diff --git a/src/jniproj.c b/src/jniproj.cpp
index 67aa2478..67aa2478 100644
--- a/src/jniproj.c
+++ b/src/jniproj.cpp
diff --git a/src/lib_proj.cmake b/src/lib_proj.cmake
index 4f29f4d5..767106e6 100644
--- a/src/lib_proj.cmake
+++ b/src/lib_proj.cmake
@@ -54,217 +54,177 @@ endif()
 ##############################################
 ###  library source list and include_list  ###
 ##############################################
-SET(SRC_LIBPROJ_PJ
-        nad_init.c
-        PJ_aea.c
-        PJ_aeqd.c
-        PJ_affine.c
-        PJ_airy.c
-        PJ_aitoff.c
-        PJ_august.c
-        PJ_axisswap.c
-        PJ_bacon.c
-        PJ_bertin1953.c
-        PJ_bipc.c
-        PJ_boggs.c
-        PJ_bonne.c
-        PJ_calcofi.c
-        PJ_cart.c
-        PJ_cass.c
-        PJ_cc.c
-        PJ_ccon.c
-        PJ_cea.c
-        PJ_chamb.c
-        PJ_collg.c
-        PJ_comill.c
-        PJ_crast.c
-        PJ_deformation.c
-        PJ_denoy.c
-        PJ_eck1.c
-        PJ_eck2.c
-        PJ_eck3.c
-        PJ_eck4.c
-        PJ_eck5.c
-        PJ_eqc.c
-        PJ_eqdc.c
-        PJ_eqearth.c
-        PJ_fahey.c
-        PJ_fouc_s.c
-        PJ_gall.c
-        PJ_geoc.c
-        PJ_geos.c
-        PJ_gins8.c
-        PJ_gnom.c
-        PJ_gn_sinu.c
-        PJ_goode.c
-        PJ_gstmerc.c
-        PJ_hammer.c
-        PJ_hatano.c
-        PJ_helmert.c
-        PJ_hgridshift.c
-        PJ_horner.c
-        PJ_igh.c
-        PJ_isea.c
-        PJ_imw_p.c
-        PJ_krovak.c
-        PJ_labrd.c
-        PJ_laea.c
-        PJ_lagrng.c
-        PJ_larr.c
-        PJ_lask.c
-        PJ_latlong.c
-        PJ_lcca.c
-        PJ_lcc.c
-        PJ_loxim.c
-        PJ_lsat.c
-        PJ_misrsom.c
-        PJ_mbt_fps.c
-        PJ_mbtfpp.c
-        PJ_mbtfpq.c
-        PJ_merc.c
-        PJ_mill.c
-        PJ_mod_ster.c
-        PJ_moll.c
-        PJ_molodensky.c
-        PJ_natearth.c
-        PJ_natearth2.c
-        PJ_nell.c
-        PJ_nell_h.c
-        PJ_nocol.c
-        PJ_nsper.c
-        PJ_nzmg.c
-        PJ_ob_tran.c
-        PJ_ocea.c
-        PJ_oea.c
-        PJ_omerc.c
-        PJ_ortho.c
-        PJ_patterson.c
-        PJ_pipeline.c
-        PJ_poly.c
-        PJ_putp2.c
-        PJ_putp3.c
-        PJ_putp4p.c
-        PJ_putp5.c
-        PJ_putp6.c
-        PJ_qsc.c
-        PJ_robin.c
-        PJ_rpoly.c
-        PJ_sch.c
-        PJ_sconics.c
-        PJ_somerc.c
-        PJ_sterea.c
-        PJ_stere.c
-        PJ_sts.c
-        PJ_tcc.c
-        PJ_tcea.c
-        PJ_times.c
-        PJ_tmerc.c
-        PJ_tobmerc.c
-        PJ_tpeqd.c
-        PJ_unitconvert.c
-        PJ_urm5.c
-        PJ_urmfps.c
-        PJ_vandg.c
-        PJ_vandg2.c
-        PJ_vandg4.c
-        PJ_vgridshift.c
-        PJ_wag2.c
-        PJ_wag3.c
-        PJ_wag7.c
-        PJ_wink1.c
-        PJ_wink2.c
-        proj_etmerc.c
+
+SET(SRC_LIBPROJ_PROJECTIONS
+        projections/aeqd.cpp
+        projections/gnom.cpp
+        projections/laea.cpp
+        projections/mod_ster.cpp
+        projections/nsper.cpp
+        projections/nzmg.cpp
+        projections/ortho.cpp
+        projections/stere.cpp
+        projections/sterea.cpp
+        projections/aea.cpp
+        projections/bipc.cpp
+        projections/bonne.cpp
+        projections/eqdc.cpp
+        projections/isea.cpp
+        projections/ccon.cpp
+        projections/imw_p.cpp
+        projections/krovak.cpp
+        projections/lcc.cpp
+        projections/poly.cpp
+        projections/rpoly.cpp
+        projections/sconics.cpp
+        projections/rouss.cpp
+        projections/cass.cpp
+        projections/cc.cpp
+        projections/cea.cpp
+        projections/eqc.cpp
+        projections/gall.cpp
+        projections/labrd.cpp
+        projections/lsat.cpp
+        projections/misrsom.cpp
+        projections/merc.cpp
+        projections/mill.cpp
+        projections/ocea.cpp
+        projections/omerc.cpp
+        projections/somerc.cpp
+        projections/tcc.cpp
+        projections/tcea.cpp
+        projections/times.cpp
+        projections/tmerc.cpp
+        projections/tobmerc.cpp
+        projections/airy.cpp
+        projections/aitoff.cpp
+        projections/august.cpp
+        projections/bacon.cpp
+        projections/bertin1953.cpp
+        projections/chamb.cpp
+        projections/hammer.cpp
+        projections/lagrng.cpp
+        projections/larr.cpp
+        projections/lask.cpp
+        projections/latlong.cpp
+        projections/nicol.cpp
+        projections/ob_tran.cpp
+        projections/oea.cpp
+        projections/tpeqd.cpp
+        projections/vandg.cpp
+        projections/vandg2.cpp
+        projections/vandg4.cpp
+        projections/wag7.cpp
+        projections/lcca.cpp
+        projections/geos.cpp
+        projections/etmerc.cpp
+        projections/boggs.cpp
+        projections/collg.cpp
+        projections/comill.cpp
+        projections/crast.cpp
+        projections/denoy.cpp
+        projections/eck1.cpp
+        projections/eck2.cpp
+        projections/eck3.cpp
+        projections/eck4.cpp
+        projections/eck5.cpp
+        projections/fahey.cpp
+        projections/fouc_s.cpp
+        projections/gins8.cpp
+        projections/gstmerc.cpp
+        projections/gn_sinu.cpp
+        projections/goode.cpp
+        projections/igh.cpp
+        projections/hatano.cpp
+        projections/loxim.cpp
+        projections/mbt_fps.cpp
+        projections/mbtfpp.cpp
+        projections/mbtfpq.cpp
+        projections/moll.cpp
+        projections/nell.cpp
+        projections/nell_h.cpp
+        projections/patterson.cpp
+        projections/putp2.cpp
+        projections/putp3.cpp
+        projections/putp4p.cpp
+        projections/putp5.cpp
+        projections/putp6.cpp
+        projections/qsc.cpp
+        projections/robin.cpp
+        projections/sch.cpp
+        projections/sts.cpp
+        projections/urm5.cpp
+        projections/urmfps.cpp
+        projections/wag2.cpp
+        projections/wag3.cpp
+        projections/wink1.cpp
+        projections/wink2.cpp
+        projections/healpix.cpp
+        projections/natearth.cpp
+        projections/natearth2.cpp
+        projections/calcofi.cpp
+        projections/eqearth.cpp
 )
 
-SET(SRC_LIBPROJ_CORE
-        aasincos.c
-        adjlon.c
-        bch2bps.c
-        bchgen.c
-        biveval.c
-        dmstor.c
-        emess.c
-        emess.h
-        geocent.c
-        geocent.h
-        geodesic.c
-        mk_cheby.c
-        nad_cvt.c
-        nad_init.c
-        nad_intr.c
-        pj_apply_gridshift.c
-        pj_apply_vgridshift.c
-        pj_auth.c
-        pj_ctx.c
-        pj_fileapi.c
-        pj_datum_set.c
-        pj_datums.c
-        pj_deriv.c
-        pj_ell_set.c
-        pj_ellps.c
-        pj_errno.c
-        pj_factors.c
-        pj_fwd.c
-        pj_gauss.c
-        pj_gc_reader.c
-        pj_geocent.c
-        pj_gridcatalog.c
-        pj_gridinfo.c
-        pj_gridlist.c
-        PJ_healpix.c
-        pj_init.c
-        pj_initcache.c
-        pj_inv.c
-        pj_list.c
-        pj_list.h
-        pj_log.c
-        pj_malloc.c
-        pj_math.c
-        pj_mlfn.c
-        pj_msfn.c
-        pj_mutex.c
-        proj_4D_api.c
-        pj_internal.c
-        proj_internal.h
-        pj_open_lib.c
-        pj_param.c
-        pj_phi2.c
-        pj_pr_list.c
-        pj_qsfn.c
-        pj_release.c
-        pj_strerrno.c
-        pj_transform.c
-        pj_tsfn.c
-        pj_units.c
-        pj_utils.c
-        pj_zpoly1.c
-        proj_mdist.c
-        proj_math.h
-        proj_rouss.c
-        rtodms.c
-        vector1.c
-        pj_strtod.c
-        pj_wkt1_generated_parser.c
-        pj_wkt2_generated_parser.c
-        ${CMAKE_CURRENT_BINARY_DIR}/proj_config.h
+SET(SRC_LIBPROJ_CONVERSIONS
+        conversions/axisswap.cpp
+        conversions/cart.cpp
+        conversions/geoc.cpp
+        conversions/geocent.cpp
+        conversions/unitconvert.cpp
+)
+
+SET(SRC_LIBPROJ_TRANSFORMATIONS
+        transformations/affine.cpp
+        transformations/deformation.cpp
+        transformations/helmert.cpp
+        transformations/hgridshift.cpp
+        transformations/horner.cpp
+        transformations/molodensky.cpp
+        transformations/vgridshift.cpp
 )
 
-set(SRC_LIBPROJ_CPP
-        static.cpp
-        common.cpp
-        coordinateoperation.cpp
-        coordinatesystem.cpp
-        crs.cpp
-        datum.cpp
-        io.cpp
-        metadata.cpp
-        util.cpp
+SET(SRC_LIBPROJ_ISO19111
+        iso19111/static.cpp
+        iso19111/util.cpp
+        iso19111/metadata.cpp
+        iso19111/common.cpp
+        iso19111/crs.cpp
+        iso19111/datum.cpp
+        iso19111/coordinatesystem.cpp
+        iso19111/coordinateoperation.cpp
+        iso19111/io.cpp
+        iso19111/internal.cpp
+        iso19111/factory.cpp
+        iso19111/c_api.cpp
+)
+
+SET(SRC_LIBPROJ_CORE
+        pj_list.h proj_internal.h proj_math.h projects.h
+        aasincos.cpp adjlon.cpp bch2bps.cpp bchgen.cpp
+        biveval.cpp dmstor.cpp mk_cheby.cpp auth.cpp
+        deriv.cpp ell_set.cpp ellps.cpp errno.cpp
+        factors.cpp fwd.cpp init.cpp inv.cpp
+        list.cpp malloc.cpp mlfn.cpp msfn.cpp proj_mdist.cpp
+        open_lib.cpp param.cpp phi2.cpp pr_list.cpp
+        qsfn.cpp strerrno.cpp
+        tsfn.cpp units.cpp ctx.cpp log.cpp zpoly1.cpp rtodms.cpp
+        vector1.cpp release.cpp gauss.cpp
+        fileapi.cpp
+        gc_reader.cpp gridcatalog.cpp
+        nad_cvt.cpp nad_init.cpp nad_intr.cpp
+        apply_gridshift.cpp datums.cpp datum_set.cpp transform.cpp
+        geocent.cpp geocent.h utils.cpp gridinfo.cpp gridlist.cpp
+        jniproj.cpp mutex.cpp initcache.cpp apply_vgridshift.cpp geodesic.c
+        strtod.cpp math.cpp
+        4D_api.cpp pipeline.cpp
         internal.cpp
-        factory.cpp
-        c_api.cpp
-        pj_wkt_parser.cpp
-        pj_wkt1_parser.cpp
-        pj_wkt2_parser.cpp
+        wkt_parser.hpp wkt_parser.cpp
+        wkt1_parser.h wkt1_parser.cpp
+        wkt1_generated_parser.h wkt1_generated_parser.c
+        wkt2_parser.h wkt2_parser.cpp
+        wkt2_generated_parser.h wkt2_generated_parser.c
+        ${CMAKE_CURRENT_BINARY_DIR}/proj_config.h
 )
 
 set(HEADERS_LIBPROJ
@@ -278,8 +238,10 @@ set(HEADERS_LIBPROJ
 # Group source files for IDE source explorers (e.g. Visual Studio)
 source_group("Header Files" FILES ${HEADERS_LIBPROJ})
 source_group("Source Files\\Core" FILES ${SRC_LIBPROJ_CORE})
-source_group("Source Files\\PJ" FILES ${SRC_LIBPROJ_PJ})
-source_group("Source Files\\C++" FILES ${SRC_LIBPROJ_CPP})
+source_group("Source Files\\Conversions" FILES ${SRC_LIBPROJ_CONVERSIONS})
+source_group("Source Files\\Projections" FILES ${SRC_LIBPROJ_PROJECTIONS})
+source_group("Source Files\\Transformations" FILES ${SRC_LIBPROJ_TRANSFORMATIONS})
+source_group("Source Files\\ISO19111" FILES ${SRC_LIBPROJ_ISO19111})
 
 include_directories(${CMAKE_SOURCE_DIR}/include)
 
@@ -301,7 +263,7 @@ endif(JNI_SUPPORT AND NOT JNI_FOUND)
 boost_report_value(JNI_SUPPORT)
 if(JNI_SUPPORT)
   set(SRC_LIBPROJ_CORE ${SRC_LIBPROJ_CORE}
-                       jniproj.c )
+                       jniproj.cpp )
   set(HEADERS_LIBPROJ ${HEADERS_LIBPROJ}
                         org_proj4_PJ.h)
   source_group("Source Files\\JNI" FILES ${SRC_LIBPROJ_JNI})
@@ -313,7 +275,12 @@ endif(JNI_SUPPORT)
 #################################################
 ## targets: libproj and proj_config.h
 #################################################
-set(ALL_LIBPROJ_SOURCES ${SRC_LIBPROJ_PJ} ${SRC_LIBPROJ_CORE} ${SRC_LIBPROJ_CPP})
+set(ALL_LIBPROJ_SOURCES ${SRC_LIBPROJ_CORE}
+                        ${SRC_LIBPROJ_CONVERSIONS}
+                        ${SRC_LIBPROJ_PROJECTIONS}
+                        ${SRC_LIBPROJ_TRANSFORMATIONS}
+                        ${SRC_LIBPROJ_ISO19111}
+)
 set(ALL_LIBPROJ_HEADERS ${HEADERS_LIBPROJ} )
 
 # Core targets configuration
diff --git a/src/pj_list.c b/src/list.cpp
index 33313875..73ca5f86 100644
--- a/src/pj_list.c
+++ b/src/list.cpp
@@ -9,12 +9,12 @@
 
 
 /* Generate prototypes for projection functions */
-#define PROJ_HEAD(id, name) struct PJconsts *pj_##id(struct PJconsts*);
+#define PROJ_HEAD(id, name) extern "C" struct PJconsts *pj_##id(struct PJconsts*);
 #include "pj_list.h"
 #undef PROJ_HEAD
 
 /* Generate extern declarations for description strings */
-#define PROJ_HEAD(id, name) extern const char * const pj_s_##id;
+#define PROJ_HEAD(id, name) extern "C" const char * const pj_s_##id;
 #include "pj_list.h"
 #undef PROJ_HEAD
 
@@ -22,7 +22,7 @@
 #define PROJ_HEAD(id, name) {#id, pj_##id, &pj_s_##id},
 const struct PJ_LIST pj_list[] = {
 #include "pj_list.h"
-    {0,     0,  0},
+    {nullptr,     nullptr,  nullptr},
 };
 #undef PROJ_HEAD
 
diff --git a/src/pj_log.c b/src/log.cpp
index 6654691c..0f81dc13 100644
--- a/src/pj_log.c
+++ b/src/log.cpp
@@ -68,7 +68,7 @@ void pj_vlog( projCtx ctx, int level, const char *fmt, va_list args )
         return;
 
     msg_buf = (char *) malloc(100000);
-    if( msg_buf == NULL )
+    if( msg_buf == nullptr )
         return;
 
     /* we should use vsnprintf where available once we add configure detect.*/
diff --git a/src/pj_malloc.c b/src/malloc.cpp
index c45da85d..c8681570 100644
--- a/src/pj_malloc.c
+++ b/src/malloc.cpp
@@ -95,8 +95,8 @@ It allocates space for an array of <n> elements of size <size>.
 The array is initialized to zeros.
 ***********************************************************************/
     void *res = pj_malloc (n*size);
-    if (0==res)
-        return 0;
+    if (nullptr==res)
+        return nullptr;
     memset (res, 0, n*size);
     return res;
 }
@@ -128,10 +128,10 @@ pointer" to signal an error in a multi level allocation:
     return p;  // success
 
 ***********************************************************************/
-    if (0==ptr)
-        return 0;
+    if (nullptr==ptr)
+        return nullptr;
     pj_dalloc (ptr);
-    return 0;
+    return nullptr;
 }
 
 /**********************************************************************/
@@ -139,7 +139,7 @@ char *pj_strdup(const char *str)
 /**********************************************************************/
 {
     size_t len = strlen(str) + 1;
-    char *dup = pj_malloc(len);
+    char *dup = static_cast<char*>(pj_malloc(len));
     if (dup)
         memcpy(dup, str, len);
     return dup;
@@ -161,7 +161,7 @@ void *pj_dealloc_params (PJ_CONTEXT *ctx, paralist *start, int errlev) {
         pj_dealloc(t);
     }
     pj_ctx_set_errno (ctx, errlev);
-    return (void *) 0;
+    return (void *) nullptr;
 }
 
 
@@ -178,7 +178,7 @@ void *pj_dealloc_params (PJ_CONTEXT *ctx, paralist *start, int errlev) {
 /************************************************************************/
 
 void pj_free(PJ *P) {
-    if (0==P)
+    if (nullptr==P)
         return;
     /* free projection parameters - all the hard work is done by */
     /* pj_default_destructor, which is supposed */
@@ -192,7 +192,7 @@ void pj_free(PJ *P) {
 
 
 /*****************************************************************************/
-void *pj_default_destructor (PJ *P, int errlev) {   /* Destructor */
+PJ *pj_default_destructor (PJ *P, int errlev) {   /* Destructor */
 /*****************************************************************************
     Does memory deallocation for "plain" PJ objects, i.e. that vast majority
     of PJs where the opaque object does not contain any additionally
@@ -205,8 +205,8 @@ void *pj_default_destructor (PJ *P, int errlev) {   /* Destructor */
     if (0!=errlev)
         pj_ctx_set_errno (pj_get_ctx(P), errlev);
 
-    if (0==P)
-        return 0;
+    if (nullptr==P)
+        return nullptr;
 
     /* free grid lists */
     pj_dealloc( P->gridlist );
@@ -234,6 +234,7 @@ void *pj_default_destructor (PJ *P, int errlev) {   /* Destructor */
     pj_free (P->hgridshift);
     pj_free (P->vgridshift);
 
-    pj_dealloc (P->opaque);
-    return pj_dealloc(P);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque));
+    pj_dealloc(P);
+    return nullptr;
 }
diff --git a/src/pj_math.c b/src/math.cpp
index 540ab9eb..540ab9eb 100644
--- a/src/pj_math.c
+++ b/src/math.cpp
diff --git a/src/mk_cheby.c b/src/mk_cheby.cpp
index a2f90bef..5e6bfef0 100644
--- a/src/mk_cheby.c
+++ b/src/mk_cheby.cpp
@@ -23,36 +23,36 @@ makeT(int nru, int nrv) {
     int i;
 
     if (!(T = (Tseries *)pj_malloc(sizeof(Tseries))))
-        return 0;
+        return nullptr;
     if (!(T->cu = (struct PW_COEF *)pj_malloc(sizeof(struct PW_COEF) * nru))) {
         pj_dalloc(T);
-        return 0;
+        return nullptr;
     }
     if (!(T->cv = (struct PW_COEF *)pj_malloc(sizeof(struct PW_COEF) * nrv))) {
         pj_dalloc(T->cu);
         pj_dalloc(T);
-        return 0;
+        return nullptr;
     }
 
     for (i = 0; i < nru; ++i)
-        T->cu[i].c = 0;
+        T->cu[i].c = nullptr;
     for (i = 0; i < nrv; ++i)
-        T->cv[i].c = 0;
+        T->cv[i].c = nullptr;
     return T;
 }
 Tseries *
 mk_cheby(projUV a, projUV b, double res, projUV *resid, projUV (*func)(projUV), 
          int nu, int nv, int power) {
     int j, i, nru, nrv, *ncu, *ncv;
-    Tseries *T = NULL;
+    Tseries *T = nullptr;
     projUV **w;
     double cutres;
 
     if (!(w = (projUV **)vector2(nu, nv, sizeof(projUV))))
-        return 0;
+        return nullptr;
     if (!(ncu = (int *)vector1(nu + nv, sizeof(int)))) {
         freev2((void **)w, nu);
-        return 0;
+        return nullptr;
     }
     ncv = ncu + nu;
     if (!bchgen(a, b, nu, nv, w, func)) {
@@ -106,7 +106,7 @@ mk_cheby(projUV a, projUV b, double res, projUV *resid, projUV (*func)(projUV),
                 if (ncu[j]) nru = j + 1;	/* update row max */
                 if (ncv[j]) nrv = j + 1;
             }
-            if ((T = makeT(nru, nrv)) != NULL ) {
+            if ((T = makeT(nru, nrv)) != nullptr ) {
                 T->a = a;
                 T->b = b;
                 T->mu = nru - 1;
@@ -137,7 +137,7 @@ mk_cheby(projUV a, projUV b, double res, projUV *resid, projUV (*func)(projUV),
                     }
                 }
             }
-        } else if ((T = makeT(nru, nrv)) != NULL) {
+        } else if ((T = makeT(nru, nrv)) != nullptr) {
             /* else make returned Chebyshev coefficient structure */
             T->mu = nru - 1; /* save row degree */
             T->mv = nrv - 1;
@@ -184,7 +184,7 @@ mk_cheby(projUV a, projUV b, double res, projUV *resid, projUV (*func)(projUV),
                 pj_dalloc(T->cv[i].c);
         pj_dalloc(T);
     }
-    T = 0;
+    T = nullptr;
   gohome:
     freev2((void **) w, nu);
     pj_dalloc(ncu);
diff --git a/src/pj_mlfn.c b/src/mlfn.cpp
index 02e05c3a..e032e642 100644
--- a/src/pj_mlfn.c
+++ b/src/mlfn.cpp
@@ -27,8 +27,8 @@ double *pj_enfn(double es) {
     double t, *en;
 
 	en = (double *) pj_malloc(EN_SIZE * sizeof (double));
-	if (0==en)
-	    return 0;
+	if (nullptr==en)
+	    return nullptr;
 
     en[0] = C00 - es * (C02 + es * (C04 + es * (C06 + es * C08)));
     en[1] = es * (C22 - es * (C04 + es * (C06 + es * C08)));
diff --git a/src/pj_msfn.c b/src/msfn.cpp
index 999e73a7..999e73a7 100644
--- a/src/pj_msfn.c
+++ b/src/msfn.cpp
diff --git a/src/pj_mutex.c b/src/mutex.cpp
index dc4a441b..3752324c 100644
--- a/src/pj_mutex.c
+++ b/src/mutex.cpp
@@ -34,7 +34,9 @@
 #endif
 
 /* For PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP */
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 
 #ifndef _WIN32
 #include "proj_config.h"
@@ -106,7 +108,14 @@ void pj_cleanup_lock()
 #include "pthread.h"
 
 #ifdef PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wzero-as-null-pointer-constant"
+#endif
 static pthread_mutex_t core_lock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
 #else
 static pthread_mutex_t core_lock;
 
diff --git a/src/nad_cvt.c b/src/nad_cvt.cpp
index ec4a2b47..ec4a2b47 100644
--- a/src/nad_cvt.c
+++ b/src/nad_cvt.cpp
diff --git a/src/nad_init.c b/src/nad_init.cpp
index 8b024ac7..1e2b150d 100644
--- a/src/nad_init.c
+++ b/src/nad_init.cpp
@@ -83,11 +83,11 @@ int nad_ctable_load( projCtx ctx, struct CTABLE *ct, PAFile fid )
     /* read all the actual shift values */
     a_size = ct->lim.lam * ct->lim.phi;
     ct->cvs = (FLP *) pj_malloc(sizeof(FLP) * a_size);
-    if( ct->cvs == NULL 
+    if( ct->cvs == nullptr 
         || pj_ctx_fread(ctx, ct->cvs, sizeof(FLP), a_size, fid) != a_size )
     {
         pj_dalloc( ct->cvs );
-        ct->cvs = NULL;
+        ct->cvs = nullptr;
 
         pj_log( ctx, PJ_LOG_ERROR, 
                 "ctable loading failed on fread() - binary incompatible?" );
@@ -111,12 +111,12 @@ struct CTABLE *nad_ctable_init( projCtx ctx, PAFile fid )
 
     /* read the table header */
     ct = (struct CTABLE *) pj_malloc(sizeof(struct CTABLE));
-    if( ct == NULL 
+    if( ct == nullptr 
         || pj_ctx_fread( ctx, ct, sizeof(struct CTABLE), 1, fid ) != 1 )
     {
         pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
         pj_dalloc( ct );
-        return NULL;
+        return nullptr;
     }
 
     /* do some minimal validation to ensure the structure isn't corrupt */
@@ -125,7 +125,7 @@ struct CTABLE *nad_ctable_init( projCtx ctx, PAFile fid )
     {
         pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
         pj_dalloc( ct );
-        return NULL;
+        return nullptr;
     }
     
     /* trim white space and newlines off id */
@@ -137,7 +137,7 @@ struct CTABLE *nad_ctable_init( projCtx ctx, PAFile fid )
             break;
     }
 
-    ct->cvs = NULL;
+    ct->cvs = nullptr;
 
     return ct;
 }
@@ -158,13 +158,13 @@ int nad_ctable2_load( projCtx ctx, struct CTABLE *ct, PAFile fid )
     /* read all the actual shift values */
     a_size = ct->lim.lam * ct->lim.phi;
     ct->cvs = (FLP *) pj_malloc(sizeof(FLP) * a_size);
-    if( ct->cvs == NULL 
+    if( ct->cvs == nullptr 
         || pj_ctx_fread(ctx, ct->cvs, sizeof(FLP), a_size, fid) != a_size )
     {
         pj_dalloc( ct->cvs );
-        ct->cvs = NULL;
+        ct->cvs = nullptr;
 
-        if( getenv("PROJ_DEBUG") != NULL )
+        if( getenv("PROJ_DEBUG") != nullptr )
         {
             fprintf( stderr,
             "ctable2 loading failed on fread() - binary incompatible?\n" );
@@ -197,7 +197,7 @@ struct CTABLE *nad_ctable2_init( projCtx ctx, PAFile fid )
     if( pj_ctx_fread( ctx, header, sizeof(header), 1, fid ) != 1 )
     {
         pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-        return NULL;
+        return nullptr;
     }
 
     if( !IS_LSB )
@@ -210,15 +210,15 @@ struct CTABLE *nad_ctable2_init( projCtx ctx, PAFile fid )
     {
         pj_log( ctx, PJ_LOG_ERROR, "ctable2 - wrong header!" );
         pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
-        return NULL;
+        return nullptr;
     }
 
     /* read the table header */
     ct = (struct CTABLE *) pj_malloc(sizeof(struct CTABLE));
-    if( ct == NULL )
+    if( ct == nullptr )
     {
         pj_ctx_set_errno( ctx, ENOMEM );
-        return NULL;
+        return nullptr;
     }
 
     memcpy( ct->id,       header +  16, 80 );
@@ -235,7 +235,7 @@ struct CTABLE *nad_ctable2_init( projCtx ctx, PAFile fid )
     {
         pj_ctx_set_errno( ctx, PJD_ERR_FAILED_TO_LOAD_GRID );
         pj_dalloc( ct );
-        return NULL;
+        return nullptr;
     }
     
     /* trim white space and newlines off id */
@@ -247,7 +247,7 @@ struct CTABLE *nad_ctable2_init( projCtx ctx, PAFile fid )
             break;
     }
 
-    ct->cvs = NULL;
+    ct->cvs = nullptr;
 
     return ct;
 }
@@ -271,16 +271,16 @@ struct CTABLE *nad_init(projCtx ctx, char *name)
 /* -------------------------------------------------------------------- */
     strcpy(fname, name);
     if (!(fid = pj_open_lib(ctx, fname, "rb"))) {
-        return 0;
+        return nullptr;
     }
 
     ct = nad_ctable_init( ctx, fid );
-    if( ct != NULL )
+    if( ct != nullptr )
     {
         if( !nad_ctable_load( ctx, ct, fid ) )
         {
             nad_free( ct );
-            ct = NULL;
+            ct = nullptr;
         }
     }
 
@@ -297,7 +297,7 @@ struct CTABLE *nad_init(projCtx ctx, char *name)
 void nad_free(struct CTABLE *ct) 
 {
     if (ct) {
-        if( ct->cvs != NULL )
+        if( ct->cvs != nullptr )
             pj_dalloc(ct->cvs);
 
         pj_dalloc(ct);
diff --git a/src/nad_intr.c b/src/nad_intr.cpp
index 1f9d1e0c..1f9d1e0c 100644
--- a/src/nad_intr.c
+++ b/src/nad_intr.cpp
diff --git a/src/pj_open_lib.c b/src/open_lib.cpp
index 6b908360..c75b4af6 100644
--- a/src/pj_open_lib.c
+++ b/src/open_lib.cpp
@@ -39,14 +39,14 @@
 #include "proj_internal.h"
 #include "projects.h"
 
-static const char *(*pj_finder)(const char *) = NULL;
+static const char *(*pj_finder)(const char *) = nullptr;
 static int path_count = 0;
-static char **search_path = NULL;
+static char **search_path = nullptr;
 static const char * proj_lib_name =
 #ifdef PROJ_LIB
 PROJ_LIB;
 #else
-0;
+nullptr;
 #endif
 
 /************************************************************************/
@@ -71,7 +71,7 @@ void pj_set_searchpath ( int count, const char **path )
 {
     int i;
 
-    if (path_count > 0 && search_path != NULL)
+    if (path_count > 0 && search_path != nullptr)
     {
         for (i = 0; i < path_count; i++)
         {
@@ -79,15 +79,15 @@ void pj_set_searchpath ( int count, const char **path )
         }
         pj_dalloc(search_path);
         path_count = 0;
-        search_path = NULL;
+        search_path = nullptr;
     }
 
     if( count > 0 )
     {
-        search_path = pj_malloc(sizeof *search_path * count);
+        search_path = static_cast<char**>(pj_malloc(sizeof *search_path * count));
         for (i = 0; i < count; i++)
         {
-            search_path[i] = pj_malloc(strlen(path[i]) + 1);
+            search_path[i] = static_cast<char*>(pj_malloc(strlen(path[i]) + 1));
             strcpy(search_path[i], path[i]);
         }
     }
@@ -122,15 +122,15 @@ pj_open_lib_ex(projCtx ctx, const char *name, const char *mode,
     static const char dir_chars[] = "/";
 #endif
 
-    if( out_full_filename != NULL && out_full_filename_size > 0 )
+    if( out_full_filename != nullptr && out_full_filename_size > 0 )
         out_full_filename[0] = '\0';
 
     /* check if ~/name */
     if (*name == '~' && strchr(dir_chars,name[1]) )
-        if ((sysname = getenv("HOME")) != NULL) {
+        if ((sysname = getenv("HOME")) != nullptr) {
             if( strlen(sysname) + 1 + strlen(name) + 1 > sizeof(fname) )
             {
-                return NULL;
+                return nullptr;
             }
             (void)strcpy(fname, sysname);
             fname[n = (int)strlen(fname)] = DIR_CHAR;
@@ -138,7 +138,7 @@ pj_open_lib_ex(projCtx ctx, const char *name, const char *mode,
             (void)strcpy(fname+n, name + 1);
             sysname = fname;
         } else
-            return NULL;
+            return nullptr;
 
     /* or fixed path: /name, ./name or ../name */
     else if (strchr(dir_chars,*name)
@@ -148,14 +148,14 @@ pj_open_lib_ex(projCtx ctx, const char *name, const char *mode,
         sysname = name;
 
     /* or try to use application provided file finder */
-    else if( pj_finder != NULL && pj_finder( name ) != NULL )
+    else if( pj_finder != nullptr && pj_finder( name ) != nullptr )
         sysname = pj_finder( name );
 
     /* or is environment PROJ_LIB defined */
     else if ((sysname = getenv("PROJ_LIB")) || (sysname = proj_lib_name)) {
         if( strlen(sysname) + 1 + strlen(name) + 1 > sizeof(fname) )
         {
-            return NULL;
+            return nullptr;
         }
         (void)strcpy(fname, sysname);
         fname[n = (int)strlen(fname)] = DIR_CHAR;
@@ -165,9 +165,9 @@ pj_open_lib_ex(projCtx ctx, const char *name, const char *mode,
     } else /* just try it bare bones */
         sysname = name;
 
-    if ((fid = pj_ctx_fopen(ctx, sysname, mode)) != NULL)
+    if ((fid = pj_ctx_fopen(ctx, sysname, mode)) != nullptr)
     {
-        if( out_full_filename != NULL && out_full_filename_size > 0 )
+        if( out_full_filename != nullptr && out_full_filename_size > 0 )
         {
             strncpy(out_full_filename, sysname, out_full_filename_size);
             out_full_filename[out_full_filename_size-1] = '\0';
@@ -178,7 +178,7 @@ pj_open_lib_ex(projCtx ctx, const char *name, const char *mode,
     /* If none of those work and we have a search path, try it */
     if (!fid && path_count > 0)
     {
-        for (i = 0; fid == NULL && i < path_count; i++)
+        for (i = 0; fid == nullptr && i < path_count; i++)
         {
             if( strlen(search_path[i]) + 1 + strlen(name) + 1 <= sizeof(fname) )
             {
@@ -189,7 +189,7 @@ pj_open_lib_ex(projCtx ctx, const char *name, const char *mode,
         }
         if (fid)
         {
-            if( out_full_filename != NULL && out_full_filename_size > 0 )
+            if( out_full_filename != nullptr && out_full_filename_size > 0 )
             {
                 strncpy(out_full_filename, sysname, out_full_filename_size);
                 out_full_filename[out_full_filename_size-1] = '\0';
@@ -204,7 +204,7 @@ pj_open_lib_ex(projCtx ctx, const char *name, const char *mode,
     pj_log( ctx, PJ_LOG_DEBUG_MAJOR, 
             "pj_open_lib(%s): call fopen(%s) - %s",
             name, sysname,
-            fid == NULL ? "failed" : "succeeded" );
+            fid == nullptr ? "failed" : "succeeded" );
 
     return(fid);
 }
@@ -215,7 +215,7 @@ pj_open_lib_ex(projCtx ctx, const char *name, const char *mode,
 
 PAFile
 pj_open_lib(projCtx ctx, const char *name, const char *mode) {
-    return pj_open_lib_ex(ctx, name, mode, NULL, 0);
+    return pj_open_lib_ex(ctx, name, mode, nullptr, 0);
 }
 
 /************************************************************************/
@@ -238,7 +238,7 @@ int pj_find_file(projCtx ctx, const char *short_filename,
 {
     PAFile f = pj_open_lib_ex(ctx, short_filename, "rb", out_full_filename,
                               out_full_filename_size);
-    if( f != NULL )
+    if( f != nullptr )
     {
         pj_ctx_fclose(ctx, f);
         return 1;
diff --git a/src/pj_param.c b/src/param.cpp
index 4078dc83..74247b72 100644
--- a/src/pj_param.c
+++ b/src/param.cpp
@@ -12,9 +12,9 @@
 paralist *pj_mkparam(const char *str) {
     paralist *newitem;
 
-    if((newitem = (paralist *)pj_malloc(sizeof(paralist) + strlen(str))) != NULL) {
+    if((newitem = (paralist *)pj_malloc(sizeof(paralist) + strlen(str))) != nullptr) {
         newitem->used = 0;
-        newitem->next = 0;
+        newitem->next = nullptr;
         if (*str == '+')
             ++str;
         (void)strcpy(newitem->param, str);
@@ -28,8 +28,8 @@ paralist *pj_mkparam_ws (const char *str) {
     paralist *newitem;
     size_t len = 0;
 
-    if (0==str)
-        return 0;
+    if (nullptr==str)
+        return nullptr;
 
     /* Find start and length of string */
     while (isspace (*str))
@@ -43,12 +43,12 @@ paralist *pj_mkparam_ws (const char *str) {
 
     /* Use calloc to automagically 0-terminate the copy */
     newitem = (paralist *) pj_calloc (1, sizeof(paralist) + len + 1);
-    if (0==newitem)
-        return 0;
+    if (nullptr==newitem)
+        return nullptr;
     memmove(newitem->param, str, len);
 
     newitem->used = 0;
-    newitem->next = 0;
+    newitem->next = nullptr;
 
     return newitem;
 }
@@ -70,12 +70,12 @@ paralist *pj_param_exists (paralist *list, const char *parameter) {
     the t (for compile time known names, this is obviously not an issue).
 ***************************************************************************************/
     paralist *next = list;
-    char *c = strchr (parameter, '=');
+    const char *c = strchr (parameter, '=');
     size_t len = strlen (parameter);
     if (c)
         len = c - parameter;
-    if (list==0)
-        return 0;
+    if (list==nullptr)
+        return nullptr;
 
     for (next = list; next; next = next->next) {
         if (0==strncmp (parameter, next->param, len) && (next->param[len]=='=' || next->param[len]==0)) {
@@ -83,10 +83,10 @@ paralist *pj_param_exists (paralist *list, const char *parameter) {
             return next;
         }
         if (0==strcmp (parameter, "step"))
-            return 0;
+            return nullptr;
     }
 
-    return 0;
+    return nullptr;
 }
 
 
@@ -116,24 +116,24 @@ PROJVALUE pj_param (projCtx ctx, paralist *pl, const char *opt) {
     unsigned l;
     PROJVALUE value = {0};
 
-    if ( ctx == NULL )
+    if ( ctx == nullptr )
         ctx = pj_get_default_ctx();
 
     type = *opt++;
 
-    if (0==strchr ("tbirds", type)) {
+    if (nullptr==strchr ("tbirds", type)) {
         fprintf(stderr, "invalid request to pj_param, fatal\n");
         exit(1);
     }
 
     pl = pj_param_exists (pl, opt);
     if (type == 't') {
-        value.i = pl != 0;
+        value.i = pl != nullptr;
         return value;
     }
 
     /* Not found */
-    if (0==pl) {
+    if (nullptr==pl) {
         /* Return value after the switch, so that the return path is */
         /* taken in all cases */
         switch (type) {
@@ -144,7 +144,7 @@ PROJVALUE pj_param (projCtx ctx, paralist *pl, const char *opt) {
             value.f = 0.;
             break;
         case 's':
-            value.s = 0;
+            value.s = nullptr;
             break;
         }
         return value;
@@ -165,7 +165,7 @@ PROJVALUE pj_param (projCtx ctx, paralist *pl, const char *opt) {
         value.f = pj_atof(opt);
         break;
     case 'r':    /* degrees input */
-        value.f = dmstor_ctx(ctx, opt, 0);
+        value.f = dmstor_ctx(ctx, opt, nullptr);
         break;
     case 's':    /* char string */
         value.s = (char *) opt;
diff --git a/src/pj_phi2.c b/src/phi2.cpp
index a83302e6..a83302e6 100644
--- a/src/pj_phi2.c
+++ b/src/phi2.cpp
diff --git a/src/PJ_pipeline.c b/src/pipeline.cpp
index 618d4688..76fc58a5 100644
--- a/src/PJ_pipeline.c
+++ b/src/pipeline.cpp
@@ -109,12 +109,14 @@ Thomas Knudsen, thokn@sdfe.dk, 2016-05-20
 PROJ_HEAD(pipeline,         "Transformation pipeline manager");
 
 /* Projection specific elements for the PJ object */
+namespace { // anonymous namespace
 struct pj_opaque {
     int steps;
     char **argv;
     char **current_argv;
     PJ **pipeline;
 };
+} // anonymous namespace
 
 
 
@@ -132,10 +134,10 @@ static PJ_COORD pipeline_forward_4d (PJ_COORD point, PJ *P) {
     int i, first_step, last_step;
 
     first_step = 1;
-    last_step  = P->opaque->steps + 1;
+    last_step  = static_cast<struct pj_opaque*>(P->opaque)->steps + 1;
 
     for (i = first_step;  i != last_step;  i++)
-        point = proj_trans (P->opaque->pipeline[i], 1, point);
+        point = proj_trans (static_cast<struct pj_opaque*>(P->opaque)->pipeline[i], PJ_FWD, point);
 
     return point;
 }
@@ -144,11 +146,11 @@ static PJ_COORD pipeline_forward_4d (PJ_COORD point, PJ *P) {
 static PJ_COORD pipeline_reverse_4d (PJ_COORD point, PJ *P) {
     int i, first_step, last_step;
 
-    first_step = P->opaque->steps;
+    first_step = static_cast<struct pj_opaque*>(P->opaque)->steps;
     last_step  =  0;
 
     for (i = first_step;  i != last_step;  i--)
-        point = proj_trans (P->opaque->pipeline[i], -1, point);
+        point = proj_trans (static_cast<struct pj_opaque*>(P->opaque)->pipeline[i], PJ_INV, point);
 
     return point;
 }
@@ -161,8 +163,8 @@ static XYZ pipeline_forward_3d (LPZ lpz, PJ *P) {
     int i;
     point.lpz = lpz;
 
-    for (i = 1;  i <= P->opaque->steps;  i++)
-        point = pj_approx_3D_trans (P->opaque->pipeline[i], 1, point);
+    for (i = 1;  i <= static_cast<struct pj_opaque*>(P->opaque)->steps;  i++)
+        point = pj_approx_3D_trans (static_cast<struct pj_opaque*>(P->opaque)->pipeline[i], PJ_FWD, point);
 
     return point.xyz;
 }
@@ -173,8 +175,8 @@ static LPZ pipeline_reverse_3d (XYZ xyz, PJ *P) {
     int i;
     point.xyz = xyz;
 
-    for (i = P->opaque->steps;  i > 0 ;  i--)
-        point = pj_approx_3D_trans (P->opaque->pipeline[i], -1, point);
+    for (i = static_cast<struct pj_opaque*>(P->opaque)->steps;  i > 0 ;  i--)
+        point = pj_approx_3D_trans (static_cast<struct pj_opaque*>(P->opaque)->pipeline[i], PJ_INV, point);
 
     return point.lpz;
 }
@@ -187,8 +189,8 @@ static XY pipeline_forward (LP lp, PJ *P) {
     int i;
     point.lp = lp;
 
-    for (i = 1;  i <= P->opaque->steps;  i++)
-        point = pj_approx_2D_trans (P->opaque->pipeline[i], 1, point);
+    for (i = 1;  i <= static_cast<struct pj_opaque*>(P->opaque)->steps;  i++)
+        point = pj_approx_2D_trans (static_cast<struct pj_opaque*>(P->opaque)->pipeline[i], PJ_FWD, point);
 
     return point.xy;
 }
@@ -198,8 +200,8 @@ static LP pipeline_reverse (XY xy, PJ *P) {
     PJ_COORD point = {{0,0,0,0}};
     int i;
     point.xy = xy;
-    for (i = P->opaque->steps;  i > 0 ;  i--)
-        point = pj_approx_2D_trans (P->opaque->pipeline[i], -1, point);
+    for (i = static_cast<struct pj_opaque*>(P->opaque)->steps;  i > 0 ;  i--)
+        point = pj_approx_2D_trans (static_cast<struct pj_opaque*>(P->opaque)->pipeline[i], PJ_INV, point);
 
     return point.lp;
 }
@@ -207,22 +209,22 @@ static LP pipeline_reverse (XY xy, PJ *P) {
 
 
 
-static void *destructor (PJ *P, int errlev) {
+static PJ *destructor (PJ *P, int errlev) {
     int i;
-    if (0==P)
-        return 0;
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
     /* Deallocate each pipeine step, then pipeline array */
-    if (0!=P->opaque->pipeline)
-        for (i = 0;  i < P->opaque->steps; i++)
-            proj_destroy (P->opaque->pipeline[i+1]);
-    pj_dealloc (P->opaque->pipeline);
+    if (nullptr!=static_cast<struct pj_opaque*>(P->opaque)->pipeline)
+        for (i = 0;  i < static_cast<struct pj_opaque*>(P->opaque)->steps; i++)
+            proj_destroy (static_cast<struct pj_opaque*>(P->opaque)->pipeline[i+1]);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->pipeline);
 
-    pj_dealloc (P->opaque->argv);
-    pj_dealloc (P->opaque->current_argv);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->argv);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->current_argv);
 
     return pj_default_destructor(P, errlev);
 }
@@ -231,11 +233,11 @@ static void *destructor (PJ *P, int errlev) {
 static PJ *pj_create_pipeline (PJ *P, size_t steps) {
 
     /* Room for the pipeline: An array of PJ * with room for sentinels at both ends */
-    P->opaque->pipeline = pj_calloc (steps + 2, sizeof(PJ *));
-    if (0==P->opaque->pipeline)
-        return 0;
+    static_cast<struct pj_opaque*>(P->opaque)->pipeline = static_cast<PJ**>(pj_calloc (steps + 2, sizeof(PJ *)));
+    if (nullptr==static_cast<struct pj_opaque*>(P->opaque)->pipeline)
+        return nullptr;
 
-    P->opaque->steps = (int)steps;
+    static_cast<struct pj_opaque*>(P->opaque)->steps = (int)steps;
 
     return P;
 }
@@ -246,7 +248,7 @@ static PJ *pj_create_pipeline (PJ *P, size_t steps) {
 /* count the number of args in pipeline definition, and mark all args as used */
 static size_t argc_params (paralist *params) {
     size_t argc = 0;
-    for (; params != 0; params = params->next) {
+    for (; params != nullptr; params = params->next) {
         argc++;
         params->used = 1;
     }
@@ -254,18 +256,18 @@ static size_t argc_params (paralist *params) {
 }
 
 /* Sentinel for argument list */
-static char *argv_sentinel = "step";
+static const char *argv_sentinel = "step";
 
 /* turn paralist into argc/argv style argument list */
 static char **argv_params (paralist *params, size_t argc) {
     char **argv;
     size_t i = 0;
-    argv = pj_calloc (argc, sizeof (char *));
-    if (0==argv)
-        return 0;
-    for (; params != 0; params = params->next)
+    argv = static_cast<char**>(pj_calloc (argc, sizeof (char *)));
+    if (nullptr==argv)
+        return nullptr;
+    for (; params != nullptr; params = params->next)
         argv[i++] = params->param;
-    argv[i++] = argv_sentinel;
+    argv[i++] = const_cast<char*>(argv_sentinel);
     return argv;
 }
 
@@ -288,13 +290,13 @@ static void set_ellipsoid(PJ *P) {
     int err = proj_errno_reset (P);
 
     /* Break the linked list after the global args */
-    attachment = 0;
-    for (cur = P->params; cur != 0; cur = cur->next)
+    attachment = nullptr;
+    for (cur = P->params; cur != nullptr; cur = cur->next)
         /* cur->next will always be non 0 given argv_sentinel presence, */
         /* but this is far from being obvious for a static analyzer */
-        if (cur->next != 0 && strcmp(argv_sentinel, cur->next->param) == 0) {
+        if (cur->next != nullptr && strcmp(argv_sentinel, cur->next->param) == 0) {
             attachment = cur->next;
-            cur->next = 0;
+            cur->next = nullptr;
             break;
         }
 
@@ -320,7 +322,7 @@ static void set_ellipsoid(PJ *P) {
     /* Re-attach the dangling list */
     /* Note: cur will always be non 0 given argv_sentinel presence, */
     /* but this is far from being obvious for a static analyzer */
-    if( cur != 0 )
+    if( cur != nullptr )
         cur->next = attachment;
     proj_errno_restore (P, err);
 }
@@ -350,17 +352,17 @@ PJ *OPERATION(pipeline,0) {
     P->skip_inv_finalize = 1;
 
 
-    P->opaque = pj_calloc (1, sizeof(struct pj_opaque));
-    if (0==P->opaque)
+    P->opaque = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof(struct pj_opaque)));
+    if (nullptr==P->opaque)
         return destructor(P, ENOMEM);
 
     argc = (int)argc_params (P->params);
-    P->opaque->argv = argv = argv_params (P->params, argc);
-    if (0==argv)
+    static_cast<struct pj_opaque*>(P->opaque)->argv = argv = argv_params (P->params, argc);
+    if (nullptr==argv)
         return destructor (P, ENOMEM);
 
-    P->opaque->current_argv = current_argv = pj_calloc (argc, sizeof (char *));
-    if (0==current_argv)
+    static_cast<struct pj_opaque*>(P->opaque)->current_argv = current_argv = static_cast<char**>(pj_calloc (argc, sizeof (char *)));
+    if (nullptr==current_argv)
         return destructor (P, ENOMEM);
 
     /* Do some syntactical sanity checking */
@@ -385,7 +387,7 @@ PJ *OPERATION(pipeline,0) {
         }
     }
     nsteps--; /* Last instance of +step is just a sentinel */
-    P->opaque->steps = nsteps;
+    static_cast<struct pj_opaque*>(P->opaque)->steps = nsteps;
 
     if (-1==i_pipeline)
         return destructor (P, PJD_ERR_MALFORMED_PIPELINE); /* ERROR: no pipeline def */
@@ -394,7 +396,7 @@ PJ *OPERATION(pipeline,0) {
         return destructor (P, PJD_ERR_MALFORMED_PIPELINE); /* ERROR: no pipeline def */
 
     /* Make room for the pipeline and execution indicators */
-    if (0==pj_create_pipeline (P, nsteps))
+    if (nullptr==pj_create_pipeline (P, nsteps))
         return destructor (P, ENOMEM);
 
     set_ellipsoid(P);
@@ -405,7 +407,7 @@ PJ *OPERATION(pipeline,0) {
         int j;
         int  current_argc = 0;
         int  err;
-        PJ     *next_step = 0;
+        PJ     *next_step = nullptr;
 
         /* Build a set of setup args for the current step */
         proj_log_trace (P, "Pipeline: Building arg list for step no. %d", i);
@@ -429,7 +431,7 @@ PJ *OPERATION(pipeline,0) {
         next_step = proj_create_argv (P->ctx, current_argc, current_argv);
         proj_log_trace (P, "Pipeline: Step %d (%s) at %p", i, current_argv[0], next_step);
 
-        if (0==next_step) {
+        if (nullptr==next_step) {
             /* The step init failed, but possibly without setting errno. If so, we say "malformed" */
             int err_to_report = proj_errno(P);
             if (0==err_to_report)
@@ -447,14 +449,14 @@ PJ *OPERATION(pipeline,0) {
                 next_step->inverted = next_step->inverted == 0 ? 1 : 0;
             }
 
-        P->opaque->pipeline[i+1] = next_step;
+        static_cast<struct pj_opaque*>(P->opaque)->pipeline[i+1] = next_step;
 
         proj_log_trace (P, "Pipeline at [%p]:    step at [%p] (%s) done", P, next_step, current_argv[0]);
     }
 
     /* Require a forward path through the pipeline */
     for (i = 1; i <= nsteps; i++) {
-        PJ *Q = P->opaque->pipeline[i];
+        PJ *Q = static_cast<struct pj_opaque*>(P->opaque)->pipeline[i];
         if ( ( Q->inverted && (Q->inv || Q->inv3d || Q->fwd4d) ) ||
              (!Q->inverted && (Q->fwd || Q->fwd3d || Q->fwd4d) ) ) {
             continue;
@@ -466,21 +468,21 @@ PJ *OPERATION(pipeline,0) {
 
     /* determine if an inverse operation is possible */
     for (i = 1; i <= nsteps; i++) {
-        PJ *Q = P->opaque->pipeline[i];
+        PJ *Q = static_cast<struct pj_opaque*>(P->opaque)->pipeline[i];
         if ( pj_has_inverse(Q) ) {
             continue;
         } else {
-            P->inv   = 0;
-            P->inv3d = 0;
-            P->inv4d = 0;
+            P->inv   = nullptr;
+            P->inv3d = nullptr;
+            P->inv4d = nullptr;
             break;
         }
     }
 
     /* Check that output units from step i are compatible with expected units in step i+1 */
     for (i = 1; i < nsteps; i++) {
-        enum pj_io_units unit_returned = pj_right (P->opaque->pipeline[i]);
-        enum pj_io_units unit_expected = pj_left  (P->opaque->pipeline[i+1]);
+        enum pj_io_units unit_returned = pj_right (static_cast<struct pj_opaque*>(P->opaque)->pipeline[i]);
+        enum pj_io_units unit_expected = pj_left  (static_cast<struct pj_opaque*>(P->opaque)->pipeline[i+1]);
 
         if ( unit_returned == PJ_IO_UNITS_WHATEVER || unit_expected == PJ_IO_UNITS_WHATEVER )
             continue;
@@ -493,9 +495,9 @@ PJ *OPERATION(pipeline,0) {
     proj_log_trace (P, "Pipeline: %d steps built. Determining i/o characteristics", nsteps);
 
     /* Determine forward input (= reverse output) data type */
-    P->left = pj_left (P->opaque->pipeline[1]);
+    P->left = pj_left (static_cast<struct pj_opaque*>(P->opaque)->pipeline[1]);
 
     /* Now, correspondingly determine forward output (= reverse input) data type */
-    P->right = pj_right (P->opaque->pipeline[nsteps]);
+    P->right = pj_right (static_cast<struct pj_opaque*>(P->opaque)->pipeline[nsteps]);
     return P;
 }
diff --git a/src/pj_internal.c b/src/pj_internal.c
deleted file mode 100644
index 7eb917be..00000000
--- a/src/pj_internal.c
+++ /dev/null
@@ -1,445 +0,0 @@
-/******************************************************************************
- * Project:  PROJ.4
- * Purpose:  This is primarily material originating from pj_obs_api.c
- *           (now proj_4D_api.c), that does not fit into the API
- *           category. Hence this pile of tubings and fittings for
- *           PROJ.4 internal plumbing.
- *
- * Author:   Thomas Knudsen,  thokn@sdfe.dk,  2017-07-05
- *
- ******************************************************************************
- * Copyright (c) 2016, 2017, 2018, Thomas Knudsen/SDFE
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included
- * in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
- * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *****************************************************************************/
-
-#include <ctype.h>
-#include <errno.h>
-#include <math.h>
-#include <stdarg.h>
-#include <stddef.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "geodesic.h"
-#include "proj_internal.h"
-#include "projects.h"
-
-
-enum pj_io_units pj_left (PJ *P) {
-    enum pj_io_units u = P->inverted? P->right: P->left;
-    if (u==PJ_IO_UNITS_CLASSIC)
-        return PJ_IO_UNITS_PROJECTED;
-    return u;
-}
-
-enum pj_io_units pj_right (PJ *P) {
-    enum pj_io_units u = P->inverted? P->left: P->right;
-    if (u==PJ_IO_UNITS_CLASSIC)
-        return PJ_IO_UNITS_PROJECTED;
-    return u;
-}
-
-
-/* Work around non-constness of MSVC HUGE_VAL by providing functions rather than constants */
-PJ_COORD proj_coord_error (void) {
-    PJ_COORD c;
-    c.v[0] = c.v[1] = c.v[2] = c.v[3] = HUGE_VAL;
-    return c;
-}
-
-
-
-/**************************************************************************************/
-PJ_COORD pj_approx_2D_trans (PJ *P, PJ_DIRECTION direction, PJ_COORD coo) {
-/***************************************************************************************
-Behave mostly as proj_trans, but attempt to use 2D interfaces only.
-Used in gie.c, to enforce testing 2D code, and by PJ_pipeline.c to implement
-chained calls starting out with a call to its 2D interface.
-***************************************************************************************/
-    if (0==P)
-        return coo;
-    if (P->inverted)
-        direction = -direction;
-    switch (direction) {
-        case PJ_FWD:
-            coo.xy = pj_fwd (coo.lp, P);
-            return coo;
-        case PJ_INV:
-            coo.lp = pj_inv (coo.xy, P);
-            return coo;
-        case PJ_IDENT:
-            return coo;
-        default:
-            break;
-    }
-    proj_errno_set (P, EINVAL);
-    return proj_coord_error ();
-}
-
-
-/**************************************************************************************/
-PJ_COORD pj_approx_3D_trans (PJ *P, PJ_DIRECTION direction, PJ_COORD coo) {
-/***************************************************************************************
-Companion to pj_approx_2D_trans.
-
-Behave mostly as proj_trans, but attempt to use 3D interfaces only.
-Used in gie.c, to enforce testing 3D code, and by PJ_pipeline.c to implement
-chained calls starting out with a call to its 3D interface.
-***************************************************************************************/
-    if (0==P)
-        return coo;
-    if (P->inverted)
-        direction = -direction;
-    switch (direction) {
-        case PJ_FWD:
-            coo.xyz = pj_fwd3d (coo.lpz, P);
-            return coo;
-        case PJ_INV:
-            coo.lpz = pj_inv3d (coo.xyz, P);
-            return coo;
-        case PJ_IDENT:
-            return coo;
-        default:
-            break;
-    }
-    proj_errno_set (P, EINVAL);
-    return proj_coord_error ();
-}
-
-/**************************************************************************************/
-int pj_has_inverse(PJ *P) {
-/***************************************************************************************
-Check if a a PJ has an inverse.
-***************************************************************************************/
-    return ( (P->inverted && (P->fwd || P->fwd3d || P->fwd4d) ) ||
-             ( P->inv || P->inv3d || P->inv4d) );
-}
-
-
-/* Move P to a new context - or to the default context if 0 is specified */
-void proj_context_set (PJ *P, PJ_CONTEXT *ctx) {
-    if (0==ctx)
-        ctx = pj_get_default_ctx ();
-    pj_set_ctx (P, ctx);
-}
-
-
-void proj_context_inherit (PJ *parent, PJ *child) {
-    if (0==parent)
-        pj_set_ctx (child, pj_get_default_ctx());
-    else
-        pj_set_ctx (child, pj_get_ctx(parent));
-}
-
-
-
-/*****************************************************************************/
-char *pj_chomp (char *c) {
-/******************************************************************************
-Strip pre- and postfix whitespace. Inline comments (indicated by '#') are
-considered whitespace.
-******************************************************************************/
-    size_t i, n;
-    char *comment;
-    char *start = c;
-
-    if (0==c)
-        return 0;
-
-    comment = strchr (c, '#');
-    if (comment)
-        *comment = 0;
-
-    n = strlen (c);
-    if (0==n)
-        return c;
-
-    /* Eliminate postfix whitespace */
-    for (i = n - 1;  (i > 0) && (isspace (c[i]) || ';'==c[i]);  i--)
-        c[i] = 0;
-
-    /* Find start of non-whitespace */
-    while (0 != *start  &&  (';'==*start  ||  isspace (*start)))
-        start++;
-
-    n = strlen (start);
-    if (0==n) {
-        c[0] = 0;
-        return c;
-    }
-
-    memmove (c, start, n + 1);
-    return c;
-}
-
-
-
-/*****************************************************************************/
-char *pj_shrink (char *c) {
-/******************************************************************************
-Collapse repeated whitespace. Remove '+' and ';'. Make ',' and '=' greedy,
-consuming their surrounding whitespace.
-******************************************************************************/
-    size_t i, j, n;
-
-    /* Flag showing that a whitespace (ws) has been written after last non-ws */
-    size_t ws;
-
-    if (0==c)
-       return 0;
-
-    pj_chomp (c);
-    n = strlen (c);
-
-    /* First collapse repeated whitespace (including +/;) */
-    i = 0;
-    ws = 0;
-    for (j = 0;  j < n;  j++) {
-
-        /* Eliminate prefix '+', only if preceded by whitespace */
-        /* (i.e. keep it in 1.23e+08) */
-        if ((i > 0) && ('+'==c[j]) && ws)
-            c[j] = ' ';
-        if ((i==0) && ('+'==c[j]))
-            c[j] = ' ';
-
-        if (isspace (c[j]) || ';'==c[j]) {
-            if (0==ws && (i > 0))
-                c[i++] = ' ';
-            ws = 1;
-            continue;
-        }
-        else {
-            ws = 0;
-            c[i++] = c[j];
-        }
-    }
-    c[i] = 0;
-    n = strlen(c);
-
-    /* Then make ',' and '=' greedy */
-    i = 0;
-    for (j = 0;  j < n;  j++) {
-        if (i==0) {
-            c[i++] = c[j];
-            continue;
-        }
-
-        /* Skip space before '='/',' */
-        if ('='==c[j] || ','==c[j]) {
-            if (c[i - 1]==' ')
-               c[i - 1] = c[j];
-            else
-                c[i++] = c[j];
-            continue;
-        }
-
-        if (' '==c[j] && ('='==c[i - 1] || ','==c[i - 1]) )
-            continue;
-
-        c[i++] = c[j];
-    }
-    c[i] = 0;
-    return c;
-}
-
-
-
-/*****************************************************************************/
-size_t pj_trim_argc (char *args) {
-/******************************************************************************
-Trim all unnecessary whitespace (and non-essential syntactic tokens) from the
-argument string, args, and count its number of elements.
-******************************************************************************/
-    size_t i, m, n;
-    pj_shrink (args);
-    n = strlen (args);
-    if (n==0)
-        return 0;
-    for (i = m = 0;  i < n;  i++) {
-        if (' '==args[i]) {
-            args[i] = 0;
-            m++;
-        }
-    }
-    return m + 1;
-}
-
-
-
-/*****************************************************************************/
-char **pj_trim_argv (size_t argc, char *args) {
-/******************************************************************************
-Create an argv-style array from elements placed in the argument string, args.
-
-args is a trimmed string as returned by pj_trim_argc(), and argc is the number
-of trimmed strings found (i.e. the return value of pj_trim_args()). Hence,
-    int argc    = pj_trim_argc (args);
-    char **argv = pj_trim_argv (argc, args);
-will produce a classic style (argc, argv) pair from a string of whitespace
-separated args. No new memory is allocated for storing the individual args
-(they stay in the args string), but for the pointers to the args a new array
-is allocated and returned.
-
-It is the duty of the caller to free this array.
-******************************************************************************/
-    size_t i, j;
-    char **argv;
-
-    if (0==args)
-        return 0;
-    if (0==argc)
-        return 0;
-
-
-    /* turn the input string into an array of strings */
-    argv = (char **) calloc (argc, sizeof (char *));
-    if (0==argv)
-        return 0;
-    argv[0] = args;
-    j = 1;
-    for (i = 0;  ;  i++) {
-        if (0==args[i]) {
-            argv[j++] = args + (i + 1);
-        }
-        if (j==argc)
-            break;
-    }
-    return argv;
-}
-
-
-
-/*****************************************************************************/
-char *pj_make_args (size_t argc, char **argv) {
-/******************************************************************************
-pj_make_args is the inverse of the pj_trim_argc/pj_trim_argv combo: It
-converts free format command line input to something proj_create can consume.
-
-Allocates, and returns, an array of char, large enough to hold a whitespace
-separated copy of the args in argv. It is the duty of the caller to free this
-array.
-******************************************************************************/
-    size_t i, n;
-    char *p;
-
-    for (i = n = 0;  i < argc;  i++)
-        n += strlen (argv[i]);
-
-    p = pj_calloc (n + argc + 1, sizeof (char));
-    if (0==p)
-        return 0;
-    if (0==argc)
-        return p;
-
-    for (i = 0;  i < argc;  i++) {
-        strcat (p, argv[i]);
-        strcat (p, " ");
-    }
-    return pj_shrink (p);
-}
-
-
-
-/*****************************************************************************/
-void proj_context_errno_set (PJ_CONTEXT *ctx, int err) {
-/******************************************************************************
-Raise an error directly on a context, without going through a PJ belonging
-to that context.
-******************************************************************************/
-    if (0==ctx)
-        ctx = pj_get_default_ctx();
-    pj_ctx_set_errno (ctx, err);
-}
-
-/*  logging  */
-
-/* pj_vlog resides in pj_log.c and relates to pj_log as vsprintf relates to sprintf */
-void pj_vlog( projCtx ctx, int level, const char *fmt, va_list args );
-
-
-/***************************************************************************************/
-PJ_LOG_LEVEL proj_log_level (PJ_CONTEXT *ctx, PJ_LOG_LEVEL log_level) {
-/****************************************************************************************
-   Set logging level 0-3. Higher number means more debug info. 0 turns it off
-****************************************************************************************/
-    PJ_LOG_LEVEL previous;
-    if (0==ctx)
-        ctx = pj_get_default_ctx();
-    if (0==ctx)
-        return PJ_LOG_TELL;
-    previous = abs (ctx->debug_level);
-    if (PJ_LOG_TELL==log_level)
-        return previous;
-    ctx->debug_level = log_level;
-    return previous;
-}
-
-
-/*****************************************************************************/
-void proj_log_error (PJ *P, const char *fmt, ...) {
-/******************************************************************************
-   For reporting the most severe events.
-******************************************************************************/
-    va_list args;
-    va_start( args, fmt );
-    pj_vlog (pj_get_ctx (P), PJ_LOG_ERROR , fmt, args);
-    va_end( args );
-}
-
-
-/*****************************************************************************/
-void proj_log_debug (PJ *P, const char *fmt, ...) {
-/******************************************************************************
-   For reporting debugging information.
-******************************************************************************/
-    va_list args;
-    va_start( args, fmt );
-    pj_vlog (pj_get_ctx (P), PJ_LOG_DEBUG_MAJOR , fmt, args);
-    va_end( args );
-}
-
-
-/*****************************************************************************/
-void proj_log_trace (PJ *P, const char *fmt, ...) {
-/******************************************************************************
-   For reporting embarrasingly detailed debugging information.
-******************************************************************************/
-    va_list args;
-    va_start( args, fmt );
-    pj_vlog (pj_get_ctx (P), PJ_LOG_DEBUG_MINOR , fmt, args);
-    va_end( args );
-}
-
-
-/*****************************************************************************/
-void proj_log_func (PJ_CONTEXT *ctx, void *app_data, PJ_LOG_FUNCTION logf) {
-/******************************************************************************
-    Put a new logging function into P's context. The opaque object app_data is
-    passed as first arg at each call to the logger
-******************************************************************************/
-    if (0==ctx)
-        pj_get_default_ctx ();
-    if (0==ctx)
-        return;
-    ctx->app_data = app_data;
-    if (0!=logf)
-        ctx->logger = logf;
-}
diff --git a/src/pj_pr_list.c b/src/pr_list.cpp
index 4e71e471..b8ad2c04 100644
--- a/src/pj_pr_list.c
+++ b/src/pr_list.cpp
@@ -67,7 +67,7 @@ char *pj_get_def( PJ *P, int options )
 
     definition = (char *) pj_malloc(def_max);
     if (!definition)
-        return NULL;
+        return nullptr;
     definition[0] = '\0';
 
     for (t = P->params; t; t = t->next)
@@ -91,7 +91,7 @@ char *pj_get_def( PJ *P, int options )
             }
             else {
                 pj_dalloc( definition );
-                return NULL;
+                return nullptr;
             }
         }
 
diff --git a/src/proj.h b/src/proj.h
index 5c0e8fdc..8ec48088 100644
--- a/src/proj.h
+++ b/src/proj.h
@@ -331,7 +331,11 @@ typedef struct projCtx_t PJ_CONTEXT;
 
 
 /* Functionality for handling thread contexts */
+#ifdef __cplusplus
+#define PJ_DEFAULT_CTX nullptr
+#else
 #define PJ_DEFAULT_CTX 0
+#endif
 PJ_CONTEXT PROJ_DLL *proj_context_create (void);
 PJ_CONTEXT PROJ_DLL *proj_context_destroy (PJ_CONTEXT *ctx);
 
diff --git a/src/proj_mdist.c b/src/proj_mdist.cpp
index 777f704d..e3f0f5c6 100644
--- a/src/proj_mdist.c
+++ b/src/proj_mdist.cpp
@@ -37,12 +37,14 @@
 #define MAX_ITER 20
 #define TOL 1e-14
 
+namespace { // anonymous namespace
 struct MDIST {
 	int nb;
 	double es;
 	double E;
 	double b[1];
 };
+} // anonymous namespace
 	void *
 proj_mdist_ini(double es) {
 	double numf, numfi, twon1, denf, denfi, ens, T, twon;
@@ -71,8 +73,8 @@ proj_mdist_ini(double es) {
 		El = Es;
 	}
 	if ((b = (struct MDIST *)malloc(sizeof(struct MDIST)+
-		(i*sizeof(double)))) == NULL)
-		return(NULL);
+		(i*sizeof(double)))) == nullptr)
+		return(nullptr);
 	b->nb = i - 1;
 	b->es = es;
 	b->E = Es;
diff --git a/src/PJ_aea.c b/src/projections/aea.cpp
index 640f1013..c4a4a72a 100644
--- a/src/PJ_aea.c
+++ b/src/projections/aea.cpp
@@ -67,6 +67,7 @@ static double phi1_(double qs, double Te, double Tone_es) {
 }
 
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  ec;
     double  n;
@@ -80,16 +81,17 @@ struct pj_opaque {
     double  *en;
     int     ellips;
 };
+} // anonymous namespace
 
 
-static void *destructor (PJ *P, int errlev) {                        /* Destructor */
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {                        /* Destructor */
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->en);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
     return pj_default_destructor (P, errlev);
 }
 
@@ -99,7 +101,7 @@ static void *destructor (PJ *P, int errlev) {                        /* Destruct
 
 static XY e_forward (LP lp, PJ *P) {   /* Ellipsoid/spheroid, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     Q->rho = Q->c - (Q->ellips ? Q->n * pj_qsfn(sin(lp.phi), P->e, P->one_es) : Q->n2 * sin(lp.phi));;
     if (Q->rho < 0.) {
         proj_errno_set(P, PJD_ERR_TOLERANCE_CONDITION);
@@ -114,7 +116,7 @@ static XY e_forward (LP lp, PJ *P) {   /* Ellipsoid/spheroid, forward */
 
 static LP e_inverse (XY xy, PJ *P) {   /* Ellipsoid/spheroid, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     if( (Q->rho = hypot(xy.x, xy.y = Q->rho0 - xy.y)) != 0.0 ) {
         if (Q->n < 0.) {
             Q->rho = -Q->rho;
@@ -148,7 +150,7 @@ static LP e_inverse (XY xy, PJ *P) {   /* Ellipsoid/spheroid, inverse */
 static PJ *setup(PJ *P) {
     double cosphi, sinphi;
     int secant;
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     P->inv = e_inverse;
     P->fwd = e_forward;
@@ -196,8 +198,8 @@ static PJ *setup(PJ *P) {
 
 
 PJ *PROJECTION(aea) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
@@ -209,8 +211,8 @@ PJ *PROJECTION(aea) {
 
 
 PJ *PROJECTION(leac) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
diff --git a/src/PJ_aeqd.c b/src/projections/aeqd.cpp
index 5d8c3d38..1a350d90 100644
--- a/src/PJ_aeqd.c
+++ b/src/projections/aeqd.cpp
@@ -32,13 +32,16 @@
 #include "projects.h"
 #include "proj_math.h"
 
+namespace { // anonymous namespace
 enum Mode {
     N_POLE = 0,
     S_POLE = 1,
     EQUIT  = 2,
     OBLIQ  = 3
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  sinph0;
     double  cosph0;
@@ -51,6 +54,7 @@ struct pj_opaque {
     enum Mode mode;
     struct geod_geodesic g;
 };
+} // anonymous namespace
 
 PROJ_HEAD(aeqd, "Azimuthal Equidistant") "\n\tAzi, Sph&Ell\n\tlat_0 guam";
 
@@ -58,14 +62,14 @@ PROJ_HEAD(aeqd, "Azimuthal Equidistant") "\n\tAzi, Sph&Ell\n\tlat_0 guam";
 #define TOL 1.e-14
 
 
-static void *destructor (PJ *P, int errlev) {                        /* Destructor */
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {                        /* Destructor */
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->en);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
     return pj_default_destructor (P, errlev);
 }
 
@@ -73,7 +77,7 @@ static void *destructor (PJ *P, int errlev) {                        /* Destruct
 
 static XY e_guam_fwd(LP lp, PJ *P) {        /* Guam elliptical */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  cosphi, sinphi, t;
 
     cosphi = cos(lp.phi);
@@ -89,7 +93,7 @@ static XY e_guam_fwd(LP lp, PJ *P) {        /* Guam elliptical */
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  coslam, cosphi, sinphi, rho;
     double azi1, azi2, s12;
     double lam1, phi1, lam2, phi2;
@@ -128,7 +132,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  coslam, cosphi, sinphi;
 
     sinphi = sin(lp.phi);
@@ -175,7 +179,7 @@ oblcon:
 
 static LP e_guam_inv(XY xy, PJ *P) { /* Guam elliptical */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double x2, t = 0.0;
     int i;
 
@@ -193,7 +197,7 @@ static LP e_guam_inv(XY xy, PJ *P) { /* Guam elliptical */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double c;
     double azi1, azi2, s12, x2, y2, lat1, lon1, lat2, lon2;
 
@@ -225,7 +229,7 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double cosc, c_rh, sinc;
 
     if ((c_rh = hypot(xy.x, xy.y)) > M_PI) {
@@ -265,8 +269,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(aeqd) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
diff --git a/src/PJ_airy.c b/src/projections/airy.cpp
index 75f95780..0eb5efd7 100644
--- a/src/PJ_airy.c
+++ b/src/projections/airy.cpp
@@ -34,13 +34,16 @@
 PROJ_HEAD(airy, "Airy") "\n\tMisc Sph, no inv\n\tno_cut lat_b=";
 
 
+namespace { // anonymous namespace
 enum Mode {
     N_POLE = 0,
     S_POLE = 1,
     EQUIT  = 2,
     OBLIQ  = 3
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  p_halfpi;
     double  sinph0;
@@ -49,6 +52,7 @@ struct pj_opaque {
     enum Mode mode;
     int     no_cut; /* do not cut at hemisphere limit */
 };
+} // anonymous namespace
 
 
 # define EPS 1.e-10
@@ -56,7 +60,7 @@ struct pj_opaque {
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  sinlam, coslam, cosphi, sinphi, t, s, Krho, cosz;
 
     sinlam = sin(lp.lam);
@@ -111,8 +115,8 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 PJ *PROJECTION(airy) {
     double beta;
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
 
     P->opaque = Q;
diff --git a/src/PJ_aitoff.c b/src/projections/aitoff.cpp
index 82c981d5..effd2c29 100644
--- a/src/PJ_aitoff.c
+++ b/src/projections/aitoff.cpp
@@ -37,15 +37,19 @@
 #include "projects.h"
 
 
+namespace { // anonymous namespace
 enum Mode {
     AITOFF = 0,
     WINKEL_TRIPEL = 1
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  cosphi1;
     enum Mode mode;
 };
+} // anonymous namespace
 
 
 PROJ_HEAD(aitoff, "Aitoff") "\n\tMisc Sph";
@@ -60,7 +64,7 @@ FORWARD(s_forward); /* spheroid */
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double c, d;
 
     if((d = acos(cos(lp.phi) * cos(c = 0.5 * lp.lam))) != 0.0) {/* basic Aitoff */
@@ -98,7 +102,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     int iter, MAXITER = 10, round = 0, MAXROUND = 20;
     double EPSILON = 1e-12, D, C, f1, f2, f1p, f1l, f2p, f2l, dp, dl, sl, sp, cp, cl, x, y;
 
@@ -170,8 +174,8 @@ static PJ *setup(PJ *P) {
 
 
 PJ *PROJECTION(aitoff) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
@@ -181,8 +185,8 @@ PJ *PROJECTION(aitoff) {
 
 
 PJ *PROJECTION(wintri) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_august.c b/src/projections/august.cpp
index e891e84e..b5a21ef7 100644
--- a/src/PJ_august.c
+++ b/src/projections/august.cpp
@@ -27,7 +27,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 
 PJ *PROJECTION(august) {
-    P->inv = 0;
+    P->inv = nullptr;
     P->fwd = s_forward;
     P->es = 0.;
     return P;
diff --git a/src/PJ_bacon.c b/src/projections/bacon.cpp
index f0f11c9d..6c6350fe 100644
--- a/src/PJ_bacon.c
+++ b/src/projections/bacon.cpp
@@ -7,10 +7,12 @@
 #include "projects.h"
 
 
+namespace { // anonymous namespace
 struct pj_opaque {
 	int bacn;
 	int ortl;
 };
+} // anonymous namespace
 
 PROJ_HEAD(apian, "Apian Globular I") "\n\tMisc Sph, no inv";
 PROJ_HEAD(ortel, "Ortelius Oval") "\n\tMisc Sph, no inv";
@@ -19,7 +21,7 @@ PROJ_HEAD(bacon, "Bacon Globular") "\n\tMisc Sph, no inv";
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 	double ax, f;
 
 	xy.y = Q->bacn ? M_HALFPI * sin(lp.phi) : lp.phi;
@@ -39,8 +41,8 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 
 PJ *PROJECTION(bacon) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -53,8 +55,8 @@ PJ *PROJECTION(bacon) {
 
 
 PJ *PROJECTION(apian) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -66,8 +68,8 @@ PJ *PROJECTION(apian) {
 
 
 PJ *PROJECTION(ortel) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_bertin1953.c b/src/projections/bertin1953.cpp
index 5a027da2..2203d6f1 100644
--- a/src/PJ_bertin1953.c
+++ b/src/projections/bertin1953.cpp
@@ -21,14 +21,16 @@
 PROJ_HEAD(bertin1953, "Bertin 1953")
     "\n\tMisc Sph no inv.";
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double cos_delta_phi, sin_delta_phi, cos_delta_gamma, sin_delta_gamma, deltaLambda;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     double fu = 1.4, k = 12., w = 1.68, d;
 
@@ -74,8 +76,8 @@ static XY s_forward (LP lp, PJ *P) {
 
 
 PJ *PROJECTION(bertin1953) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_bipc.c b/src/projections/bipc.cpp
index e4a69077..19a6bbe1 100644
--- a/src/PJ_bipc.c
+++ b/src/projections/bipc.cpp
@@ -29,14 +29,16 @@ PROJ_HEAD(bipc, "Bipolar conic of western hemisphere") "\n\tConic Sph";
 # define R104   1.81514242207410275904
 
 
+namespace { // anonymous namespace
 struct pj_opaque {
     int noskew;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double cphi, sphi, tphi, t, al, Az, z, Av, cdlam, sdlam, r;
     int tag;
 
@@ -113,7 +115,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double t, r, rp, rl, al, z = 0.0, fAz, Az, s, c, Av;
     int neg, i;
 
@@ -161,8 +163,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(bipc) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_boggs.c b/src/projections/boggs.cpp
index 119357c0..119357c0 100644
--- a/src/PJ_boggs.c
+++ b/src/projections/boggs.cpp
diff --git a/src/PJ_bonne.c b/src/projections/bonne.cpp
index d3d5b757..385c1c4b 100644
--- a/src/PJ_bonne.c
+++ b/src/projections/bonne.cpp
@@ -9,6 +9,7 @@ PROJ_HEAD(bonne, "Bonne (Werner lat_1=90)")
     "\n\tConic Sph&Ell\n\tlat_1=";
 #define EPS10   1e-10
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double phi1;
     double cphi1;
@@ -16,11 +17,12 @@ struct pj_opaque {
     double m1;
     double *en;
 };
+} // anonymous namespace
 
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double rh, E, c;
 
     rh = Q->am1 + Q->m1 - pj_mlfn(lp.phi, E = sin(lp.phi), c = cos(lp.phi), Q->en);
@@ -33,7 +35,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double E, rh;
 
     rh = Q->cphi1 + Q->phi1 - lp.phi;
@@ -48,7 +50,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double rh;
 
     rh = hypot(xy.x, xy.y = Q->cphi1 - xy.y);
@@ -67,7 +69,7 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double s, rh;
 
     rh = hypot(xy.x, xy.y = Q->am1 - xy.y);
@@ -87,22 +89,22 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 
 
 
-static void *destructor (PJ *P, int errlev) {                        /* Destructor */
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {                        /* Destructor */
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->en);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
     return pj_default_destructor (P, errlev);
 }
 
 
 PJ *PROJECTION(bonne) {
     double c;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
@@ -113,7 +115,7 @@ PJ *PROJECTION(bonne) {
 
     if (P->es != 0.0) {
         Q->en = pj_enfn(P->es);
-        if (0==Q->en)
+        if (nullptr==Q->en)
             return destructor(P, ENOMEM);
         Q->m1 = pj_mlfn(Q->phi1, Q->am1 = sin(Q->phi1),
             c = cos(Q->phi1), Q->en);
diff --git a/src/PJ_calcofi.c b/src/projections/calcofi.cpp
index ed4cfe86..e81e4d2a 100644
--- a/src/PJ_calcofi.c
+++ b/src/projections/calcofi.cpp
@@ -141,7 +141,7 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(calcofi) {
-    P->opaque = 0;
+    P->opaque = nullptr;
 
     /* if the user has specified +lon_0 or +k0 for some reason,
     we're going to ignore it so that xy is consistent with point O */
diff --git a/src/PJ_cass.c b/src/projections/cass.cpp
index 4e3b4251..c831558c 100644
--- a/src/PJ_cass.c
+++ b/src/projections/cass.cpp
@@ -15,17 +15,19 @@ PROJ_HEAD(cass, "Cassini") "\n\tCyl, Sph&Ell";
 # define C5 .06666666666666666666
 
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double *en;
     double m0;
 };
+} // anonymous namespace
 
 
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     double n, t, a1, c, a2, tn;
     XY xy = {0.0, 0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     xy.y = pj_mlfn (lp.phi, n = sin (lp.phi), c = cos (lp.phi), Q->en);
 
@@ -55,7 +57,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     double n, t, r, dd, d2, tn, ph1;
     LP lp = {0.0, 0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     ph1 = pj_inv_mlfn (P->ctx, Q->m0 + xy.y, P->es, Q->en);
     tn  = tan (ph1); t = tn*tn;
@@ -81,14 +83,14 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     return lp;
 }
 
-static void *destructor (PJ *P, int errlev) {                        /* Destructor */
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {                        /* Destructor */
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->en);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
     return pj_default_destructor (P, errlev);
 }
 
@@ -104,16 +106,16 @@ PJ *PROJECTION(cass) {
     }
 
     /* otherwise it's ellipsoidal */
-    P->opaque = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==P->opaque)
+    P->opaque = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, ENOMEM);
     P->destructor = destructor;
 
-    P->opaque->en = pj_enfn (P->es);
-    if (0==P->opaque->en)
+    static_cast<struct pj_opaque*>(P->opaque)->en = pj_enfn (P->es);
+    if (nullptr==static_cast<struct pj_opaque*>(P->opaque)->en)
         return pj_default_destructor (P, ENOMEM);
 
-    P->opaque->m0 = pj_mlfn (P->phi0,  sin (P->phi0),  cos (P->phi0),  P->opaque->en);
+    static_cast<struct pj_opaque*>(P->opaque)->m0 = pj_mlfn (P->phi0,  sin (P->phi0),  cos (P->phi0),  static_cast<struct pj_opaque*>(P->opaque)->en);
     P->inv = e_inverse;
     P->fwd = e_forward;
 
diff --git a/src/PJ_cc.c b/src/projections/cc.cpp
index 152e6e4a..152e6e4a 100644
--- a/src/PJ_cc.c
+++ b/src/projections/cc.cpp
diff --git a/src/PJ_ccon.c b/src/projections/ccon.cpp
index 0b8b70cb..4f7dedb4 100644
--- a/src/PJ_ccon.c
+++ b/src/projections/ccon.cpp
@@ -28,6 +28,7 @@
 
 #define EPS10   1e-10
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double phi1;
     double ctgphi1;
@@ -35,6 +36,7 @@ struct pj_opaque {
     double cosphi1;
     double *en;
 };
+} // anonymous namespace
 
 PROJ_HEAD(ccon, "Central Conic")
     "\n\tCentral Conic, Sph\n\tlat_1=";
@@ -43,7 +45,7 @@ PROJ_HEAD(ccon, "Central Conic")
 
 static XY forward (LP lp, PJ *P) {
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double r;
 
     r = Q->ctgphi1 - tan(lp.phi - Q->phi1);
@@ -56,7 +58,7 @@ static XY forward (LP lp, PJ *P) {
 
 static LP inverse (XY xy, PJ *P) {
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     xy.y = Q->ctgphi1 - xy.y;
     lp.phi = Q->phi1 - atan(hypot(xy.x,xy.y) - Q->ctgphi1);
@@ -66,22 +68,22 @@ static LP inverse (XY xy, PJ *P) {
 }
 
 
-static void *destructor (PJ *P, int errlev) {
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->en);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
     return pj_default_destructor (P, errlev);
 }
 
 
 PJ *PROJECTION(ccon) {
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
diff --git a/src/PJ_cea.c b/src/projections/cea.cpp
index e05e524b..f8275b62 100644
--- a/src/PJ_cea.c
+++ b/src/projections/cea.cpp
@@ -6,10 +6,12 @@
 #include "proj.h"
 #include "projects.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double qp;
     double *apa;
 };
+} // anonymous namespace
 
 PROJ_HEAD(cea, "Equal Area Cylindrical") "\n\tCyl, Sph&Ell\n\tlat_ts=";
 # define EPS    1e-10
@@ -33,7 +35,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    lp.phi = pj_authlat(asin( 2. * xy.y * P->k0 / P->opaque->qp), P->opaque->apa);
+    lp.phi = pj_authlat(asin( 2. * xy.y * P->k0 / static_cast<struct pj_opaque*>(P->opaque)->qp), static_cast<struct pj_opaque*>(P->opaque)->apa);
     lp.lam = xy.x / P->k0;
     return lp;
 }
@@ -56,22 +58,22 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     return (lp);
 }
 
-static void *destructor (PJ *P, int errlev) {                        /* Destructor */
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {                        /* Destructor */
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->apa);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->apa);
     return pj_default_destructor (P, errlev);
 }
 
 
 PJ *PROJECTION(cea) {
     double t = 0.0;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
diff --git a/src/PJ_chamb.c b/src/projections/chamb.cpp
index 6951d6a1..a490e817 100644
--- a/src/PJ_chamb.c
+++ b/src/projections/chamb.cpp
@@ -7,6 +7,7 @@
 #include "projects.h"
 
 typedef struct { double r, Az; } VECT;
+namespace { // anonymous namespace
 struct pj_opaque {
     struct { /* control point data */
         double phi, lam;
@@ -18,6 +19,7 @@ struct pj_opaque {
     XY p;
     double beta_0, beta_1, beta_2;
 };
+} // anonymous namespace
 
 PROJ_HEAD(chamb, "Chamberlin Trimetric") "\n\tMisc Sph, no inv"
 "\n\tlat_1= lon_1= lat_2= lon_2= lat_3= lon_3=";
@@ -54,7 +56,7 @@ static double lc(projCtx ctx, double b,double c,double a) {
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy;
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double sinphi, cosphi, a;
     VECT v[3];
     int i, j;
@@ -101,8 +103,8 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 PJ *PROJECTION(chamb) {
     int i, j;
     char line[10];
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_collg.c b/src/projections/collg.cpp
index 7904de29..7904de29 100644
--- a/src/PJ_collg.c
+++ b/src/projections/collg.cpp
diff --git a/src/PJ_comill.c b/src/projections/comill.cpp
index b6e0192e..b6e0192e 100644
--- a/src/PJ_comill.c
+++ b/src/projections/comill.cpp
diff --git a/src/PJ_crast.c b/src/projections/crast.cpp
index 4e4dee8b..4e4dee8b 100644
--- a/src/PJ_crast.c
+++ b/src/projections/crast.cpp
diff --git a/src/PJ_denoy.c b/src/projections/denoy.cpp
index 5c337c45..5c337c45 100644
--- a/src/PJ_denoy.c
+++ b/src/projections/denoy.cpp
diff --git a/src/PJ_eck1.c b/src/projections/eck1.cpp
index 88a7430c..88a7430c 100644
--- a/src/PJ_eck1.c
+++ b/src/projections/eck1.cpp
diff --git a/src/PJ_eck2.c b/src/projections/eck2.cpp
index f76ab4ec..f76ab4ec 100644
--- a/src/PJ_eck2.c
+++ b/src/projections/eck2.cpp
diff --git a/src/PJ_eck3.c b/src/projections/eck3.cpp
index 8f91c8bb..90376631 100644
--- a/src/PJ_eck3.c
+++ b/src/projections/eck3.cpp
@@ -10,14 +10,16 @@ PROJ_HEAD(putp1, "Putnins P1") "\n\tPCyl, Sph";
 PROJ_HEAD(wag6, "Wagner VI") "\n\tPCyl, Sph";
 PROJ_HEAD(kav7, "Kavraisky VII") "\n\tPCyl, Sph";
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double C_x, C_y, A, B;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     xy.y = Q->C_y * lp.phi;
     xy.x = Q->C_x * lp.lam * (Q->A + asqrt(1. - Q->B * lp.phi * lp.phi));
@@ -27,7 +29,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double denominator;
 
     lp.phi = xy.y / Q->C_y;
@@ -49,8 +51,8 @@ static PJ *setup(PJ *P) {
 
 
 PJ *PROJECTION(eck3) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -64,8 +66,8 @@ PJ *PROJECTION(eck3) {
 
 
 PJ *PROJECTION(kav7) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -82,8 +84,8 @@ PJ *PROJECTION(kav7) {
 
 
 PJ *PROJECTION(wag6) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -96,8 +98,8 @@ PJ *PROJECTION(wag6) {
 
 
 PJ *PROJECTION(putp1) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_eck4.c b/src/projections/eck4.cpp
index 4fa4c21f..4fa4c21f 100644
--- a/src/PJ_eck4.c
+++ b/src/projections/eck4.cpp
diff --git a/src/PJ_eck5.c b/src/projections/eck5.cpp
index f9f28460..f9f28460 100644
--- a/src/PJ_eck5.c
+++ b/src/projections/eck5.cpp
diff --git a/src/PJ_eqc.c b/src/projections/eqc.cpp
index 07d6141c..3fdb6dc0 100644
--- a/src/PJ_eqc.c
+++ b/src/projections/eqc.cpp
@@ -6,9 +6,11 @@
 #include "proj.h"
 #include "projects.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double rc;
 };
+} // anonymous namespace
 
 PROJ_HEAD(eqc, "Equidistant Cylindrical (Plate Carree)")
     "\n\tCyl, Sph\n\tlat_ts=[, lat_0=0]";
@@ -16,7 +18,7 @@ PROJ_HEAD(eqc, "Equidistant Cylindrical (Plate Carree)")
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     xy.x = Q->rc * lp.lam;
     xy.y = lp.phi - P->phi0;
@@ -27,7 +29,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     lp.lam = xy.x / Q->rc;
     lp.phi = xy.y + P->phi0;
@@ -37,8 +39,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(eqc) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_eqdc.c b/src/projections/eqdc.cpp
index 8caca87a..0831fca4 100644
--- a/src/PJ_eqdc.c
+++ b/src/projections/eqdc.cpp
@@ -7,6 +7,7 @@
 #include "projects.h"
 #include "proj_math.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double phi1;
     double phi2;
@@ -17,6 +18,7 @@ struct pj_opaque {
     double *en;
     int     ellips;
 };
+} // anonymous namespace
 
 PROJ_HEAD(eqdc, "Equidistant Conic")
     "\n\tConic, Sph&Ell\n\tlat_1= lat_2=";
@@ -25,7 +27,7 @@ PROJ_HEAD(eqdc, "Equidistant Conic")
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     Q->rho = Q->c - (Q->ellips ? pj_mlfn(lp.phi, sin(lp.phi),
         cos(lp.phi), Q->en) : lp.phi);
@@ -38,7 +40,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     if ((Q->rho = hypot(xy.x, xy.y = Q->rho0 - xy.y)) != 0.0 ) {
         if (Q->n < 0.) {
@@ -58,14 +60,14 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 }
 
 
-static void *destructor (PJ *P, int errlev) {                        /* Destructor */
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {                        /* Destructor */
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->en);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
     return pj_default_destructor (P, errlev);
 }
 
@@ -74,8 +76,8 @@ PJ *PROJECTION(eqdc) {
     double cosphi, sinphi;
     int secant;
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
diff --git a/src/PJ_eqearth.c b/src/projections/eqearth.cpp
index a0d4467b..e5c1f974 100644
--- a/src/PJ_eqearth.c
+++ b/src/projections/eqearth.cpp
@@ -31,15 +31,17 @@ PROJ_HEAD(eqearth, "Equal Earth") "\n\tPCyl, Sph&Ell";
 #define EPS 1e-11
 #define MAX_ITER 12
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  qp;
     double  rqda;
     double *apa;
 };
+} // anonymous namespace
 
 static XY e_forward (LP lp, PJ *P) {           /* Ellipsoidal/spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double sbeta;
     double psi, psi2, psi6;
 
@@ -73,7 +75,7 @@ static XY e_forward (LP lp, PJ *P) {           /* Ellipsoidal/spheroidal, forwar
 
 static LP e_inverse (XY xy, PJ *P) {           /* Ellipsoidal/spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double yc, y2, y6;
     int i;
 
@@ -127,21 +129,21 @@ static LP e_inverse (XY xy, PJ *P) {           /* Ellipsoidal/spheroidal, invers
     return lp;
 }
 
-static void *destructor (PJ *P, int errlev) { /* Destructor */
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) { /* Destructor */
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->apa);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->apa);
     return pj_default_destructor (P, errlev);
 }
 
 
 PJ *PROJECTION(eqearth) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
@@ -152,7 +154,7 @@ PJ *PROJECTION(eqearth) {
     /* Ellipsoidal case */
     if (P->es != 0.0) {
        Q->apa = pj_authset(P->es); /* For auth_lat(). */
-       if (0 == Q->apa)
+       if (nullptr == Q->apa)
           return destructor(P, ENOMEM);
        Q->qp = pj_qsfn(1.0, P->e, P->one_es); /* For auth_lat(). */
        Q->rqda = sqrt(0.5*Q->qp); /* Authalic radius divided by major axis */
diff --git a/src/proj_etmerc.c b/src/projections/etmerc.cpp
index 4d7187e6..05f86f37 100644
--- a/src/proj_etmerc.c
+++ b/src/projections/etmerc.cpp
@@ -47,6 +47,7 @@
 #include "proj_math.h"
 
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double    Qn;    /* Merid. quad., scaled to the projection */ \
     double    Zb;    /* Radius vector in polar coord. systems  */ \
@@ -55,6 +56,7 @@ struct pj_opaque {
     double    utg[6]; /* Constants for transv. merc. -> geo */ \
     double    gtu[6]; /* Constants for geo -> transv. merc. */
 };
+} // anonymous namespace
 
 PROJ_HEAD(etmerc, "Extended Transverse Mercator")
     "\n\tCyl, Sph\n\tlat_ts=(0)\nlat_0=(0)";
@@ -145,7 +147,7 @@ static double clens(double *a, int size, double arg_r) {
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double sin_Cn, cos_Cn, cos_Ce, sin_Ce, dCn, dCe;
     double Cn = lp.phi, Ce = lp.lam;
 
@@ -181,7 +183,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double sin_Cn, cos_Cn, cos_Ce, sin_Ce, dCn, dCe;
     double Cn = xy.y, Ce = xy.x;
 
@@ -218,7 +220,7 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 
 static PJ *setup(PJ *P) { /* general initialization */
     double f, n, np, Z;
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     if (P->es <= 0) {
         return pj_default_destructor(P, PJD_ERR_ELLIPSOID_USE_REQUIRED);
@@ -306,8 +308,8 @@ static PJ *setup(PJ *P) { /* general initialization */
 
 
 PJ *PROJECTION(etmerc) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
    return setup (P);
@@ -320,8 +322,8 @@ PJ *PROJECTION(etmerc) {
 
 PJ *PROJECTION(utm) {
     long zone;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_fahey.c b/src/projections/fahey.cpp
index 85e0ab69..85e0ab69 100644
--- a/src/PJ_fahey.c
+++ b/src/projections/fahey.cpp
diff --git a/src/PJ_fouc_s.c b/src/projections/fouc_s.cpp
index 6efe34bd..c5e711de 100644
--- a/src/PJ_fouc_s.c
+++ b/src/projections/fouc_s.cpp
@@ -11,14 +11,16 @@ PROJ_HEAD(fouc_s, "Foucaut Sinusoidal") "\n\tPCyl, Sph";
 #define MAX_ITER    10
 #define LOOP_TOL    1e-7
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double n, n1;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double t;
 
     t = cos(lp.phi);
@@ -30,7 +32,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double V;
     int i;
 
@@ -53,8 +55,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(fouc_s) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_gall.c b/src/projections/gall.cpp
index a8697482..a8697482 100644
--- a/src/PJ_gall.c
+++ b/src/projections/gall.cpp
diff --git a/src/PJ_geos.c b/src/projections/geos.cpp
index 0eb25610..90fb01ab 100644
--- a/src/PJ_geos.c
+++ b/src/projections/geos.cpp
@@ -36,6 +36,7 @@
 #include "projects.h"
 #include "proj_math.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double h;
     double radius_p;
@@ -46,13 +47,14 @@ struct pj_opaque {
     double C;
     int flip_axis;
 };
+} // anonymous namespace
 
 PROJ_HEAD(geos, "Geostationary Satellite View") "\n\tAzi, Sph&Ell\n\th=";
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double Vx, Vy, Vz, tmp;
 
     /* Calculation of the three components of the vector from satellite to
@@ -82,7 +84,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double r, Vx, Vy, Vz, tmp;
 
     /* Calculation of geocentric latitude. */
@@ -118,7 +120,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double Vx, Vy, Vz, a, b, det, k;
 
     /* Setting three components of vector from satellite to position.*/
@@ -155,7 +157,7 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double Vx, Vy, Vz, a, b, det, k;
 
     /* Setting three components of vector from satellite to position.*/
@@ -195,8 +197,8 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 
 PJ *PROJECTION(geos) {
     char *sweep_axis;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -204,7 +206,7 @@ PJ *PROJECTION(geos) {
         return pj_default_destructor (P, PJD_ERR_H_LESS_THAN_ZERO);
 
     sweep_axis = pj_param(P->ctx, P->params, "ssweep").s;
-    if (sweep_axis == NULL)
+    if (sweep_axis == nullptr)
       Q->flip_axis = 0;
     else {
         if ((sweep_axis[0] != 'x' && sweep_axis[0] != 'y') ||
diff --git a/src/PJ_gins8.c b/src/projections/gins8.cpp
index c1a2fff0..cc422437 100644
--- a/src/PJ_gins8.c
+++ b/src/projections/gins8.cpp
@@ -24,7 +24,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 PJ *PROJECTION(gins8) {
     P->es = 0.0;
-    P->inv = 0;
+    P->inv = nullptr;
     P->fwd = s_forward;
 
     return P;
diff --git a/src/PJ_gn_sinu.c b/src/projections/gn_sinu.cpp
index 2ef0f263..530de229 100644
--- a/src/PJ_gn_sinu.c
+++ b/src/projections/gn_sinu.cpp
@@ -15,17 +15,19 @@ PROJ_HEAD(mbtfps, "McBryde-Thomas Flat-Polar Sinusoidal") "\n\tPCyl, Sph";
 #define MAX_ITER 8
 #define LOOP_TOL 1e-7
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double *en;
     double m, n, C_x, C_y;
 };
+} // anonymous namespace
 
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
     double s, c;
 
-    xy.y = pj_mlfn(lp.phi, s = sin(lp.phi), c = cos(lp.phi), P->opaque->en);
+    xy.y = pj_mlfn(lp.phi, s = sin(lp.phi), c = cos(lp.phi), static_cast<struct pj_opaque*>(P->opaque)->en);
     xy.x = lp.lam * c / sqrt(1. - P->es * s * s);
     return xy;
 }
@@ -35,7 +37,7 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
     double s;
 
-    if ((s = fabs(lp.phi = pj_inv_mlfn(P->ctx, xy.y, P->es, P->opaque->en))) < M_HALFPI) {
+    if ((s = fabs(lp.phi = pj_inv_mlfn(P->ctx, xy.y, P->es, static_cast<struct pj_opaque*>(P->opaque)->en))) < M_HALFPI) {
         s = sin(lp.phi);
         lp.lam = xy.x * sqrt(1. - P->es * s * s) / cos(lp.phi);
     } else if ((s - EPS10) < M_HALFPI) {
@@ -50,7 +52,7 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     if (Q->m == 0.0)
         lp.phi = Q->n != 1. ? aasin(P->ctx,Q->n * sin(lp.phi)): lp.phi;
@@ -80,7 +82,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     xy.y /= Q->C_y;
     lp.phi = (Q->m != 0.0) ? aasin(P->ctx,(Q->m * xy.y + sin(xy.y)) / Q->n) :
@@ -90,14 +92,14 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 }
 
 
-static void *destructor (PJ *P, int errlev) {                        /* Destructor */
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {                        /* Destructor */
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->en);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
     return pj_default_destructor (P, errlev);
 }
 
@@ -105,7 +107,7 @@ static void *destructor (PJ *P, int errlev) {                        /* Destruct
 
 /* for spheres, only */
 static void setup(PJ *P) {
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     P->es = 0;
     P->inv = s_inverse;
     P->fwd = s_forward;
@@ -115,8 +117,8 @@ static void setup(PJ *P) {
 
 
 PJ *PROJECTION(sinu) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
@@ -137,8 +139,8 @@ PJ *PROJECTION(sinu) {
 
 
 PJ *PROJECTION(eck6) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
@@ -152,8 +154,8 @@ PJ *PROJECTION(eck6) {
 
 
 PJ *PROJECTION(mbtfps) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
@@ -167,8 +169,8 @@ PJ *PROJECTION(mbtfps) {
 
 
 PJ *PROJECTION(gn_sinu) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
diff --git a/src/PJ_gnom.c b/src/projections/gnom.cpp
index 635ae49e..a4b5e35d 100644
--- a/src/PJ_gnom.c
+++ b/src/projections/gnom.cpp
@@ -11,23 +11,27 @@ PROJ_HEAD(gnom, "Gnomonic") "\n\tAzi, Sph";
 
 #define EPS10  1.e-10
 
+namespace { // anonymous namespace
 enum Mode {
     N_POLE = 0,
     S_POLE = 1,
     EQUIT  = 2,
     OBLIQ  = 3
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  sinph0;
     double  cosph0;
     enum Mode mode;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  coslam, cosphi, sinphi;
 
     sinphi = sin(lp.phi);
@@ -75,7 +79,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  rh, cosz, sinz;
 
     rh = hypot(xy.x, xy.y);
@@ -120,8 +124,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(gnom) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_goode.c b/src/projections/goode.cpp
index 8d8ac24d..c79d125e 100644
--- a/src/PJ_goode.c
+++ b/src/projections/goode.cpp
@@ -13,15 +13,17 @@ PROJ_HEAD(goode, "Goode Homolosine") "\n\tPCyl, Sph";
 
 C_NAMESPACE PJ *pj_sinu(PJ *), *pj_moll(PJ *);
 
+namespace { // anonymous namespace
 struct pj_opaque {
     PJ *sinu;
     PJ *moll;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy;
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     if (fabs(lp.phi) <= PHI_LIM)
         xy = Q->sinu->fwd(lp, Q->sinu);
@@ -35,7 +37,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp;
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     if (fabs(xy.y) <= PHI_LIM)
         lp = Q->sinu->inv(xy, Q->sinu);
@@ -47,27 +49,27 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 }
 
 
-static void *destructor (PJ *P, int errlev) {              /* Destructor */
-    if (0==P)
-        return 0;
-    if (0==P->opaque)
+static PJ *destructor (PJ *P, int errlev) {              /* Destructor */
+    if (nullptr==P)
+        return nullptr;
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
-    pj_free (P->opaque->sinu);
-    pj_free (P->opaque->moll);
+    pj_free (static_cast<struct pj_opaque*>(P->opaque)->sinu);
+    pj_free (static_cast<struct pj_opaque*>(P->opaque)->moll);
     return pj_default_destructor (P, errlev);
 }
 
 
 
 PJ *PROJECTION(goode) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
 
     P->es = 0.;
-    if (!(Q->sinu = pj_sinu(0)) || !(Q->moll = pj_moll(0)))
+    if (!(Q->sinu = pj_sinu(nullptr)) || !(Q->moll = pj_moll(nullptr)))
         return destructor (P, ENOMEM);
     Q->sinu->es = 0.;
     Q->sinu->ctx = P->ctx;
diff --git a/src/PJ_gstmerc.c b/src/projections/gstmerc.cpp
index 5b5109b0..9b819bac 100644
--- a/src/PJ_gstmerc.c
+++ b/src/projections/gstmerc.cpp
@@ -8,6 +8,7 @@
 PROJ_HEAD(gstmerc, "Gauss-Schreiber Transverse Mercator (aka Gauss-Laborde Reunion)")
     "\n\tCyl, Sph&Ell\n\tlat_0= lon_0= k_0=";
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double lamc;
     double phic;
@@ -17,11 +18,12 @@ struct pj_opaque {
     double XS;
     double YS;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double L, Ls, sinLs1, Ls1;
 
     L = Q->n1*lp.lam;
@@ -37,7 +39,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double L, LC, sinC;
 
     L = atan(sinh((xy.x * P->a - Q->XS) / Q->n2) / cos((xy.y * P->a - Q->YS) / Q->n2));
@@ -51,8 +53,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(gstmerc) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_hammer.c b/src/projections/hammer.cpp
index f3e0d64e..d4caa656 100644
--- a/src/PJ_hammer.c
+++ b/src/projections/hammer.cpp
@@ -11,15 +11,17 @@ PROJ_HEAD(hammer, "Hammer & Eckert-Greifendorff")
 
 #define EPS 1.0e-10
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double w;
     double m, rm;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double cosphi, d;
 
     d = sqrt(2./(1. + (cosphi = cos(lp.phi)) * cos(lp.lam *= Q->w)));
@@ -31,7 +33,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double z;
 
     z = sqrt(1. - 0.25*Q->w*Q->w*xy.x*xy.x - 0.25*xy.y*xy.y);
@@ -48,8 +50,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(hammer) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_hatano.c b/src/projections/hatano.cpp
index 019671cc..019671cc 100644
--- a/src/PJ_hatano.c
+++ b/src/projections/hatano.cpp
diff --git a/src/PJ_healpix.c b/src/projections/healpix.cpp
index 3a88695f..7f0b3e83 100644
--- a/src/PJ_healpix.c
+++ b/src/projections/healpix.cpp
@@ -53,12 +53,14 @@ PROJ_HEAD(rhealpix, "rHEALPix") "\n\tSph&Ell\n\tnorth_square= south_square=";
 /* Fuzz to handle rounding errors: */
 # define EPS 1e-15
 
+namespace { // anonymous namespace
 struct pj_opaque {
     int north_square;
     int south_square;
     double qp;
     double *apa;
 };
+} // anonymous namespace
 
 typedef struct {
     int cn;         /* An integer 0--3 indicating the position of the polar cap. */
@@ -229,7 +231,7 @@ static int in_image(double x, double y, int proj, int north_square,
  * P contains the relevant ellipsoid parameters.
  **/
 static double auth_lat(PJ *P, double alpha, int inverse) {
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     if (inverse == 0) {
         /* Authalic latitude. */
         double q = pj_qsfn(sin(alpha), P->e, 1.0 - P->es);
@@ -366,13 +368,13 @@ static CapMap get_cap(double x, double y, int north_square, int south_square,
     capmap.y = y;
     if (inverse == 0) {
         if (y > M_FORTPI) {
-            capmap.region = north;
+            capmap.region = CapMap::north;
             c = M_HALFPI;
         } else if (y < -M_FORTPI) {
-            capmap.region = south;
+            capmap.region = CapMap::south;
             c = -M_HALFPI;
         } else {
-            capmap.region = equatorial;
+            capmap.region = CapMap::equatorial;
             capmap.cn = 0;
             return capmap;
         }
@@ -396,23 +398,23 @@ static CapMap get_cap(double x, double y, int north_square, int south_square,
         }
     } else {
         if (y > M_FORTPI) {
-            capmap.region = north;
+            capmap.region = CapMap::north;
             capmap.x = -3*M_FORTPI + north_square*M_HALFPI;
             capmap.y = M_HALFPI;
             x = x - north_square*M_HALFPI;
         } else if (y < -M_FORTPI) {
-            capmap.region = south;
+            capmap.region = CapMap::south;
             capmap.x = -3*M_FORTPI + south_square*M_HALFPI;
             capmap.y = -M_HALFPI;
             x = x - south_square*M_HALFPI;
         } else {
-            capmap.region = equatorial;
+            capmap.region = CapMap::equatorial;
             capmap.cn = 0;
             return capmap;
         }
         /* Polar Region, find the HEALPix polar cap number that
            x, y moves to when rHEALPix polar square is disassembled. */
-        if (capmap.region == north) {
+        if (capmap.region == CapMap::north) {
             if (y >= -x - M_FORTPI - EPS && y < x + 5*M_FORTPI - EPS) {
                 capmap.cn = (north_square + 1) % 4;
             } else if (y > -x -M_FORTPI + EPS && y >= x + 5*M_FORTPI - EPS) {
@@ -422,7 +424,7 @@ static CapMap get_cap(double x, double y, int north_square, int south_square,
             } else {
                 capmap.cn = north_square;
             }
-        } else if (capmap.region == south) {
+        } else if (capmap.region == CapMap::south) {
             if (y <= x + M_FORTPI + EPS && y > -x - 5*M_FORTPI + EPS) {
                 capmap.cn = (south_square + 1) % 4;
             } else if (y < x + M_FORTPI - EPS && y <= -x - 5*M_FORTPI + EPS) {
@@ -459,7 +461,7 @@ static XY combine_caps(double x, double y, int north_square, int south_square,
     int pole = 0;
 
     CapMap capmap = get_cap(x, y, north_square, south_square, inverse);
-    if (capmap.region == equatorial) {
+    if (capmap.region == CapMap::equatorial) {
         xy.x = capmap.x;
         xy.y = capmap.y;
         return xy;
@@ -472,7 +474,7 @@ static XY combine_caps(double x, double y, int north_square, int south_square,
         /* Rotate (x, y) about its polar cap tip and then translate it to
            north_square or south_square. */
 
-        if (capmap.region == north) {
+        if (capmap.region == CapMap::north) {
             pole = north_square;
             tmpRot = rot[get_rotate_index(capmap.cn - pole)];
         } else {
@@ -484,7 +486,7 @@ static XY combine_caps(double x, double y, int north_square, int south_square,
          Unrotate (x, y) and then translate it back. */
 
         /* disassemble */
-        if (capmap.region == north) {
+        if (capmap.region == CapMap::north) {
             pole = north_square;
             tmpRot = rot[get_rotate_index(-1*(capmap.cn - pole))];
         } else {
@@ -500,7 +502,7 @@ static XY combine_caps(double x, double y, int north_square, int south_square,
         /* Workaround cppcheck git issue */
         double* pa = a;
         pa[0] = -3*M_FORTPI + ((inverse == 0) ? pole : capmap.cn) *M_HALFPI;
-        pa[1] = ((capmap.region == north) ? 1 : -1) *M_HALFPI;
+        pa[1] = ((capmap.region == CapMap::north) ? 1 : -1) *M_HALFPI;
         vector_add(ret_dot, a, vector);
     }
 
@@ -552,7 +554,7 @@ static LP e_healpix_inverse(XY xy, PJ *P) { /* ellipsoid */
 
 
 static XY s_rhealpix_forward(LP lp, PJ *P) { /* sphere */
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     XY xy = healpix_sphere(lp);
     return combine_caps(xy.x, xy.y, Q->north_square, Q->south_square, 0);
@@ -560,7 +562,7 @@ static XY s_rhealpix_forward(LP lp, PJ *P) { /* sphere */
 
 
 static XY e_rhealpix_forward(LP lp, PJ *P) { /* ellipsoid */
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     XY xy;
     lp.phi = auth_lat(P, lp.phi, 0);
     xy = healpix_sphere(lp);
@@ -569,7 +571,7 @@ static XY e_rhealpix_forward(LP lp, PJ *P) { /* ellipsoid */
 
 
 static LP s_rhealpix_inverse(XY xy, PJ *P) { /* sphere */
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     /* Check whether (x, y) lies in the rHEALPix image. */
     if (in_image(xy.x, xy.y, 1, Q->north_square, Q->south_square) == 0) {
@@ -585,7 +587,7 @@ static LP s_rhealpix_inverse(XY xy, PJ *P) { /* sphere */
 
 
 static LP e_rhealpix_inverse(XY xy, PJ *P) { /* ellipsoid */
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     LP lp = {0.0,0.0};
 
     /* Check whether (x, y) lies in the rHEALPix image. */
@@ -602,28 +604,28 @@ static LP e_rhealpix_inverse(XY xy, PJ *P) { /* ellipsoid */
 }
 
 
-static void *destructor (PJ *P, int errlev) {                        /* Destructor */
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {                        /* Destructor */
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->apa);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->apa);
     return pj_default_destructor (P, errlev);
 }
 
 
 PJ *PROJECTION(healpix) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
 
     if (P->es != 0.0) {
         Q->apa = pj_authset(P->es);             /* For auth_lat(). */
-        if (0==Q->apa)
+        if (nullptr==Q->apa)
             return destructor(P, ENOMEM);
         Q->qp = pj_qsfn(1.0, P->e, P->one_es);  /* For auth_lat(). */
         P->a = P->a*sqrt(0.5*Q->qp);            /* Set P->a to authalic radius. */
@@ -640,8 +642,8 @@ PJ *PROJECTION(healpix) {
 
 
 PJ *PROJECTION(rhealpix) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
@@ -656,7 +658,7 @@ PJ *PROJECTION(rhealpix) {
         return destructor (P, PJD_ERR_AXIS);
     if (P->es != 0.0) {
         Q->apa = pj_authset(P->es); /* For auth_lat(). */
-        if (0==Q->apa)
+        if (nullptr==Q->apa)
             return destructor(P, ENOMEM);
         Q->qp = pj_qsfn(1.0, P->e, P->one_es); /* For auth_lat(). */
         P->a = P->a*sqrt(0.5*Q->qp); /* Set P->a to authalic radius. */
diff --git a/src/PJ_igh.c b/src/projections/igh.cpp
index c991649a..e3576861 100644
--- a/src/PJ_igh.c
+++ b/src/projections/igh.cpp
@@ -32,15 +32,17 @@ static const double d180 = 180 * DEG_TO_RAD;
 
 static const double EPSLN = 1.e-10; /* allow a little 'slack' on zone edge positions */
 
+namespace { // anonymous namespace
 struct pj_opaque {
     struct PJconsts* pj[12]; \
     double dy0;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy;
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     int z;
 
     if (lp.phi >=  d4044118) {          /* 1|2 */
@@ -73,7 +75,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     const double y90 = Q->dy0 + sqrt(2); /* lt=90 corresponds to y=y0+sqrt(2) */
 
     int z = 0;
@@ -134,17 +136,17 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 }
 
 
-static void *destructor (PJ *P, int errlev) {
+static PJ *destructor (PJ *P, int errlev) {
     int i;
-    if (0==P)
-        return 0;
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
     for (i = 0; i < 12; ++i) {
-        if (P->opaque->pj[i])
-            P->opaque->pj[i]->destructor(P->opaque->pj[i], errlev);
+        if (static_cast<struct pj_opaque*>(P->opaque)->pj[i])
+            static_cast<struct pj_opaque*>(P->opaque)->pj[i]->destructor(static_cast<struct pj_opaque*>(P->opaque)->pj[i], errlev);
     }
 
     return pj_default_destructor(P, errlev);
@@ -173,7 +175,7 @@ static void *destructor (PJ *P, int errlev) {
 */
 
 #define SETUP(n, proj, x_0, y_0, lon_0) \
-    if (!(Q->pj[n-1] = pj_##proj(0))) return destructor(P, ENOMEM); \
+    if (!(Q->pj[n-1] = pj_##proj(nullptr))) return destructor(P, ENOMEM); \
     if (!(Q->pj[n-1] = pj_##proj(Q->pj[n-1]))) return destructor(P, ENOMEM); \
     Q->pj[n-1]->ctx = P->ctx; \
     Q->pj[n-1]->x0 = x_0; \
@@ -184,8 +186,8 @@ static void *destructor (PJ *P, int errlev) {
 PJ *PROJECTION(igh) {
     XY xy1, xy3;
     LP lp = { 0, d4044118 };
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_imw_p.c b/src/projections/imw_p.cpp
index abed5006..012c5caa 100644
--- a/src/PJ_imw_p.c
+++ b/src/projections/imw_p.cpp
@@ -12,22 +12,26 @@ PROJ_HEAD(imw_p, "International Map of the World Polyconic")
 #define TOL 1e-10
 #define EPS 1e-10
 
+namespace { // anonymous namespace
 enum Mode {
     NONE_IS_ZERO  =  0, /* phi_1 and phi_2 != 0 */
     PHI_1_IS_ZERO =  1, /* phi_1 = 0 */
     PHI_2_IS_ZERO = -1  /* phi_2 = 0 */
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  P, Pp, Q, Qp, R_1, R_2, sphi_1, sphi_2, C2;
     double  phi_1, phi_2, lam_1;
     double  *en;
     enum Mode mode;
 };
+} // anonymous namespace
 
 
 static int phi12(PJ *P, double *del, double *sig) {
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     int err = 0;
 
     if (!pj_param(P->ctx, P->params, "tlat_1").i ||
@@ -45,7 +49,7 @@ static int phi12(PJ *P, double *del, double *sig) {
 
 
 static XY loc_for(LP lp, PJ *P, double *yc) {
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     XY xy;
 
     if (lp.phi == 0.0) {
@@ -102,7 +106,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     XY t;
     double yc = 0.0;
     int i = 0;
@@ -132,21 +136,21 @@ static void xy(PJ *P, double phi, double *x, double *y, double *sp, double *R) {
 
     *sp = sin(phi);
     *R = 1./(tan(phi) * sqrt(1. - P->es * *sp * *sp ));
-    F = P->opaque->lam_1 * *sp;
+    F = static_cast<struct pj_opaque*>(P->opaque)->lam_1 * *sp;
     *y = *R * (1 - cos(F));
     *x = *R * sin(F);
 }
 
 
-static void *destructor (PJ *P, int errlev) {
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    if( P->opaque->en )
-        pj_dealloc (P->opaque->en);
+    if( static_cast<struct pj_opaque*>(P->opaque)->en )
+        pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
 
     return pj_default_destructor(P, errlev);
 }
@@ -155,8 +159,8 @@ static void *destructor (PJ *P, int errlev) {
 PJ *PROJECTION(imw_p) {
     double del, sig, s, t, x1, x2, T2, y1, m1, m2, y2;
     int err;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_isea.c b/src/projections/isea.cpp
index 4ffd2983..522e6813 100644
--- a/src/PJ_isea.c
+++ b/src/projections/isea.cpp
@@ -46,10 +46,12 @@
 #define ISEA_STD_LAT 1.01722196792335072101
 #define ISEA_STD_LON .19634954084936207740
 
+namespace { // anonymous namespace
 struct hex {
         int iso;
         long x, y, z;
 };
+} // anonymous namespace
 
 /* y *must* be positive down as the xy /iso conversion assumes this */
 static void hex_xy(struct hex *h) {
@@ -124,12 +126,15 @@ static void hexbin2(double width, double x, double y, long *i, long *j) {
     *j = h.y;
 }
 
+namespace { // anonymous namespace
 enum isea_poly { ISEA_NONE, ISEA_ICOSAHEDRON = 20 };
 enum isea_topology { ISEA_HEXAGON=6, ISEA_TRIANGLE=3, ISEA_DIAMOND=4 };
 enum isea_address_form { ISEA_GEO, ISEA_Q2DI, ISEA_SEQNUM, ISEA_INTERLEAVE,
     ISEA_PLANE, ISEA_Q2DD, ISEA_PROJTRI, ISEA_VERTEX2DD, ISEA_HEX
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct isea_dgg {
     int polyhedron; /* ignored, icosahedron */
     double  o_lat, o_lon, o_az; /* orientation, radians */
@@ -143,29 +148,38 @@ struct isea_dgg {
     int quad; /* quad of last transformed point */
     unsigned long serial;
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct isea_pt {
     double x, y;
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct isea_geo {
     double lon, lat;
 };
+} // anonymous namespace
 
 /* ENDINC */
 
+namespace { // anonymous namespace
 enum snyder_polyhedron {
     SNYDER_POLY_HEXAGON, SNYDER_POLY_PENTAGON,
     SNYDER_POLY_TETRAHEDRON, SNYDER_POLY_CUBE,
     SNYDER_POLY_OCTAHEDRON, SNYDER_POLY_DODECAHEDRON,
     SNYDER_POLY_ICOSAHEDRON
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct snyder_constants {
     double          g, G, theta;
     /* cppcheck-suppress unusedStructMember */
     double ea_w, ea_a, ea_b, g_w, g_a, g_b;
 };
+} // anonymous namespace
 
 /* TODO put these in radians to avoid a later conversion */
 static const struct snyder_constants constants[] = {
@@ -974,14 +988,16 @@ static struct isea_pt isea_forward(struct isea_dgg *g, struct isea_geo *in)
 
 PROJ_HEAD(isea, "Icosahedral Snyder Equal Area") "\n\tSph";
 
+namespace { // anonymous namespace
 struct pj_opaque {
     struct isea_dgg dgg;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     struct isea_pt out;
     struct isea_geo in;
 
@@ -999,8 +1015,8 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 PJ *PROJECTION(isea) {
     char *opt;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_krovak.c b/src/projections/krovak.cpp
index 5ca21214..9ecffb89 100644
--- a/src/PJ_krovak.c
+++ b/src/projections/krovak.cpp
@@ -90,6 +90,7 @@ PROJ_HEAD(krovak, "Krovak") "\n\tPCyl, Ell";
 /* Not sure at all of the appropriate number for MAX_ITER... */
 #define MAX_ITER 100
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double alpha;
     double k;
@@ -98,10 +99,11 @@ struct pj_opaque {
     double ad;
     int czech;
 };
+} // anonymous namespace
 
 
 static XY e_forward (LP lp, PJ *P) {                /* Ellipsoidal, forward */
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     XY xy = {0.0,0.0};
 
     double gfi, u, deltav, s, d, eps, rho;
@@ -128,7 +130,7 @@ static XY e_forward (LP lp, PJ *P) {                /* Ellipsoidal, forward */
 
 
 static LP e_inverse (XY xy, PJ *P) {                /* Ellipsoidal, inverse */
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     LP lp = {0.0,0.0};
 
     double u, deltav, s, d, eps, rho, fi1, xy0;
@@ -176,8 +178,8 @@ static LP e_inverse (XY xy, PJ *P) {                /* Ellipsoidal, inverse */
 
 PJ *PROJECTION(krovak) {
     double u0, n0, g;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_labrd.c b/src/projections/labrd.cpp
index 769dc620..d3930243 100644
--- a/src/PJ_labrd.c
+++ b/src/projections/labrd.cpp
@@ -8,14 +8,16 @@
 PROJ_HEAD(labrd, "Laborde") "\n\tCyl, Sph\n\tSpecial for Madagascar";
 #define EPS 1.e-10
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  kRg, p0s, A, C, Ca, Cb, Cc, Cd;
 };
+} // anonymous namespace
 
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double V1, V2, ps, sinps, cosps, sinps2, cosps2;
     double I1, I2, I3, I4, I5, I6, x2, y2, t;
 
@@ -48,7 +50,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     /* t = 0.0 optimization is to avoid a false positive cppcheck warning */
     /* (cppcheck git beaf29c15867984aa3c2a15cf15bd7576ccde2b3). Might no */
     /* longer be necessary with later versions. */
@@ -100,8 +102,8 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 
 PJ *PROJECTION(labrd) {
     double Az, sinp, R, N, t;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_laea.c b/src/projections/laea.cpp
index bcf9c44d..dd02c75a 100644
--- a/src/PJ_laea.c
+++ b/src/projections/laea.cpp
@@ -6,13 +6,16 @@
 
 PROJ_HEAD(laea, "Lambert Azimuthal Equal Area") "\n\tAzi, Sph&Ell";
 
+namespace { // anonymous namespace
 enum Mode {
     N_POLE = 0,
     S_POLE = 1,
     EQUIT  = 2,
     OBLIQ  = 3
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double sinb1;
     double cosb1;
@@ -25,12 +28,13 @@ struct pj_opaque {
     double *apa;
     enum Mode mode;
 };
+} // anonymous namespace
 
 #define EPS10   1.e-10
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double coslam, sinlam, sinphi, q, sinb=0.0, cosb=0.0, b=0.0;
 
     coslam = cos(lp.lam);
@@ -92,7 +96,7 @@ eqcon:
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  coslam, cosphi, sinphi;
 
     sinphi = sin(lp.phi);
@@ -134,7 +138,7 @@ oblcon:
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double cCe, sCe, q, rho, ab=0.0;
 
     switch (Q->mode) {
@@ -183,7 +187,7 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  cosz=0.0, rh, sinz=0.0;
 
     rh = hypot(xy.x, xy.y);
@@ -222,14 +226,14 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 }
 
 
-static void *destructor (PJ *P, int errlev) {
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->apa);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->apa);
 
     return pj_default_destructor(P, errlev);
 }
@@ -237,8 +241,8 @@ static void *destructor (PJ *P, int errlev) {
 
 PJ *PROJECTION(laea) {
     double t;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     P->destructor = destructor;
@@ -257,7 +261,7 @@ PJ *PROJECTION(laea) {
         Q->qp = pj_qsfn(1., P->e, P->one_es);
         Q->mmf = .5 / (1. - P->es);
         Q->apa = pj_authset(P->es);
-        if (0==Q->apa)
+        if (nullptr==Q->apa)
             return destructor(P, ENOMEM);
         switch (Q->mode) {
         case N_POLE:
diff --git a/src/PJ_lagrng.c b/src/projections/lagrng.cpp
index 3856fcdc..8c0150aa 100644
--- a/src/PJ_lagrng.c
+++ b/src/projections/lagrng.cpp
@@ -9,6 +9,7 @@ PROJ_HEAD(lagrng, "Lagrange") "\n\tMisc Sph\n\tW=";
 
 #define TOL 1e-10
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  a1;
     double  a2;
@@ -17,11 +18,12 @@ struct pj_opaque {
     double  rw;
     double  w;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double v, c;
 
     if (fabs(fabs(lp.phi) - M_HALFPI) < TOL) {
@@ -45,7 +47,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double c, x2, y2p, y2m;
 
     if (fabs(fabs(xy.y) - 2.) < TOL) {
@@ -69,8 +71,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 PJ *PROJECTION(lagrng) {
     double phi1;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_larr.c b/src/projections/larr.cpp
index e4d5d240..e4d5d240 100644
--- a/src/PJ_larr.c
+++ b/src/projections/larr.cpp
diff --git a/src/PJ_lask.c b/src/projections/lask.cpp
index 46f23edb..46f23edb 100644
--- a/src/PJ_lask.c
+++ b/src/projections/lask.cpp
diff --git a/src/PJ_latlong.c b/src/projections/latlong.cpp
index 1331d59a..1331d59a 100644
--- a/src/PJ_latlong.c
+++ b/src/projections/latlong.cpp
diff --git a/src/PJ_lcc.c b/src/projections/lcc.cpp
index 96aa3f2a..7d6e3f57 100644
--- a/src/PJ_lcc.c
+++ b/src/projections/lcc.cpp
@@ -9,6 +9,7 @@ PROJ_HEAD(lcc, "Lambert Conformal Conic")
 
 #define EPS10 1.e-10
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double phi1;
     double phi2;
@@ -16,11 +17,12 @@ struct pj_opaque {
     double rho0;
     double c;
 };
+} // anonymous namespace
 
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0., 0.};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double rho;
 
     if (fabs(fabs(lp.phi) - M_HALFPI) < EPS10) {
@@ -43,7 +45,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0., 0.};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double rho;
 
     xy.x /= P->k0;
@@ -78,9 +80,9 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 PJ *PROJECTION(lcc) {
     double cosphi, sinphi;
     int secant;
-    struct pj_opaque *Q = pj_calloc(1, sizeof (struct pj_opaque));
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc(1, sizeof (struct pj_opaque)));
 
-    if (0 == Q)
+    if (nullptr == Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_lcca.c b/src/projections/lcca.cpp
index f0f256b1..70b5dff9 100644
--- a/src/PJ_lcca.c
+++ b/src/projections/lcca.cpp
@@ -59,11 +59,13 @@ PROJ_HEAD(lcca, "Lambert Conformal Conic Alternative")
 #define MAX_ITER 10
 #define DEL_TOL 1e-12
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double *en;
     double r0, l, M0;
     double C;
 };
+} // anonymous namespace
 
 
 static double fS(double S, double C) {        /* func to compute dr */
@@ -80,7 +82,7 @@ static double fSp(double S, double C) {       /* deriv of fs */
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double S, r, dr;
 
     S = pj_mlfn(lp.phi, sin(lp.phi), cos(lp.phi), Q->en) - Q->M0;
@@ -94,7 +96,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double theta, dr, S, dif;
     int i;
 
@@ -118,22 +120,22 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 }
 
 
-static void *destructor (PJ *P, int errlev) {
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->en);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
     return pj_default_destructor (P, errlev);
 }
 
 
 PJ *PROJECTION(lcca) {
     double s2p0, N0, R0, tan0;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_loxim.c b/src/projections/loxim.cpp
index 512bfc23..f68e844a 100644
--- a/src/PJ_loxim.c
+++ b/src/projections/loxim.cpp
@@ -10,16 +10,18 @@ PROJ_HEAD(loxim, "Loximuthal") "\n\tPCyl Sph";
 
 #define EPS 1e-8
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double phi1;
     double cosphi1;
     double tanphi1;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     xy.y = lp.phi - Q->phi1;
     if (fabs(xy.y) < EPS)
@@ -37,7 +39,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     lp.phi = xy.y + Q->phi1;
     if (fabs(xy.y) < EPS) {
@@ -54,8 +56,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(loxim) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_lsat.c b/src/projections/lsat.cpp
index 810a1cba..a0eca1bd 100644
--- a/src/PJ_lsat.c
+++ b/src/projections/lsat.cpp
@@ -12,13 +12,15 @@ PROJ_HEAD(lsat, "Space oblique for LANDSAT")
 
 #define TOL 1e-7
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double a2, a4, b, c1, c3;
     double q, t, u, w, p22, sa, ca, xj, rlm, rlm2;
 };
+} // anonymous namespace
 
 static void seraz0(double lam, double mult, PJ *P) {
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double sdsq, h, s, fc, sd, sq, d__1 = 0;
 
     lam *= DEG_TO_RAD;
@@ -44,7 +46,7 @@ static void seraz0(double lam, double mult, PJ *P) {
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     int l, nn;
     double lamt = 0.0, xlam, sdsq, c, d, s, lamdp = 0.0, phidp, lampp, tanph;
     double lamtp, cl, sd, sp, sav, tanphi;
@@ -107,7 +109,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     int nn;
     double lamt, sdsq, s, lamdp, phidp, sppsq, dd, sd, sl, fac, scl, sav, spp;
 
@@ -153,8 +155,8 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 PJ *PROJECTION(lsat) {
     int land, path;
     double lam, alf, esc, ess;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_mbt_fps.c b/src/projections/mbt_fps.cpp
index 66ed9458..66ed9458 100644
--- a/src/PJ_mbt_fps.c
+++ b/src/projections/mbt_fps.cpp
diff --git a/src/PJ_mbtfpp.c b/src/projections/mbtfpp.cpp
index 276a43eb..276a43eb 100644
--- a/src/PJ_mbtfpp.c
+++ b/src/projections/mbtfpp.cpp
diff --git a/src/PJ_mbtfpq.c b/src/projections/mbtfpq.cpp
index b7c0eb16..b7c0eb16 100644
--- a/src/PJ_mbtfpq.c
+++ b/src/projections/mbtfpq.cpp
diff --git a/src/PJ_merc.c b/src/projections/merc.cpp
index 1998234e..1998234e 100644
--- a/src/PJ_merc.c
+++ b/src/projections/merc.cpp
diff --git a/src/PJ_mill.c b/src/projections/mill.cpp
index 3ea9636f..3ea9636f 100644
--- a/src/PJ_mill.c
+++ b/src/projections/mill.cpp
diff --git a/src/PJ_misrsom.c b/src/projections/misrsom.cpp
index 0308fc42..c84b96e3 100644
--- a/src/PJ_misrsom.c
+++ b/src/projections/misrsom.cpp
@@ -33,13 +33,15 @@ PROJ_HEAD(misrsom, "Space oblique for MISR")
 
 #define TOL 1e-7
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double a2, a4, b, c1, c3;
     double q, t, u, w, p22, sa, ca, xj, rlm, rlm2;
 };
+} // anonymous namespace
 
 static void seraz0(double lam, double mult, PJ *P) {
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double sdsq, h, s, fc, sd, sq, d__1;
 
     lam *= DEG_TO_RAD;
@@ -62,7 +64,7 @@ static void seraz0(double lam, double mult, PJ *P) {
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     int l, nn;
     double lamt = 0.0, xlam, sdsq, c, d, s, lamdp = 0.0, phidp, lampp, tanph;
     double lamtp, cl, sd, sp, sav, tanphi;
@@ -123,7 +125,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     int nn;
     double lamt, sdsq, s, lamdp, phidp, sppsq, dd, sd, sl, fac, scl, sav, spp;
 
@@ -170,8 +172,8 @@ PJ *PROJECTION(misrsom) {
     int path;
     double lam, alf, esc, ess;
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_mod_ster.c b/src/projections/mod_ster.cpp
index 5e6ce136..7c4f363b 100644
--- a/src/PJ_mod_ster.c
+++ b/src/projections/mod_ster.cpp
@@ -12,16 +12,18 @@ PROJ_HEAD(gs50, "Mod. Stereographic of 50 U.S.") "\n\tAzi(mod)";
 
 #define EPSLN 1e-12
 
+namespace { // anonymous namespace
 struct pj_opaque {
     const COMPLEX *zcoeff; \
     double  cchio, schio; \
     int     n;
 };
+} // anonymous namespace
 
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double sinlon, coslon, esphi, chi, schi, cchi, s;
     COMPLEX p;
 
@@ -45,7 +47,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     int nn;
     COMPLEX p, fxy, fpxy, dp;
     double den, rh = 0.0, z, sinz = 0.0, cosz = 0.0, chi, phi = 0.0, esphi;
@@ -101,7 +103,7 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 
 
 static PJ *setup(PJ *P) { /* general initialization */
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double esphi, chio;
 
     if (P->es != 0.0) {
@@ -127,8 +129,8 @@ PJ *PROJECTION(mil_os) {
         {0.019430, 0.}
     };
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -150,8 +152,8 @@ PJ *PROJECTION(lee_os) {
         {-0.0088162, -0.00617325}
     };
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -175,8 +177,8 @@ PJ *PROJECTION(gs48) {
         {0.075528,  0.}
     };
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -210,8 +212,8 @@ PJ *PROJECTION(alsk) {
         { .3660976, -.2937382}
     };
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -258,8 +260,8 @@ PJ *PROJECTION(gs50) {
         {-.0225161,  .0853673}
     };
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_moll.c b/src/projections/moll.cpp
index 4ac73841..c877a1bb 100644
--- a/src/PJ_moll.c
+++ b/src/projections/moll.cpp
@@ -12,14 +12,16 @@ PROJ_HEAD(wag5, "Wagner V") "\n\tPCyl, Sph";
 #define MAX_ITER    10
 #define LOOP_TOL    1e-7
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  C_x, C_y, C_p;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double k, V;
     int i;
 
@@ -42,7 +44,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     lp.phi = aasin(P->ctx, xy.y / Q->C_y);
     lp.lam = xy.x / (Q->C_x * cos(lp.phi));
         if (fabs(lp.lam) < M_PI) {
@@ -56,7 +58,7 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 static PJ * setup(PJ *P, double p) {
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double r, sp, p2 = p + p;
 
     P->es = 0;
@@ -74,8 +76,8 @@ static PJ * setup(PJ *P, double p) {
 
 
 PJ *PROJECTION(moll) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -84,8 +86,8 @@ PJ *PROJECTION(moll) {
 
 
 PJ *PROJECTION(wag4) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -93,8 +95,8 @@ PJ *PROJECTION(wag4) {
 }
 
 PJ *PROJECTION(wag5) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_natearth.c b/src/projections/natearth.cpp
index 27a6b137..27a6b137 100644
--- a/src/PJ_natearth.c
+++ b/src/projections/natearth.cpp
diff --git a/src/PJ_natearth2.c b/src/projections/natearth2.cpp
index f6aba671..f6aba671 100644
--- a/src/PJ_natearth2.c
+++ b/src/projections/natearth2.cpp
diff --git a/src/PJ_nell.c b/src/projections/nell.cpp
index 2a7ea32c..2a7ea32c 100644
--- a/src/PJ_nell.c
+++ b/src/projections/nell.cpp
diff --git a/src/PJ_nell_h.c b/src/projections/nell_h.cpp
index 28c3ace7..28c3ace7 100644
--- a/src/PJ_nell_h.c
+++ b/src/projections/nell_h.cpp
diff --git a/src/PJ_nocol.c b/src/projections/nicol.cpp
index 541d08b2..541d08b2 100644
--- a/src/PJ_nocol.c
+++ b/src/projections/nicol.cpp
diff --git a/src/PJ_nsper.c b/src/projections/nsper.cpp
index 223cd75b..f93010f8 100644
--- a/src/PJ_nsper.c
+++ b/src/projections/nsper.cpp
@@ -4,13 +4,16 @@
 #include "projects.h"
 #include "proj_math.h"
 
+namespace { // anonymous namespace
 enum Mode {
     N_POLE = 0,
     S_POLE = 1,
     EQUIT  = 2,
     OBLIQ  = 3
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  height;
     double  sinph0;
@@ -27,6 +30,7 @@ struct pj_opaque {
     enum Mode mode;
     int     tilt;
 };
+} // anonymous namespace
 
 PROJ_HEAD(nsper, "Near-sided perspective") "\n\tAzi, Sph\n\th=";
 PROJ_HEAD(tpers, "Tilted perspective") "\n\tAzi, Sph\n\ttilt= azi= h=";
@@ -36,7 +40,7 @@ PROJ_HEAD(tpers, "Tilted perspective") "\n\tAzi, Sph\n\ttilt= azi= h=";
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  coslam, cosphi, sinphi;
 
     sinphi = sin(lp.phi);
@@ -91,7 +95,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  rh, cosz, sinz;
 
     if (Q->tilt) {
@@ -140,7 +144,7 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 static PJ *setup(PJ *P) {
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     if ((Q->height = pj_param(P->ctx, P->params, "dh").f) <= 0.)
         return pj_default_destructor(P, PJD_ERR_H_LESS_THAN_ZERO);
@@ -168,8 +172,8 @@ static PJ *setup(PJ *P) {
 
 
 PJ *PROJECTION(nsper) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -182,8 +186,8 @@ PJ *PROJECTION(nsper) {
 PJ *PROJECTION(tpers) {
     double omega, gamma;
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_nzmg.c b/src/projections/nzmg.cpp
index bf0862fb..bf0862fb 100644
--- a/src/PJ_nzmg.c
+++ b/src/projections/nzmg.cpp
diff --git a/src/PJ_ob_tran.c b/src/projections/ob_tran.cpp
index f5a05cf9..d34059a9 100644
--- a/src/PJ_ob_tran.c
+++ b/src/projections/ob_tran.cpp
@@ -7,11 +7,13 @@
 #include "proj.h"
 #include "projects.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     struct PJconsts *link;
     double  lamp;
     double  cphip, sphip;
 };
+} // anonymous namespace
 
 PROJ_HEAD(ob_tran, "General Oblique Transformation") "\n\tMisc Sph"
 "\n\to_proj= plus parameters for projection"
@@ -23,7 +25,7 @@ PROJ_HEAD(ob_tran, "General Oblique Transformation") "\n\tMisc Sph"
 
 
 static XY o_forward(LP lp, PJ *P) {             /* spheroid */
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double coslam, sinphi, cosphi;
 
     coslam = cos(lp.lam);
@@ -38,7 +40,7 @@ static XY o_forward(LP lp, PJ *P) {             /* spheroid */
 
 
 static XY t_forward(LP lp, PJ *P) {             /* spheroid */
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double cosphi, coslam;
 
     cosphi = cos(lp.phi);
@@ -52,7 +54,7 @@ static XY t_forward(LP lp, PJ *P) {             /* spheroid */
 
 static LP o_inverse(XY xy, PJ *P) {             /* spheroid */
 
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double coslam, sinphi, cosphi;
 
     LP lp = Q->link->inv(xy, Q->link);
@@ -70,7 +72,7 @@ static LP o_inverse(XY xy, PJ *P) {             /* spheroid */
 
 static LP t_inverse(XY xy, PJ *P) {             /* spheroid */
 
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double cosphi, t;
 
     LP lp = Q->link->inv(xy, Q->link);
@@ -84,14 +86,14 @@ static LP t_inverse(XY xy, PJ *P) {             /* spheroid */
 }
 
 
-static void *destructor(PJ *P, int errlev) {
-    if (0==P)
-        return 0;
-    if (0==P->opaque)
+static PJ *destructor(PJ *P, int errlev) {
+    if (nullptr==P)
+        return nullptr;
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    if (P->opaque->link)
-        P->opaque->link->destructor (P->opaque->link, errlev);
+    if (static_cast<struct pj_opaque*>(P->opaque)->link)
+        static_cast<struct pj_opaque*>(P->opaque)->link->destructor (static_cast<struct pj_opaque*>(P->opaque)->link, errlev);
 
     return pj_default_destructor(P, errlev);
 }
@@ -120,7 +122,7 @@ typedef struct {int argc; char **argv;} ARGS;
 /* count the number of args in the linked list <params> */
 static size_t paralist_params_argc (paralist *params) {
     size_t argc = 0;
-    for (; params != 0; params = params->next)
+    for (; params != nullptr; params = params->next)
         argc++;
     return argc;
 }
@@ -129,18 +131,18 @@ static size_t paralist_params_argc (paralist *params) {
 /* turn paralist into argc/argv style argument list */
 static ARGS ob_tran_target_params (paralist *params) {
     int i = 0;
-    ARGS args = {0, 0};
+    ARGS args = {0, nullptr};
     size_t argc = paralist_params_argc (params);
     if (argc < 2)
         return args;
 
     /* all args except the proj_ob_tran */
-    args.argv = pj_calloc (argc - 1, sizeof (char *));
-    if (0==args.argv)
+    args.argv = static_cast<char**>(pj_calloc (argc - 1, sizeof (char *)));
+    if (nullptr==args.argv)
         return args;
 
     /* Copy all args *except* the proj=ob_tran arg to the argv array */
-    for (i = 0;  params != 0;  params = params->next) {
+    for (i = 0;  params != nullptr;  params = params->next) {
         if (0==strcmp (params->param, "proj=ob_tran"))
             continue;
         args.argv[i++] = params->param;
@@ -166,8 +168,8 @@ PJ *PROJECTION(ob_tran) {
     ARGS args;
     PJ *R; /* projection to rotate */
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return destructor(P, ENOMEM);
 
     P->opaque = Q;
@@ -186,7 +188,7 @@ PJ *PROJECTION(ob_tran) {
     R = pj_init_ctx (pj_get_ctx(P), args.argc, args.argv);
     pj_dealloc (args.argv);
 
-    if (0==R)
+    if (nullptr==R)
         return destructor (P, PJD_ERR_UNKNOWN_PROJECTION_ID);
     Q->link = R;
 
@@ -226,11 +228,11 @@ PJ *PROJECTION(ob_tran) {
     if (fabs(phip) > TOL) { /* oblique */
         Q->cphip = cos(phip);
         Q->sphip = sin(phip);
-        P->fwd = Q->link->fwd ? o_forward : 0;
-        P->inv = Q->link->inv ? o_inverse : 0;
+        P->fwd = Q->link->fwd ? o_forward : nullptr;
+        P->inv = Q->link->inv ? o_inverse : nullptr;
     } else { /* transverse */
-        P->fwd = Q->link->fwd ? t_forward : 0;
-        P->inv = Q->link->inv ? t_inverse : 0;
+        P->fwd = Q->link->fwd ? t_forward : nullptr;
+        P->inv = Q->link->inv ? t_inverse : nullptr;
     }
 
     /* Support some rather speculative test cases, where the rotated projection */
diff --git a/src/PJ_ocea.c b/src/projections/ocea.cpp
index 7a9353a6..0576ace7 100644
--- a/src/PJ_ocea.c
+++ b/src/projections/ocea.cpp
@@ -8,6 +8,7 @@
 PROJ_HEAD(ocea, "Oblique Cylindrical Equal Area") "\n\tCyl, Sph"
     "lonc= alpha= or\n\tlat_1= lat_2= lon_1= lon_2=";
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  rok;
     double  rtk;
@@ -16,11 +17,12 @@ struct pj_opaque {
     double  singam;
     double  cosgam;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double t;
     xy.y = sin(lp.lam);
     t = cos(lp.lam);
@@ -35,7 +37,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double t, s;
 
     xy.y /= Q->rok;
@@ -51,8 +53,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 PJ *PROJECTION(ocea) {
     double phi_0=0.0, phi_1, phi_2, lam_1, lam_2, lonz, alpha;
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_oea.c b/src/projections/oea.cpp
index 2bfeffa8..0c401b2f 100644
--- a/src/PJ_oea.c
+++ b/src/projections/oea.cpp
@@ -6,17 +6,19 @@
 
 PROJ_HEAD(oea, "Oblated Equal Area") "\n\tMisc Sph\n\tn= m= theta=";
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  theta;
     double  m, n;
     double  two_r_m, two_r_n, rm, rn, hm, hn;
     double  cp0, sp0;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double Az, M, N, cp, sp, cl, shz;
 
     cp = cos(lp.phi);
@@ -35,7 +37,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double N, M, xp, yp, z, Az, cz, sz, cAz;
 
     N = Q->hn * aasin(P->ctx,xy.y * Q->rn);
@@ -57,8 +59,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(oea) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_omerc.c b/src/projections/omerc.cpp
index 70c12e27..ead07128 100644
--- a/src/PJ_omerc.c
+++ b/src/projections/omerc.cpp
@@ -33,11 +33,13 @@ PROJ_HEAD(omerc, "Oblique Mercator")
     "\n\tCyl, Sph&Ell no_rot\n\t"
     "alpha= [gamma=] [no_off] lonc= or\n\t lon_1= lat_1= lon_2= lat_2=";
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  A, B, E, AB, ArB, BrA, rB, singam, cosgam, sinrot, cosrot;
     double  v_pole_n, v_pole_s, u_0;
     int no_rot;
 };
+} // anonymous namespace
 
 #define TOL 1.e-7
 #define EPS 1.e-10
@@ -45,7 +47,7 @@ struct pj_opaque {
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double S, T, U, V, W, temp, u, v;
 
     if (fabs(fabs(lp.phi) - M_HALFPI) > EPS) {
@@ -84,7 +86,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  u, v, Qp, Sp, Tp, Vp, Up;
 
     if (Q->no_rot) {
@@ -120,8 +122,8 @@ PJ *PROJECTION(omerc) {
         gamma0, lamc=0, lam1=0, lam2=0, phi1=0, phi2=0, alpha_c=0;
     int alp, gam, no_off = 0;
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_ortho.c b/src/projections/ortho.cpp
index d442aa8a..6ea55248 100644
--- a/src/PJ_ortho.c
+++ b/src/projections/ortho.cpp
@@ -7,18 +7,22 @@
 
 PROJ_HEAD(ortho, "Orthographic") "\n\tAzi, Sph";
 
+namespace { // anonymous namespace
 enum Mode {
     N_POLE = 0,
     S_POLE = 1,
     EQUIT  = 2,
     OBLIQ  = 3
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  sinph0;
     double  cosph0;
     enum Mode mode;
 };
+} // anonymous namespace
 
 #define EPS10 1.e-10
 
@@ -31,7 +35,7 @@ static XY forward_error(PJ *P, LP lp, XY xy) {
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy;
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  coslam, cosphi, sinphi;
 
     xy.x = HUGE_VAL; xy.y = HUGE_VAL;
@@ -65,7 +69,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp;
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  rh, cosc, sinc;
 
     lp.lam = HUGE_VAL; lp.phi = HUGE_VAL;
@@ -117,8 +121,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(ortho) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_patterson.c b/src/projections/patterson.cpp
index 0d19414e..0d19414e 100644
--- a/src/PJ_patterson.c
+++ b/src/projections/patterson.cpp
diff --git a/src/PJ_poly.c b/src/projections/poly.cpp
index b5f78fdf..a970fdb1 100644
--- a/src/PJ_poly.c
+++ b/src/projections/poly.cpp
@@ -9,10 +9,12 @@
 PROJ_HEAD(poly, "Polyconic (American)")
     "\n\tConic, Sph&Ell";
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double ml0; \
     double *en;
 };
+} // anonymous namespace
 
 #define TOL 1e-10
 #define CONV    1e-10
@@ -23,7 +25,7 @@ struct pj_opaque {
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  ms, sp, cp;
 
     if (fabs(lp.phi) <= TOL) {
@@ -42,7 +44,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  cot, E;
 
     if (fabs(lp.phi) <= TOL) {
@@ -60,7 +62,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     xy.y += Q->ml0;
     if (fabs(xy.y) <= TOL) {
@@ -131,23 +133,23 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 }
 
 
-static void *destructor(PJ *P, int errlev) {
-    if (0==P)
-        return 0;
+static PJ *destructor(PJ *P, int errlev) {
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    if (P->opaque->en)
-        pj_dealloc (P->opaque->en);
+    if (static_cast<struct pj_opaque*>(P->opaque)->en)
+        pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
 
     return pj_default_destructor(P, errlev);
 }
 
 
 PJ *PROJECTION(poly) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
 
     P->opaque = Q;
diff --git a/src/PJ_putp2.c b/src/projections/putp2.cpp
index d7a847c8..d7a847c8 100644
--- a/src/PJ_putp2.c
+++ b/src/projections/putp2.cpp
diff --git a/src/PJ_putp3.c b/src/projections/putp3.cpp
index 695ea877..98bb2ff0 100644
--- a/src/PJ_putp3.c
+++ b/src/projections/putp3.cpp
@@ -2,9 +2,11 @@
 #include <errno.h>
 #include "projects.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  A;
 };
+} // anonymous namespace
 
 PROJ_HEAD(putp3, "Putnins P3") "\n\tPCyl, Sph";
 PROJ_HEAD(putp3p, "Putnins P3'") "\n\tPCyl, Sph";
@@ -16,7 +18,7 @@ PROJ_HEAD(putp3p, "Putnins P3'") "\n\tPCyl, Sph";
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
 
-    xy.x = C * lp.lam * (1. - P->opaque->A * lp.phi * lp.phi);
+    xy.x = C * lp.lam * (1. - static_cast<struct pj_opaque*>(P->opaque)->A * lp.phi * lp.phi);
     xy.y = C * lp.phi;
 
     return xy;
@@ -27,15 +29,15 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
 
     lp.phi = xy.y / C;
-    lp.lam = xy.x / (C * (1. - P->opaque->A * lp.phi * lp.phi));
+    lp.lam = xy.x / (C * (1. - static_cast<struct pj_opaque*>(P->opaque)->A * lp.phi * lp.phi));
 
     return lp;
 }
 
 
 PJ *PROJECTION(putp3) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -49,8 +51,8 @@ PJ *PROJECTION(putp3) {
 }
 
 PJ *PROJECTION(putp3p) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_putp4p.c b/src/projections/putp4p.cpp
index 6448dc19..608fc76e 100644
--- a/src/PJ_putp4p.c
+++ b/src/projections/putp4p.cpp
@@ -5,9 +5,11 @@
 
 #include "projects.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double C_x, C_y;
 };
+} // anonymous namespace
 
 PROJ_HEAD(putp4p, "Putnins P4'") "\n\tPCyl, Sph";
 PROJ_HEAD(weren, "Werenskiold I") "\n\tPCyl, Sph";
@@ -15,7 +17,7 @@ PROJ_HEAD(weren, "Werenskiold I") "\n\tPCyl, Sph";
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     lp.phi = aasin(P->ctx,0.883883476 * sin(lp.phi));
     xy.x = Q->C_x * lp.lam * cos(lp.phi);
@@ -28,7 +30,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     lp.phi = aasin(P->ctx,xy.y / Q->C_y);
     lp.lam = xy.x * cos(lp.phi) / Q->C_x;
@@ -41,8 +43,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(putp4p) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -58,8 +60,8 @@ PJ *PROJECTION(putp4p) {
 
 
 PJ *PROJECTION(weren) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_putp5.c b/src/projections/putp5.cpp
index 96b0670d..79e2ad15 100644
--- a/src/PJ_putp5.c
+++ b/src/projections/putp5.cpp
@@ -5,9 +5,11 @@
 
 #include "projects.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  A, B;
 };
+} // anonymous namespace
 
 PROJ_HEAD(putp5, "Putnins P5") "\n\tPCyl, Sph";
 PROJ_HEAD(putp5p, "Putnins P5'") "\n\tPCyl, Sph";
@@ -18,7 +20,7 @@ PROJ_HEAD(putp5p, "Putnins P5'") "\n\tPCyl, Sph";
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     xy.x = C * lp.lam * (Q->A - Q->B * sqrt(1. + D * lp.phi * lp.phi));
     xy.y = C * lp.phi;
@@ -29,7 +31,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     lp.phi = xy.y / C;
     lp.lam = xy.x / (C * (Q->A - Q->B * sqrt(1. + D * lp.phi * lp.phi)));
@@ -40,8 +42,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(putp5) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -57,8 +59,8 @@ PJ *PROJECTION(putp5) {
 
 
 PJ *PROJECTION(putp5p) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_putp6.c b/src/projections/putp6.cpp
index fa9290b4..1186b18b 100644
--- a/src/PJ_putp6.c
+++ b/src/projections/putp6.cpp
@@ -5,9 +5,11 @@
 
 #include "projects.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double C_x, C_y, A, B, D;
 };
+} // anonymous namespace
 
 PROJ_HEAD(putp6, "Putnins P6") "\n\tPCyl, Sph";
 PROJ_HEAD(putp6p, "Putnins P6'") "\n\tPCyl, Sph";
@@ -19,7 +21,7 @@ PROJ_HEAD(putp6p, "Putnins P6'") "\n\tPCyl, Sph";
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double p, r, V;
     int i;
 
@@ -43,7 +45,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double r;
 
     lp.phi = xy.y / Q->C_y;
@@ -56,8 +58,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 
 PJ *PROJECTION(putp6) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
@@ -76,8 +78,8 @@ PJ *PROJECTION(putp6) {
 
 
 PJ *PROJECTION(putp6p) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_qsc.c b/src/projections/qsc.cpp
index 3b8b7fe2..b50a7c95 100644
--- a/src/PJ_qsc.c
+++ b/src/projections/qsc.cpp
@@ -46,6 +46,7 @@
 #include "projects.h"
 
 /* The six cube faces. */
+namespace { // anonymous namespace
 enum Face {
     FACE_FRONT  = 0,
     FACE_RIGHT  = 1,
@@ -54,7 +55,9 @@ enum Face {
     FACE_TOP    = 4,
     FACE_BOTTOM = 5
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque {
         enum Face face;
         double a_squared;
@@ -62,18 +65,21 @@ struct pj_opaque {
         double one_minus_f;
         double one_minus_f_squared;
 };
+} // anonymous namespace
 PROJ_HEAD(qsc, "Quadrilateralized Spherical Cube") "\n\tAzi, Sph";
 
 #define EPS10 1.e-10
 
 /* The four areas on a cube face. AREA_0 is the area of definition,
  * the other three areas are counted counterclockwise. */
+namespace { // anonymous namespace
 enum Area {
     AREA_0 = 0,
     AREA_1 = 1,
     AREA_2 = 2,
     AREA_3 = 3
 };
+} // anonymous namespace
 
 /* Helper function for forward projection: compute the theta angle
  * and determine the area number. */
@@ -114,7 +120,7 @@ static double qsc_shift_lon_origin(double lon, double offset) {
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double lat, lon;
     double theta, phi;
     double t, mu; /* nu; */
@@ -230,7 +236,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double mu, nu, cosmu, tannu;
     double tantheta, theta, cosphi, phi;
     double t;
@@ -370,8 +376,8 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 
 
 PJ *PROJECTION(qsc) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_robin.c b/src/projections/robin.cpp
index 19bdc2dc..987977ae 100644
--- a/src/PJ_robin.c
+++ b/src/projections/robin.cpp
@@ -18,9 +18,11 @@ http://article.gmane.org/gmane.comp.gis.proj-4.devel/6039
 http://trac.osgeo.org/proj/ticket/113
 */
 
+namespace { // anonymous namespace
 struct COEFS {
     float c0, c1, c2, c3;
 };
+} // anonymous namespace
 
 static const struct COEFS X[] = {
     {1.0f, 2.2199e-17f, -7.15515e-05f, 3.1103e-06f},
diff --git a/src/proj_rouss.c b/src/projections/rouss.cpp
index 0e0f9982..3b4428bc 100644
--- a/src/proj_rouss.c
+++ b/src/projections/rouss.cpp
@@ -31,6 +31,7 @@
 #include "proj.h"
 #include "projects.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double s0;
     double A1, A2, A3, A4, A5, A6;
@@ -39,12 +40,13 @@ struct pj_opaque {
     double D1, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11;
     void *en;
 };
+} // anonymous namespace
 PROJ_HEAD(rouss, "Roussilhe Stereographic") "\n\tAzi, Ell";
 
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double s, al, cp, sp, al2, s2;
 
     cp = cos(lp.phi);
@@ -65,7 +67,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double s, al, x = xy.x / P->k0, y = xy.y / P->k0, x2, y2;;
 
     x2 = x * x;
@@ -83,15 +85,15 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 }
 
 
-static void *destructor (PJ *P, int errlev) {
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    if (P->opaque->en)
-        pj_dealloc (P->opaque->en);
+    if (static_cast<struct pj_opaque*>(P->opaque)->en)
+        pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
 
     return pj_default_destructor (P, ENOMEM);
 }
@@ -100,8 +102,8 @@ static void *destructor (PJ *P, int errlev) {
 PJ *PROJECTION(rouss) {
     double N0, es2, t, t2, R_R0_2, R_R0_4;
 
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_rpoly.c b/src/projections/rpoly.cpp
index 03c2b161..a34f6171 100644
--- a/src/PJ_rpoly.c
+++ b/src/projections/rpoly.cpp
@@ -5,12 +5,14 @@
 
 #include "projects.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  phi1;
     double  fxa;
     double  fxb;
     int     mode;
 };
+} // anonymous namespace
 
 PROJ_HEAD(rpoly, "Rectangular Polyconic")
     "\n\tConic, Sph, no inv\n\tlat_ts=";
@@ -19,7 +21,7 @@ PROJ_HEAD(rpoly, "Rectangular Polyconic")
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double fa;
 
     if (Q->mode)
@@ -40,8 +42,8 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 
 PJ *PROJECTION(rpoly) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_sch.c b/src/projections/sch.cpp
index 64e5cdb8..5a2f944b 100644
--- a/src/PJ_sch.c
+++ b/src/projections/sch.cpp
@@ -39,6 +39,7 @@
 #include "projects.h"
 #include "geocent.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double plat; /*Peg Latitude */
     double plon; /*Peg Longitude*/
@@ -50,12 +51,13 @@ struct pj_opaque {
     GeocentricInfo sph;
     GeocentricInfo elp_0;
 };
+} // anonymous namespace
 
 PROJ_HEAD(sch, "Spherical Cross-track Height") "\n\tMisc\n\tplat_0= plon_0= phdg_0= [h_0=]";
 
 static LPZ inverse3d(XYZ xyz, PJ *P) {
     LPZ lpz = {0.0, 0.0, 0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double temp[3];
     double pxyz[3];
 
@@ -93,7 +95,7 @@ static LPZ inverse3d(XYZ xyz, PJ *P) {
 
 static XYZ forward3d(LPZ lpz, PJ *P) {
     XYZ xyz = {0.0, 0.0, 0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double temp[3];
     double pxyz[3];
 
@@ -131,7 +133,7 @@ static XYZ forward3d(LPZ lpz, PJ *P) {
 
 
 static PJ *setup(PJ *P) { /* general initialization */
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double reast, rnorth;
     double chdg, shdg;
     double clt, slt;
@@ -192,8 +194,8 @@ static PJ *setup(PJ *P) { /* general initialization */
 
 
 PJ *PROJECTION(sch) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_sconics.c b/src/projections/sconics.cpp
index ce044c24..1d19a13d 100644
--- a/src/PJ_sconics.c
+++ b/src/projections/sconics.cpp
@@ -5,6 +5,7 @@
 #include "proj_math.h"
 
 
+namespace { // anonymous namespace
 enum Type {
     EULER  = 0,
     MURD1  = 1,
@@ -14,7 +15,9 @@ enum Type {
     TISSOT = 5,
     VITK1  = 6
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  n;
     double  rho_c;
@@ -23,6 +26,7 @@ struct pj_opaque {
     double  c1, c2;
     enum Type type;
 };
+} // anonymous namespace
 
 
 #define EPS10   1.e-10
@@ -51,8 +55,8 @@ static int phi12(PJ *P, double *del) {
         p1 = pj_param(P->ctx, P->params, "rlat_1").f;
         p2 = pj_param(P->ctx, P->params, "rlat_2").f;
         *del = 0.5 * (p2 - p1);
-        P->opaque->sig = 0.5 * (p2 + p1);
-        err = (fabs(*del) < EPS || fabs(P->opaque->sig) < EPS) ? PJD_ERR_ABS_LAT1_EQ_ABS_LAT2 : 0;
+        static_cast<struct pj_opaque*>(P->opaque)->sig = 0.5 * (p2 + p1);
+        err = (fabs(*del) < EPS || fabs(static_cast<struct pj_opaque*>(P->opaque)->sig) < EPS) ? PJD_ERR_ABS_LAT1_EQ_ABS_LAT2 : 0;
     }
     return err;
 }
@@ -60,7 +64,7 @@ static int phi12(PJ *P, double *del) {
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0, 0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double rho;
 
     switch (Q->type) {
@@ -83,7 +87,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {  /* Spheroidal, (and ellipsoidal?) inverse */
     LP lp = {0.0, 0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double rho;
 
     rho = hypot (xy.x,  xy.y = Q->rho_0 - xy.y);
@@ -112,8 +116,8 @@ static LP s_inverse (XY xy, PJ *P) {  /* Spheroidal, (and ellipsoidal?) inverse
 static PJ *setup(PJ *P, enum Type type) {
     double del, cs;
     int err;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
     Q->type = type;
diff --git a/src/PJ_somerc.c b/src/projections/somerc.cpp
index c6c3ff21..15d2e765 100644
--- a/src/PJ_somerc.c
+++ b/src/projections/somerc.cpp
@@ -8,9 +8,11 @@
 
 PROJ_HEAD(somerc, "Swiss. Obl. Mercator") "\n\tCyl, Ell\n\tFor CH1903";
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double K, c, hlf_e, kR, cosp0, sinp0;
 };
+} // anonymous namespace
 
 #define EPS 1.e-10
 #define NITER 6
@@ -19,7 +21,7 @@ struct pj_opaque {
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0, 0.0};
     double phip, lamp, phipp, lampp, sp, cp;
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     sp = P->e * sin (lp.phi);
     phip = 2.* atan ( exp ( Q->c * (
@@ -37,7 +39,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double phip, lamp, phipp, lampp, cp, esp, con, delp;
     int i;
 
@@ -69,8 +71,8 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 
 PJ *PROJECTION(somerc) {
     double cp, phip0, sp;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_stere.c b/src/projections/stere.cpp
index 82fd5c07..1502b2a6 100644
--- a/src/PJ_stere.c
+++ b/src/projections/stere.cpp
@@ -8,13 +8,16 @@ PROJ_HEAD(stere, "Stereographic") "\n\tAzi, Sph&Ell\n\tlat_ts=";
 PROJ_HEAD(ups, "Universal Polar Stereographic") "\n\tAzi, Sph&Ell\n\tsouth";
 
 
+namespace { // anonymous namespace
 enum Mode {
     S_POLE = 0,
     N_POLE = 1,
     OBLIQ  = 2,
     EQUIT  = 3
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double phits;
     double sinX1;
@@ -22,9 +25,10 @@ struct pj_opaque {
     double akm1;
     enum Mode mode;
 };
+} // anonymous namespace
 
-#define sinph0  P->opaque->sinX1
-#define cosph0  P->opaque->cosX1
+#define sinph0  static_cast<struct pj_opaque*>(P->opaque)->sinX1
+#define cosph0  static_cast<struct pj_opaque*>(P->opaque)->cosX1
 #define EPS10   1.e-10
 #define TOL 1.e-8
 #define NITER   8
@@ -39,7 +43,7 @@ static double ssfn_ (double phit, double sinphi, double eccen) {
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double coslam, sinlam, sinX = 0.0, cosX = 0.0, X, A = 0.0, sinphi;
 
     coslam = cos (lp.lam);
@@ -87,7 +91,7 @@ xmul:
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  sinphi, cosphi, coslam, sinlam;
 
     sinphi = sin(lp.phi);
@@ -129,7 +133,7 @@ oblcon:
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double cosphi, sinphi, tp=0.0, phi_l=0.0, rho, halfe=0.0, halfpi=0.0;
     int i;
 
@@ -179,7 +183,7 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double  c, rh, sinc, cosc;
 
     sinc = sin (c = 2. * atan ((rh = hypot (xy.x, xy.y)) / Q->akm1));
@@ -220,7 +224,7 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 static PJ *setup(PJ *P) {                   /* general initialization */
     double t;
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 
     if (fabs ((t = fabs (P->phi0)) - M_HALFPI) < EPS10)
         Q->mode = P->phi0 < 0. ? S_POLE : N_POLE;
@@ -281,8 +285,8 @@ static PJ *setup(PJ *P) {                   /* general initialization */
 
 
 PJ *PROJECTION(stere) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -294,8 +298,8 @@ PJ *PROJECTION(stere) {
 
 
 PJ *PROJECTION(ups) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_sterea.c b/src/projections/sterea.cpp
index eb4c9f2c..bb498068 100644
--- a/src/PJ_sterea.c
+++ b/src/projections/sterea.cpp
@@ -29,12 +29,14 @@
 #include "proj_math.h"
 
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double phic0;
     double cosc0, sinc0;
     double R2;
     void *en;
 };
+} // anonymous namespace
 
 
 PROJ_HEAD(sterea, "Oblique Stereographic Alternative") "\n\tAzimuthal, Sph&Ell";
@@ -43,7 +45,7 @@ PROJ_HEAD(sterea, "Oblique Stereographic Alternative") "\n\tAzimuthal, Sph&Ell";
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double cosc, sinc, cosl, k;
 
     lp = pj_gauss(P->ctx, lp, Q->en);
@@ -59,7 +61,7 @@ static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double rho, c, sinc, cosc;
 
     xy.x /= P->k0;
@@ -78,28 +80,28 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
 }
 
 
-static void *destructor (PJ *P, int errlev) {
-    if (0==P)
-        return 0;
+static PJ *destructor (PJ *P, int errlev) {
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    pj_dealloc (P->opaque->en);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
     return pj_default_destructor (P, errlev);
 }
 
 
 PJ *PROJECTION(sterea) {
     double R;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
 
-    if (0==Q)
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
     Q->en = pj_gauss_ini(P->e, P->phi0, &(Q->phic0), &R);
-    if (0==Q->en)
+    if (nullptr==Q->en)
         return pj_default_destructor (P, ENOMEM);
 
     Q->sinc0 = sin (Q->phic0);
diff --git a/src/PJ_sts.c b/src/projections/sts.cpp
index 66094178..9f889611 100644
--- a/src/PJ_sts.c
+++ b/src/projections/sts.cpp
@@ -11,15 +11,17 @@ PROJ_HEAD(fouc,    "Foucaut")             "\n\tPCyl, Sph";
 PROJ_HEAD(mbt_s,   "McBryde-Thomas Flat-Polar Sine (No. 1)") "\n\tPCyl, Sph";
 
 
+namespace { // anonymous namespace
 struct pj_opaque {
 	double C_x, C_y, C_p;
 	int tan_mode;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 	double c;
 
 	xy.x = Q->C_x * lp.lam * cos(lp.phi);
@@ -39,7 +41,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
 	double c;
 
 	xy.y /= Q->C_y;
@@ -58,18 +60,18 @@ static PJ *setup(PJ *P, double p, double q, int mode) {
 	P->es  = 0.;
 	P->inv = s_inverse;
 	P->fwd = s_forward;
-	P->opaque->C_x = q / p;
-	P->opaque->C_y = p;
-	P->opaque->C_p = 1/ q;
-	P->opaque->tan_mode = mode;
+	static_cast<struct pj_opaque*>(P->opaque)->C_x = q / p;
+	static_cast<struct pj_opaque*>(P->opaque)->C_y = p;
+	static_cast<struct pj_opaque*>(P->opaque)->C_p = 1/ q;
+	static_cast<struct pj_opaque*>(P->opaque)->tan_mode = mode;
 	return P;
 }
 
 
 
 PJ *PROJECTION(fouc) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
     return setup(P, 2., 2., 1);
@@ -78,8 +80,8 @@ PJ *PROJECTION(fouc) {
 
 
 PJ *PROJECTION(kav5) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
@@ -89,8 +91,8 @@ PJ *PROJECTION(kav5) {
 
 
 PJ *PROJECTION(qua_aut) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
     return setup(P, 2., 2., 0);
@@ -99,8 +101,8 @@ PJ *PROJECTION(qua_aut) {
 
 
 PJ *PROJECTION(mbt_s) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
     return setup(P, 1.48875, 1.36509, 0);
diff --git a/src/PJ_tcc.c b/src/projections/tcc.cpp
index 60ded63e..64fdc182 100644
--- a/src/PJ_tcc.c
+++ b/src/projections/tcc.cpp
@@ -28,7 +28,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 PJ *PROJECTION(tcc) {
     P->es  = 0.;
     P->fwd = s_forward;
-    P->inv = 0;
+    P->inv = nullptr;
 
     return P;
 }
diff --git a/src/PJ_tcea.c b/src/projections/tcea.cpp
index d30f3df0..d30f3df0 100644
--- a/src/PJ_tcea.c
+++ b/src/projections/tcea.cpp
diff --git a/src/PJ_times.c b/src/projections/times.cpp
index e8b4499f..e8b4499f 100644
--- a/src/PJ_times.c
+++ b/src/projections/times.cpp
diff --git a/src/PJ_tmerc.c b/src/projections/tmerc.cpp
index 069cdc2c..5a2dacbd 100644
--- a/src/PJ_tmerc.c
+++ b/src/projections/tmerc.cpp
@@ -9,11 +9,13 @@
 PROJ_HEAD(tmerc, "Transverse Mercator") "\n\tCyl, Sph&Ell";
 
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  esp;
     double  ml0;
     double  *en;
 };
+} // anonymous namespace
 
 #define EPS10   1.e-10
 #define FC1 1.
@@ -28,7 +30,7 @@ struct pj_opaque {
 
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0, 0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double al, als, n, cosphi, sinphi, t;
 
     /*
@@ -93,7 +95,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
         return xy;
     }
 
-    xy.x = P->opaque->ml0 * log ((1. + b) / (1. - b));
+    xy.x = static_cast<struct pj_opaque*>(P->opaque)->ml0 * log ((1. + b) / (1. - b));
     xy.y = cosphi * cos (lp.lam) / sqrt (1. - b * b);
 
     b = fabs ( xy.y );
@@ -108,14 +110,14 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
     if (lp.phi < 0.)
         xy.y = -xy.y;
-    xy.y = P->opaque->esp * (xy.y - P->phi0);
+    xy.y = static_cast<struct pj_opaque*>(P->opaque)->esp * (xy.y - P->phi0);
     return xy;
 }
 
 
 static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double n, con, cosphi, d, ds, sinphi, t;
 
     lp.phi = pj_inv_mlfn(P->ctx, Q->ml0 + xy.y / P->k0, P->es, Q->en);
@@ -151,9 +153,9 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0, 0.0};
     double h, g;
 
-    h = exp(xy.x / P->opaque->esp);
+    h = exp(xy.x / static_cast<struct pj_opaque*>(P->opaque)->esp);
     g = .5 * (h - 1. / h);
-    h = cos (P->phi0 + xy.y / P->opaque->esp);
+    h = cos (P->phi0 + xy.y / static_cast<struct pj_opaque*>(P->opaque)->esp);
     lp.phi = asin(sqrt((1. - h * h) / (1. + g * g)));
 
     /* Make sure that phi is on the correct hemisphere when false northing is used */
@@ -164,20 +166,20 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 }
 
 
-static void *destructor(PJ *P, int errlev) {                       /* Destructor */
-    if (0==P)
-        return 0;
+static PJ *destructor(PJ *P, int errlev) {                       /* Destructor */
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor(P, errlev);
 
-    pj_dealloc (P->opaque->en);
+    pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
     return pj_default_destructor(P, errlev);
 }
 
 
 static PJ *setup(PJ *P) {                   /* general initialization */
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     if (P->es != 0.0) {
         if (!(Q->en = pj_enfn(P->es)))
             return pj_default_destructor(P, ENOMEM);
@@ -197,8 +199,8 @@ static PJ *setup(PJ *P) {                   /* general initialization */
 
 
 PJ *PROJECTION(tmerc) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
 
     P->opaque = Q;
diff --git a/src/PJ_tobmerc.c b/src/projections/tobmerc.cpp
index 9c939f0b..9c939f0b 100644
--- a/src/PJ_tobmerc.c
+++ b/src/projections/tobmerc.cpp
diff --git a/src/PJ_tpeqd.c b/src/projections/tpeqd.cpp
index 87877ec1..2720327a 100644
--- a/src/PJ_tpeqd.c
+++ b/src/projections/tpeqd.cpp
@@ -8,15 +8,17 @@
 PROJ_HEAD(tpeqd, "Two Point Equidistant")
     "\n\tMisc Sph\n\tlat_1= lon_1= lat_2= lon_2=";
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double cp1, sp1, cp2, sp2, ccs, cs, sc, r2z0, z02, dlam2;
     double hz0, thz0, rhshz0, ca, sa, lp, lamc;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0, 0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double t, z1, z2, dl1, dl2, sp, cp;
 
     sp = sin(lp.phi);
@@ -37,7 +39,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double cz1, cz2, s, d, cp, sp;
 
     cz1 = cos (hypot(xy.y, xy.x + Q->hz0));
@@ -59,8 +61,8 @@ static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
 
 PJ *PROJECTION(tpeqd) {
     double lam_1, lam_2, phi_1, phi_2, A12, pp;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_urm5.c b/src/projections/urm5.cpp
index 293de8cf..0e3c7e3c 100644
--- a/src/PJ_urm5.c
+++ b/src/projections/urm5.cpp
@@ -8,14 +8,16 @@
 
 PROJ_HEAD(urm5, "Urmaev V") "\n\tPCyl, Sph, no inv\n\tn= q= alpha=";
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double m, rmn, q3, n;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0, 0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double t;
 
     t = lp.phi = aasin (P->ctx, Q->n * sin (lp.phi));
@@ -28,8 +30,8 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 PJ *PROJECTION(urm5) {
     double alpha, t;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
@@ -47,7 +49,7 @@ PJ *PROJECTION(urm5) {
     Q->rmn = 1. / (Q->m * Q->n);
 
     P->es = 0.;
-    P->inv = 0;
+    P->inv = nullptr;
     P->fwd = s_forward;
 
     return P;
diff --git a/src/PJ_urmfps.c b/src/projections/urmfps.cpp
index 467fc9bc..7103222a 100644
--- a/src/PJ_urmfps.c
+++ b/src/projections/urmfps.cpp
@@ -9,9 +9,11 @@
 PROJ_HEAD(urmfps, "Urmaev Flat-Polar Sinusoidal") "\n\tPCyl, Sph\n\tn=";
 PROJ_HEAD(wag1, "Wagner I (Kavraisky VI)") "\n\tPCyl, Sph";
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double  n, C_y;
 };
+} // anonymous namespace
 
 #define C_x 0.8773826753
 #define Cy 1.139753528477
@@ -19,24 +21,24 @@ struct pj_opaque {
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0, 0.0};
-    lp.phi = aasin (P->ctx,P->opaque->n * sin (lp.phi));
+    lp.phi = aasin (P->ctx,static_cast<struct pj_opaque*>(P->opaque)->n * sin (lp.phi));
     xy.x = C_x * lp.lam * cos (lp.phi);
-    xy.y = P->opaque->C_y * lp.phi;
+    xy.y = static_cast<struct pj_opaque*>(P->opaque)->C_y * lp.phi;
     return xy;
 }
 
 
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0, 0.0};
-    xy.y /= P->opaque->C_y;
-    lp.phi = aasin(P->ctx, sin (xy.y) / P->opaque->n);
+    xy.y /= static_cast<struct pj_opaque*>(P->opaque)->C_y;
+    lp.phi = aasin(P->ctx, sin (xy.y) / static_cast<struct pj_opaque*>(P->opaque)->n);
     lp.lam = xy.x / (C_x * cos (xy.y));
     return lp;
 }
 
 
 static PJ *setup(PJ *P) {
-    P->opaque->C_y = Cy / P->opaque->n;
+    static_cast<struct pj_opaque*>(P->opaque)->C_y = Cy / static_cast<struct pj_opaque*>(P->opaque)->n;
     P->es = 0.;
     P->inv = s_inverse;
     P->fwd = s_forward;
@@ -45,15 +47,15 @@ static PJ *setup(PJ *P) {
 
 
 PJ *PROJECTION(urmfps) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
 
     P->opaque = Q;
 
     if (pj_param(P->ctx, P->params, "tn").i) {
-        P->opaque->n = pj_param(P->ctx, P->params, "dn").f;
-        if (P->opaque->n <= 0. || P->opaque->n > 1.)
+        static_cast<struct pj_opaque*>(P->opaque)->n = pj_param(P->ctx, P->params, "dn").f;
+        if (static_cast<struct pj_opaque*>(P->opaque)->n <= 0. || static_cast<struct pj_opaque*>(P->opaque)->n > 1.)
             return pj_default_destructor(P, PJD_ERR_N_OUT_OF_RANGE);
     } else {
         return pj_default_destructor(P, PJD_ERR_N_OUT_OF_RANGE);
@@ -64,11 +66,11 @@ PJ *PROJECTION(urmfps) {
 
 
 PJ *PROJECTION(wag1) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
-    P->opaque->n = 0.8660254037844386467637231707;
+    static_cast<struct pj_opaque*>(P->opaque)->n = 0.8660254037844386467637231707;
     return setup(P);
 }
diff --git a/src/PJ_vandg.c b/src/projections/vandg.cpp
index d148e210..d148e210 100644
--- a/src/PJ_vandg.c
+++ b/src/projections/vandg.cpp
diff --git a/src/PJ_vandg2.c b/src/projections/vandg2.cpp
index 447cb782..61d50044 100644
--- a/src/PJ_vandg2.c
+++ b/src/projections/vandg2.cpp
@@ -5,9 +5,11 @@
 
 #include "projects.h"
 
+namespace { // anonymous namespace
 struct pj_opaque {
     int vdg3;
 };
+} // anonymous namespace
 
 PROJ_HEAD(vandg2, "van der Grinten II") "\n\tMisc Sph, no inv";
 PROJ_HEAD(vandg3, "van der Grinten III") "\n\tMisc Sph, no inv";
@@ -17,7 +19,7 @@ PROJ_HEAD(vandg3, "van der Grinten III") "\n\tMisc Sph, no inv";
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-    struct pj_opaque *Q = P->opaque;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
     double x1, at, bt, ct;
 
     bt = fabs(M_TWO_D_PI * lp.phi);
@@ -49,8 +51,8 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 
 PJ *PROJECTION(vandg2) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
@@ -61,8 +63,8 @@ PJ *PROJECTION(vandg2) {
 }
 
 PJ *PROJECTION(vandg3) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = Q;
 
diff --git a/src/PJ_vandg4.c b/src/projections/vandg4.cpp
index d9a53c87..d9a53c87 100644
--- a/src/PJ_vandg4.c
+++ b/src/projections/vandg4.cpp
diff --git a/src/PJ_wag2.c b/src/projections/wag2.cpp
index 1bee737a..1bee737a 100644
--- a/src/PJ_wag2.c
+++ b/src/projections/wag2.cpp
diff --git a/src/PJ_wag3.c b/src/projections/wag3.cpp
index ccd19d4d..bb1b4d49 100644
--- a/src/PJ_wag3.c
+++ b/src/projections/wag3.cpp
@@ -9,14 +9,16 @@ PROJ_HEAD(wag3, "Wagner III") "\n\tPCyl, Sph\n\tlat_ts=";
 
 #define TWOTHIRD 0.6666666666666666666667
 
+namespace { // anonymous namespace
 struct pj_opaque {
 	double	C_x;
 };
+} // anonymous namespace
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-	xy.x = P->opaque->C_x * lp.lam * cos(TWOTHIRD * lp.phi);
+	xy.x = static_cast<struct pj_opaque*>(P->opaque)->C_x * lp.lam * cos(TWOTHIRD * lp.phi);
 	xy.y = lp.phi;
 	return xy;
 }
@@ -25,21 +27,21 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
 	lp.phi = xy.y;
-	lp.lam = xy.x / (P->opaque->C_x * cos(TWOTHIRD * lp.phi));
+	lp.lam = xy.x / (static_cast<struct pj_opaque*>(P->opaque)->C_x * cos(TWOTHIRD * lp.phi));
 	return lp;
 }
 
 
 PJ *PROJECTION(wag3) {
 	double ts;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
 
     P->opaque = Q;
 
 	ts = pj_param (P->ctx, P->params, "rlat_ts").f;
-	P->opaque->C_x = cos (ts) / cos (2.*ts/3.);
+	static_cast<struct pj_opaque*>(P->opaque)->C_x = cos (ts) / cos (2.*ts/3.);
 	P->es = 0.;
     P->inv = s_inverse;
     P->fwd = s_forward;
diff --git a/src/PJ_wag7.c b/src/projections/wag7.cpp
index 2009e672..c8807f12 100644
--- a/src/PJ_wag7.c
+++ b/src/projections/wag7.cpp
@@ -24,7 +24,7 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 
 PJ *PROJECTION(wag7) {
     P->fwd = s_forward;
-    P->inv = 0;
+    P->inv = nullptr;
     P->es = 0.;
     return P;
 }
diff --git a/src/PJ_wink1.c b/src/projections/wink1.cpp
index 865cc6ac..de2f55ee 100644
--- a/src/PJ_wink1.c
+++ b/src/projections/wink1.cpp
@@ -7,15 +7,17 @@
 
 PROJ_HEAD(wink1, "Winkel I") "\n\tPCyl, Sph\n\tlat_ts=";
 
+namespace { // anonymous namespace
 struct pj_opaque {
 	double	cosphi1;
 };
+} // anonymous namespace
 
 
 
 static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
     XY xy = {0.0,0.0};
-	xy.x = .5 * lp.lam * (P->opaque->cosphi1 + cos(lp.phi));
+	xy.x = .5 * lp.lam * (static_cast<struct pj_opaque*>(P->opaque)->cosphi1 + cos(lp.phi));
 	xy.y = lp.phi;
 	return (xy);
 }
@@ -24,18 +26,18 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
     LP lp = {0.0,0.0};
 	lp.phi = xy.y;
-	lp.lam = 2. * xy.x / (P->opaque->cosphi1 + cos(lp.phi));
+	lp.lam = 2. * xy.x / (static_cast<struct pj_opaque*>(P->opaque)->cosphi1 + cos(lp.phi));
 	return (lp);
 }
 
 
 PJ *PROJECTION(wink1) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
-	P->opaque->cosphi1 = cos (pj_param(P->ctx, P->params, "rlat_ts").f);
+	static_cast<struct pj_opaque*>(P->opaque)->cosphi1 = cos (pj_param(P->ctx, P->params, "rlat_ts").f);
 	P->es = 0.;
     P->inv = s_inverse;
     P->fwd = s_forward;
diff --git a/src/PJ_wink2.c b/src/projections/wink2.cpp
index f8e9af09..74a47283 100644
--- a/src/PJ_wink2.c
+++ b/src/projections/wink2.cpp
@@ -7,7 +7,11 @@
 
 PROJ_HEAD(wink2, "Winkel II") "\n\tPCyl, Sph, no inv\n\tlat_1=";
 
-struct pj_opaque { double	cosphi1; };
+namespace { // anonymous namespace
+struct pj_opaque {
+    double	cosphi1;
+};
+} // anonymous namespace
 
 #define MAX_ITER    10
 #define LOOP_TOL    1e-7
@@ -31,21 +35,21 @@ static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
 		lp.phi = (lp.phi < 0.) ? -M_HALFPI : M_HALFPI;
 	else
 		lp.phi *= 0.5;
-	xy.x = 0.5 * lp.lam * (cos (lp.phi) + P->opaque->cosphi1);
+	xy.x = 0.5 * lp.lam * (cos (lp.phi) + static_cast<struct pj_opaque*>(P->opaque)->cosphi1);
 	xy.y = M_FORTPI * (sin (lp.phi) + xy.y);
 	return xy;
 }
 
 
 PJ *PROJECTION(wink2) {
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = Q;
 
-	P->opaque->cosphi1 = cos(pj_param(P->ctx, P->params, "rlat_1").f);
+	static_cast<struct pj_opaque*>(P->opaque)->cosphi1 = cos(pj_param(P->ctx, P->params, "rlat_1").f);
 	P->es  = 0.;
-    P->inv = 0;
+    P->inv = nullptr;
     P->fwd = s_forward;
 
     return P;
diff --git a/src/projects.h b/src/projects.h
index 11467d56..b76205a5 100644
--- a/src/projects.h
+++ b/src/projects.h
@@ -197,7 +197,6 @@ struct PJconsts;
 
 union  PJ_COORD;
 struct geod_geodesic;
-struct pj_opaque;
 struct ARG_list;
 struct PJ_REGION_S;
 typedef struct PJ_REGION_S  PJ_Region;
@@ -260,7 +259,7 @@ PJ_OPERATOR:
 
 *****************************************************************************/
 typedef    PJ       *(* PJ_CONSTRUCTOR) (PJ *);
-typedef    void     *(* PJ_DESTRUCTOR)  (PJ *, int);
+typedef    PJ       *(* PJ_DESTRUCTOR)  (PJ *, int);
 typedef    PJ_COORD  (* PJ_OPERATOR)    (PJ_COORD, PJ *);
 /****************************************************************************/
 
@@ -290,7 +289,7 @@ struct PJconsts {
     char *def_ellps;
 
     struct geod_geodesic *geod;    /* For geodesic computations */
-    struct pj_opaque *opaque;      /* Projection specific parameters, Defined in PJ_*.c */
+    void *opaque;      /* Projection specific parameters, Defined in PJ_*.c */
     int inverted;                  /* Tell high level API functions to swap inv/fwd */
 
 
@@ -493,10 +492,10 @@ typedef union { double  f; int  i; char *s; } PROJVALUE;
 
 
 struct PJ_DATUMS {
-    char    *id;           /* datum keyword */
-    char    *defn;         /* ie. "to_wgs84=..." */
-    char    *ellipse_id;   /* ie from ellipse table */
-    char    *comments;     /* EPSG code, etc */
+    const char    *id;           /* datum keyword */
+    const char    *defn;         /* ie. "to_wgs84=..." */
+    const char    *ellipse_id;   /* ie from ellipse table */
+    const char    *comments;     /* EPSG code, etc */
 };
 
 
@@ -628,8 +627,8 @@ C_NAMESPACE PJ *pj_##name (PJ *P) {                          \
     if (P)                                                   \
         return pj_projection_specific_setup_##name (P);      \
     P = (PJ*) pj_calloc (1, sizeof(PJ));                     \
-    if (0==P)                                                \
-        return 0;                                            \
+    if (nullptr==P)                                          \
+        return nullptr;                                      \
     P->destructor = pj_default_destructor;                   \
     P->descr = des_##name;                                   \
     P->need_ellps = NEED_ELLPS;                              \
@@ -828,7 +827,7 @@ extern char const PROJ_DLL pj_release[];
 
 struct PJ_DATUMS           PROJ_DLL *pj_get_datums_ref( void );
 
-void *pj_default_destructor (PJ *P, int errlev);
+PJ *pj_default_destructor (PJ *P, int errlev);
 
 double PROJ_DLL pj_atof( const char* nptr );
 double pj_strtod( const char *nptr, char **endptr );
diff --git a/src/pj_qsfn.c b/src/qsfn.cpp
index c18a7b95..c18a7b95 100644
--- a/src/pj_qsfn.c
+++ b/src/qsfn.cpp
diff --git a/src/pj_release.c b/src/release.cpp
index 9beb45ef..9beb45ef 100644
--- a/src/pj_release.c
+++ b/src/release.cpp
diff --git a/src/rtodms.c b/src/rtodms.cpp
index 674cebdf..674cebdf 100644
--- a/src/rtodms.c
+++ b/src/rtodms.cpp
diff --git a/src/pj_strerrno.c b/src/strerrno.cpp
index 16042f79..18ed0d33 100644
--- a/src/pj_strerrno.c
+++ b/src/strerrno.cpp
@@ -79,7 +79,7 @@ char *pj_strerrno(int err) {
     size_t adjusted_err;
 
     if (0==err)
-        return 0;
+        return nullptr;
 
     /* System error codes are positive */
     if (err > 0) {
diff --git a/src/pj_strtod.c b/src/strtod.cpp
index f604a013..5a360c2e 100644
--- a/src/pj_strtod.c
+++ b/src/strtod.cpp
@@ -65,7 +65,7 @@
  */
 double pj_atof( const char* nptr )
 {
-    return pj_strtod(nptr, NULL);
+    return pj_strtod(nptr, nullptr);
 }
 
 
@@ -134,7 +134,7 @@ static char* replace_point_by_locale_point(const char* pszNumber, char point,
                 else {
                     pszNew = pj_strdup(pszNumber);
                     if (!pszNew)
-                        return NULL;
+                        return nullptr;
                 }
                 if( pszLocalePoint )
                     pszNew[pszLocalePoint - pszNumber] = ' ';
diff --git a/src/geodtest.c b/src/tests/geodtest.cpp
index 0ee86d5c..6b3ea8b2 100644
--- a/src/geodtest.c
+++ b/src/tests/geodtest.cpp
@@ -157,7 +157,7 @@ static int testdirect() {
     s12 = testcases[i][6]; a12 = testcases[i][7]; m12 = testcases[i][8];
     M12 = testcases[i][9]; M21 = testcases[i][10]; S12 = testcases[i][11];
     a12a = geod_gendirect(&g, lat1, lon1, azi1, flags, s12,
-              &lat2a, &lon2a, &azi2a, 0,
+              &lat2a, &lon2a, &azi2a, nullptr,
               &m12a, &M12a, &M21a, &S12a);
     result += checkEquals(lat2, lat2a, 1e-13);
     result += checkEquals(lon2, lon2a, 1e-13);
@@ -246,7 +246,7 @@ static int GeodSolve4() {
   int result = 0;
   geod_init(&g, wgs84_a, wgs84_f);
   geod_inverse(&g, 36.493349428792, 0, 36.49334942879201, .0000008,
-               &s12, 0, 0);
+               &s12, nullptr, nullptr);
   result += checkEquals(s12, 0.072, 0.5e-3);
   return result;
 }
@@ -277,13 +277,13 @@ static int GeodSolve6() {
   int result = 0;
   geod_init(&g, wgs84_a, wgs84_f);
   geod_inverse(&g, 88.202499451857, 0,
-               -88.202499451857, 179.981022032992859592, &s12, 0, 0);
+               -88.202499451857, 179.981022032992859592, &s12, nullptr, nullptr);
   result += checkEquals(s12, 20003898.214, 0.5e-3);
   geod_inverse(&g, 89.262080389218, 0,
-               -89.262080389218, 179.992207982775375662, &s12, 0, 0);
+               -89.262080389218, 179.992207982775375662, &s12, nullptr, nullptr);
   result += checkEquals(s12, 20003925.854, 0.5e-3);
   geod_inverse(&g, 89.333123580033, 0,
-               -89.333123580032997687, 179.99295812360148422, &s12, 0, 0);
+               -89.333123580032997687, 179.99295812360148422, &s12, nullptr, nullptr);
   result += checkEquals(s12, 20003926.881, 0.5e-3);
   return result;
 }
@@ -295,7 +295,7 @@ static int GeodSolve9() {
   int result = 0;
   geod_init(&g, wgs84_a, wgs84_f);
   geod_inverse(&g, 56.320923501171, 0,
-               -56.320923501171, 179.664747671772880215, &s12, 0, 0);
+               -56.320923501171, 179.664747671772880215, &s12, nullptr, nullptr);
   result += checkEquals(s12, 19993558.287, 0.5e-3);
   return result;
 }
@@ -308,7 +308,7 @@ static int GeodSolve10() {
   int result = 0;
   geod_init(&g, wgs84_a, wgs84_f);
   geod_inverse(&g, 52.784459512564, 0,
-               -52.784459512563990912, 179.634407464943777557, &s12, 0, 0);
+               -52.784459512563990912, 179.634407464943777557, &s12, nullptr, nullptr);
   result += checkEquals(s12, 19991596.095, 0.5e-3);
   return result;
 }
@@ -321,7 +321,7 @@ static int GeodSolve11() {
   int result = 0;
   geod_init(&g, wgs84_a, wgs84_f);
   geod_inverse(&g, 48.522876735459, 0,
-               -48.52287673545898293, 179.599720456223079643, &s12, 0, 0);
+               -48.52287673545898293, 179.599720456223079643, &s12, nullptr, nullptr);
   result += checkEquals(s12, 19989144.774, 0.5e-3);
   return result;
 }
@@ -367,7 +367,7 @@ static int GeodSolve15() {
   int result = 0;
   geod_init(&g, 6.4e6, -1/150.0);
   geod_gendirect(&g, 1, 2, 3, 0, 4,
-                 0, 0, 0, 0, 0, 0, 0, &S12);
+                 nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, &S12);
   result += checkEquals(S12, 23700, 0.5);
   return result;
 }
@@ -381,12 +381,12 @@ static int GeodSolve17() {
   unsigned flags = GEOD_LONG_UNROLL;
   geod_init(&g, wgs84_a, wgs84_f);
   geod_gendirect(&g, 40, -75, -10, flags, 2e7,
-                 &lat2, &lon2, &azi2, 0, 0, 0, 0, 0);
+                 &lat2, &lon2, &azi2, nullptr, nullptr, nullptr, nullptr, nullptr);
   result += checkEquals(lat2, -39, 1);
   result += checkEquals(lon2, -254, 1);
   result += checkEquals(azi2, -170, 1);
   geod_lineinit(&l, &g, 40, -75, -10, 0);
-  geod_genposition(&l, flags, 2e7, &lat2, &lon2, &azi2, 0, 0, 0, 0, 0);
+  geod_genposition(&l, flags, 2e7, &lat2, &lon2, &azi2, nullptr, nullptr, nullptr, nullptr, nullptr);
   result += checkEquals(lat2, -39, 1);
   result += checkEquals(lon2, -254, 1);
   result += checkEquals(azi2, -170, 1);
@@ -407,7 +407,7 @@ static int GeodSolve26() {
   struct geod_geodesic g;
   int result = 0;
   geod_init(&g, 6.4e6, 0);
-  geod_geninverse(&g, 1, 2, 3, 4, 0, 0, 0, 0, 0, 0, &S12);
+  geod_geninverse(&g, 1, 2, 3, 4, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, &S12);
   result += checkEquals(S12, 49911046115.0, 0.5);
   return result;
 }
@@ -419,7 +419,7 @@ static int GeodSolve28() {
   struct geod_geodesic g;
   int result = 0;
   geod_init(&g, 6.4e6, 0.1);
-  a12 = geod_gendirect(&g, 1, 2, 10, 0, 5e6, 0, 0, 0, 0, 0, 0, 0, 0);
+  a12 = geod_gendirect(&g, 1, 2, 10, 0, 5e6, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr);
   result += checkEquals(a12, 48.55570690, 0.5e-8);
   return result;
 }
@@ -527,12 +527,12 @@ static int GeodSolve61() {
   unsigned flags = GEOD_LONG_UNROLL;
   geod_init(&g, wgs84_a, wgs84_f);
   geod_gendirect(&g, 45, 0, -0.000000000000000003, flags, 1e7,
-                 &lat2, &lon2, &azi2, 0, 0, 0, 0, 0);
+                 &lat2, &lon2, &azi2, nullptr, nullptr, nullptr, nullptr, nullptr);
   result += checkEquals(lat2, 45.30632, 0.5e-5);
   result += checkEquals(lon2, -180, 0.5e-5);
   result += checkEquals(fabs(azi2), 180, 0.5e-5);
   geod_inverseline(&l, &g, 45, 0, 80, -0.000000000000000003, 0);
-  geod_genposition(&l, flags, 1e7, &lat2, &lon2, &azi2, 0, 0, 0, 0, 0);
+  geod_genposition(&l, flags, 1e7, &lat2, &lon2, &azi2, nullptr, nullptr, nullptr, nullptr, nullptr);
   result += checkEquals(lat2, 45.30632, 0.5e-5);
   result += checkEquals(lon2, -180, 0.5e-5);
   result += checkEquals(fabs(azi2), 180, 0.5e-5);
@@ -585,11 +585,11 @@ static int GeodSolve67() {
   unsigned flags = GEOD_LONG_UNROLL;
   geod_init(&g, wgs84_a, wgs84_f);
   geod_inverseline(&l, &g, -5, -0.000000000000002, -10, 180, 0);
-  geod_genposition(&l, flags, 2e7, &lat2, &lon2, &azi2, 0, 0, 0, 0, 0);
+  geod_genposition(&l, flags, 2e7, &lat2, &lon2, &azi2, nullptr, nullptr, nullptr, nullptr, nullptr);
   result += checkEquals(lat2, 4.96445, 0.5e-5);
   result += checkEquals(lon2, -180.00000, 0.5e-5);
   result += checkEquals(azi2, -0.00000, 0.5e-5);
-  geod_genposition(&l, flags, 0.5 * l.s13, &lat2, &lon2, &azi2, 0, 0, 0, 0, 0);
+  geod_genposition(&l, flags, 0.5 * l.s13, &lat2, &lon2, &azi2, nullptr, nullptr, nullptr, nullptr, nullptr);
   result += checkEquals(lat2, -87.52461, 0.5e-5);
   result += checkEquals(lon2, -0.00000, 0.5e-5);
   result += checkEquals(azi2, -180.00000, 0.5e-5);
@@ -647,7 +647,7 @@ static void polylength(const struct geod_geodesic* g,
   geod_polygon_init(&p, 1);
   for (i = 0; i < N; ++i)
     geod_polygon_addpoint(g, &p, points[i][0], points[i][1]);
-  geod_polygon_compute(g, &p, 0, 1, 0, perimeter);
+  geod_polygon_compute(g, &p, 0, 1, nullptr, perimeter);
 }
 
 static int GeodSolve74() {
@@ -707,10 +707,10 @@ static int GeodSolve80() {
   struct geod_geodesicline l;
   int result = 0;
   geod_init(&g, wgs84_a, wgs84_f);
-  geod_geninverse(&g, 0, 0, 0, 90, 0, 0, 0, 0, &M12, &M21, 0);
+  geod_geninverse(&g, 0, 0, 0, 90, nullptr, nullptr, nullptr, nullptr, &M12, &M21, nullptr);
   result += checkEquals(M12, -0.00528427534, 0.5e-10);
   result += checkEquals(M21, -0.00528427534, 0.5e-10);
-  geod_geninverse(&g, 0, 0, 1e-6, 1e-6, 0, 0, 0, 0, &M12, &M21, 0);
+  geod_geninverse(&g, 0, 0, 1e-6, 1e-6, nullptr, nullptr, nullptr, nullptr, &M12, &M21, nullptr);
   result += checkEquals(M12, 1, 0.5e-10);
   result += checkEquals(M21, 1, 0.5e-10);
   a12 = geod_geninverse(&g, 20.001, 0, 20.001, 0,
@@ -735,7 +735,7 @@ static int GeodSolve80() {
   result += checkEquals(S12, 127516405431022, 0.5);
   /* An incapable line which can't take distance as input */
   geod_lineinit(&l, &g, 1, 2, 90, GEOD_LATITUDE);
-  a12 = geod_genposition(&l, 0, 1000, 0, 0, 0, 0, 0, 0, 0, 0);
+  a12 = geod_genposition(&l, 0, 1000, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr);
   result += checkNaN(a12);
   return result;
 }
@@ -853,33 +853,33 @@ static int Planimeter15() {
   geod_polygon_init(&p, 0);
   geod_polygon_addpoint(&g, &p, lat[0], lon[0]);
   geod_polygon_addpoint(&g, &p, lat[1], lon[1]);
-  geod_polygon_testpoint(&g, &p, lat[2], lon[2], 0, 1, &area, 0);
+  geod_polygon_testpoint(&g, &p, lat[2], lon[2], 0, 1, &area, nullptr);
   result += checkEquals(area, r, 0.5);
-  geod_polygon_testpoint(&g, &p, lat[2], lon[2], 0, 0, &area, 0);
+  geod_polygon_testpoint(&g, &p, lat[2], lon[2], 0, 0, &area, nullptr);
   result += checkEquals(area, r, 0.5);
-  geod_polygon_testpoint(&g, &p, lat[2], lon[2], 1, 1, &area, 0);
+  geod_polygon_testpoint(&g, &p, lat[2], lon[2], 1, 1, &area, nullptr);
   result += checkEquals(area, -r, 0.5);
-  geod_polygon_testpoint(&g, &p, lat[2], lon[2], 1, 0, &area, 0);
+  geod_polygon_testpoint(&g, &p, lat[2], lon[2], 1, 0, &area, nullptr);
   result += checkEquals(area, a0-r, 0.5);
-  geod_inverse(&g, lat[1], lon[1], lat[2], lon[2], &s12, &azi1, 0);
-  geod_polygon_testedge(&g, &p, azi1, s12, 0, 1, &area, 0);
+  geod_inverse(&g, lat[1], lon[1], lat[2], lon[2], &s12, &azi1, nullptr);
+  geod_polygon_testedge(&g, &p, azi1, s12, 0, 1, &area, nullptr);
   result += checkEquals(area, r, 0.5);
-  geod_polygon_testedge(&g, &p, azi1, s12, 0, 0, &area, 0);
+  geod_polygon_testedge(&g, &p, azi1, s12, 0, 0, &area, nullptr);
   result += checkEquals(area, r, 0.5);
-  geod_polygon_testedge(&g, &p, azi1, s12, 1, 1, &area, 0);
+  geod_polygon_testedge(&g, &p, azi1, s12, 1, 1, &area, nullptr);
   result += checkEquals(area, -r, 0.5);
-  geod_polygon_testedge(&g, &p, azi1, s12, 1, 0, &area, 0);
+  geod_polygon_testedge(&g, &p, azi1, s12, 1, 0, &area, nullptr);
   result += checkEquals(area, a0-r, 0.5);
   geod_polygon_addpoint(&g, &p, lat[2], lon[2]);
-  geod_polygon_compute(&g, &p, 0, 1, &area, 0);
+  geod_polygon_compute(&g, &p, 0, 1, &area, nullptr);
   result += checkEquals(area, r, 0.5);
-  geod_polygon_compute(&g, &p, 0, 0, &area, 0);
+  geod_polygon_compute(&g, &p, 0, 0, &area, nullptr);
   result += checkEquals(area, r, 0.5);
-  geod_polygon_compute(&g, &p, 1, 1, &area, 0);
+  geod_polygon_compute(&g, &p, 1, 1, &area, nullptr);
   result += checkEquals(area, -r, 0.5);
-  geod_polygon_compute(&g, &p, 1, 0, &area, 0);
+  geod_polygon_compute(&g, &p, 1, 0, &area, nullptr);
   result += checkEquals(area, a0-r, 0.5);
-  geod_polygonarea(&g, lat, lon, 3, &area, 0);
+  geod_polygonarea(&g, lat, lon, 3, &area, nullptr);
   result += checkEquals(area, r, 0.5);
   return result;
 }
@@ -907,14 +907,14 @@ static int Planimeter19() {
   result += area == 0 ? 0 : 1;
   result += perim == 0 ? 0 : 1;
   geod_polygon_init(&p, 1);
-  geod_polygon_compute(&g, &p, 0, 1, 0, &perim);
+  geod_polygon_compute(&g, &p, 0, 1, nullptr, &perim);
   result += perim == 0 ? 0 : 1;
-  geod_polygon_testpoint(&g, &p, 1, 1, 0, 1, 0, &perim);
+  geod_polygon_testpoint(&g, &p, 1, 1, 0, 1, nullptr, &perim);
   result += perim == 0 ? 0 : 1;
-  geod_polygon_testedge(&g, &p, 90, 1000, 0, 1, 0, &perim);
+  geod_polygon_testedge(&g, &p, 90, 1000, 0, 1, nullptr, &perim);
   result += checkNaN(perim);
   geod_polygon_addpoint(&g, &p, 1, 1);
-  geod_polygon_compute(&g, &p, 0, 1, 0, &perim);
+  geod_polygon_compute(&g, &p, 0, 1, nullptr, &perim);
   result += perim == 0 ? 0 : 1;
   return result;
 }
@@ -944,30 +944,30 @@ static int Planimeter21() {
   for (i = 3; i <= 4; ++i) {
     geod_polygon_addpoint(&g, &p, lat,  60);
     geod_polygon_addpoint(&g, &p, lat, 180);
-    geod_polygon_testpoint(&g, &p, lat, -60, 0, 1, &area, 0);
+    geod_polygon_testpoint(&g, &p, lat, -60, 0, 1, &area, nullptr);
     if (i != 4) result += checkEquals(area,  i*r, 0.5);
-    geod_polygon_testpoint(&g, &p, lat, -60, 0, 0, &area, 0);
+    geod_polygon_testpoint(&g, &p, lat, -60, 0, 0, &area, nullptr);
     if (i != 4) result += checkEquals(area,  i*r, 0.5);
-    geod_polygon_testpoint(&g, &p, lat, -60, 1, 1, &area, 0);
+    geod_polygon_testpoint(&g, &p, lat, -60, 1, 1, &area, nullptr);
     if (i != 4) result += checkEquals(area, -i*r, 0.5);
-    geod_polygon_testpoint(&g, &p, lat, -60, 1, 0, &area, 0);
+    geod_polygon_testpoint(&g, &p, lat, -60, 1, 0, &area, nullptr);
     result += checkEquals(area, -i*r + a0, 0.5);
-    geod_polygon_testedge(&g, &p, a, s, 0, 1, &area, 0);
+    geod_polygon_testedge(&g, &p, a, s, 0, 1, &area, nullptr);
     if (i != 4) result += checkEquals(area,  i*r, 0.5);
-    geod_polygon_testedge(&g, &p, a, s, 0, 0, &area, 0);
+    geod_polygon_testedge(&g, &p, a, s, 0, 0, &area, nullptr);
     if (i != 4) result += checkEquals(area,  i*r, 0.5);
-    geod_polygon_testedge(&g, &p, a, s, 1, 1, &area, 0);
+    geod_polygon_testedge(&g, &p, a, s, 1, 1, &area, nullptr);
     if (i != 4) result += checkEquals(area, -i*r, 0.5);
-    geod_polygon_testedge(&g, &p, a, s, 1, 0, &area, 0);
+    geod_polygon_testedge(&g, &p, a, s, 1, 0, &area, nullptr);
     result += checkEquals(area, -i*r + a0, 0.5);
     geod_polygon_addpoint(&g, &p, lat, -60);
-    geod_polygon_compute(&g, &p, 0, 1, &area, 0);
+    geod_polygon_compute(&g, &p, 0, 1, &area, nullptr);
     if (i != 4) result += checkEquals(area,  i*r, 0.5);
-    geod_polygon_compute(&g, &p, 0, 0, &area, 0);
+    geod_polygon_compute(&g, &p, 0, 0, &area, nullptr);
     if (i != 4) result += checkEquals(area,  i*r, 0.5);
-    geod_polygon_compute(&g, &p, 1, 1, &area, 0);
+    geod_polygon_compute(&g, &p, 1, 1, &area, nullptr);
     if (i != 4) result += checkEquals(area, -i*r, 0.5);
-    geod_polygon_compute(&g, &p, 1, 0, &area, 0);
+    geod_polygon_compute(&g, &p, 1, 0, &area, nullptr);
     result += checkEquals(area, -i*r + a0, 0.5);
   }
   return result;
@@ -985,7 +985,7 @@ static int AddEdge1() {
   geod_polygon_addedge(&g, &p,  90, 1000);
   geod_polygon_addedge(&g, &p,   0, 1000);
   geod_polygon_addedge(&g, &p, -90, 1000);
-  geod_polygon_compute(&g, &p, 0, 1, &area, 0);
+  geod_polygon_compute(&g, &p, 0, 1, &area, nullptr);
   result += checkEquals(area, 1000000.0, 0.01);
   return result;
 }
@@ -1007,16 +1007,16 @@ static int EmptyPoly() {
   result += area == 0 ? 0 : 1;
   result += perim == 0 ? 0 : 1;
   geod_polygon_init(&p, 1);
-  geod_polygon_testpoint(&g, &p, 1, 1, 0, 1, 0, &perim);
+  geod_polygon_testpoint(&g, &p, 1, 1, 0, 1, nullptr, &perim);
   result += perim == 0 ? 0 : 1;
-  geod_polygon_testedge(&g, &p, 90, 1000, 0, 1, 0, &perim);
+  geod_polygon_testedge(&g, &p, 90, 1000, 0, 1, nullptr, &perim);
   result += checkNaN(perim);
-  geod_polygon_compute(&g, &p, 0, 1, 0, &perim);
+  geod_polygon_compute(&g, &p, 0, 1, nullptr, &perim);
   result += perim == 0 ? 0 : 1;
   geod_polygon_addpoint(&g, &p, 1, 1);
-  geod_polygon_testedge(&g, &p, 90, 1000, 0, 1, 0, &perim);
+  geod_polygon_testedge(&g, &p, 90, 1000, 0, 1, nullptr, &perim);
   result += checkEquals(perim, 1000, 1e-10);
-  geod_polygon_testpoint(&g, &p, 2, 2, 0, 1, 0, &perim);
+  geod_polygon_testpoint(&g, &p, 2, 2, 0, 1, nullptr, &perim);
   result += checkEquals(perim, 156876.149, 0.5e-3);
   return result;
 }
diff --git a/src/multistresstest.c b/src/tests/multistresstest.cpp
index b0bd5c9c..234783b3 100644
--- a/src/multistresstest.c
+++ b/src/tests/multistresstest.cpp
@@ -177,7 +177,7 @@ static TestItem test_list[] = {
 
 static volatile int active_thread_count = 0;
 
-static projPJ* custom_pj_init_plus_ctx(projCtx ctx, const char* def)
+static projPJ custom_pj_init_plus_ctx(projCtx ctx, const char* def)
 {
     if( add_no_defs )
     {
@@ -243,7 +243,7 @@ static void TestThread()
                 dst_pj_list[i] = custom_pj_init_plus_ctx( ctx, test->dst_def );
 
                 {
-                    int skipTest = (src_pj_list[i] == NULL || dst_pj_list[i] == NULL);
+                    int skipTest = (src_pj_list[i] == nullptr || dst_pj_list[i] == nullptr);
 
                     if ( skipTest != test->skip )
                         fprintf( stderr, "Threaded projection initialization does not match unthreaded initialization\n" );
@@ -335,7 +335,7 @@ static void *PosixTestThread( void *pData )
 {
     (void)pData;
     TestThread();
-    return NULL;
+    return nullptr;
 }
 #endif
 
@@ -363,7 +363,7 @@ static int do_main(void)
         src_pj = custom_pj_init_plus_ctx( pj_get_default_ctx(), test->src_def );
         dst_pj = custom_pj_init_plus_ctx( pj_get_default_ctx(), test->dst_def );
 
-        if( src_pj == NULL )
+        if( src_pj == nullptr )
         {
             printf( "Unable to translate:\n%s\n", test->src_def );
             test->skip = 1;
@@ -371,7 +371,7 @@ static int do_main(void)
             continue;
         }
 
-        if( dst_pj == NULL )
+        if( dst_pj == nullptr )
         {
             printf( "Unable to translate:\n%s\n", test->dst_def );
             test->skip = 1;
@@ -439,7 +439,7 @@ static int do_main(void)
         active_thread_count++;
 
         pthread_create( &(ahThread[i]), &hThreadAttr,
-            PosixTestThread, NULL );
+            PosixTestThread, nullptr );
     }
 
     printf( "%d test threads launched.\n", num_threads );
diff --git a/src/test228.c b/src/tests/test228.cpp
index 83d29f8f..fcacd7c9 100644
--- a/src/test228.c
+++ b/src/tests/test228.cpp
@@ -49,7 +49,7 @@ static void* thread_main(void* unused)
         x = -5.2*DEG_TO_RAD;
         y = 50*DEG_TO_RAD;
         proj_ret = pj_transform(p_WGS84_proj,
-                                p_OSGB36_proj, 1, 1, &x, &y, NULL );
+                                p_OSGB36_proj, 1, 1, &x, &y, nullptr );
         x *= RAD_TO_DEG;
         y *= RAD_TO_DEG;
         /*printf("%.18f %.18f\n", x, y); */
@@ -60,7 +60,7 @@ static void* thread_main(void* unused)
 
     pj_free (p_OSGB36_proj);
     pj_free (p_WGS84_proj);
-    return NULL;
+    return nullptr;
 }
 
 int main()
@@ -73,8 +73,8 @@ int main()
     pthread_attr_init(&attr1);
     pthread_attr_init(&attr2);
 
-    pthread_create(&tid1, &attr1, thread_main, NULL);
-    pthread_create(&tid2, &attr2, thread_main, NULL);
+    pthread_create(&tid1, &attr1, thread_main, nullptr);
+    pthread_create(&tid2, &attr2, thread_main, nullptr);
     while(started != 2);
     run = 1;
     for(i=0;i<2;i++)
diff --git a/src/pj_transform.c b/src/transform.cpp
index 6982676e..433fc017 100644
--- a/src/pj_transform.c
+++ b/src/transform.cpp
@@ -31,23 +31,10 @@
 #include <math.h>
 #include <string.h>
 
+#include "proj.h"
 #include "projects.h"
 #include "geocent.h"
 
-
-/* Apply transformation to observation - in forward or inverse direction */
-/* Copied from proj.h */
-enum PJ_DIRECTION {
-    PJ_FWD   =  1,   /* Forward    */
-    PJ_IDENT =  0,   /* Do nothing */
-    PJ_INV   = -1    /* Inverse    */
-};
-typedef enum PJ_DIRECTION PJ_DIRECTION;
-
-/* Copied from proj.h FIXME */
-int  proj_errno_reset (const PJ *P);
-
-
 static int adjust_axis( projCtx ctx, const char *axis, int denormalize_flag,
                            long point_count, int point_offset,
                            double *x, double *y, double *z );
@@ -140,7 +127,7 @@ static int geographic_to_cartesian (PJ *P, PJ_DIRECTION dir, long n, int dist, d
     if (!P->is_geocent)
         return 0;
 
-    if ( z == NULL ) {
+    if ( z == nullptr ) {
         pj_ctx_set_errno( pj_get_ctx(P), PJD_ERR_GEOCENTRIC);
         return PJD_ERR_GEOCENTRIC;
     }
@@ -195,10 +182,10 @@ static int geographic_to_projected (PJ *P, long n, int dist, double *x, double *
     if (P->is_geocent)
         return 0;
 
-    if(P->fwd3d != NULL && !(z == NULL && P->is_latlong))
+    if(P->fwd3d != nullptr && !(z == nullptr && P->is_latlong))
     {
         /* Three dimensions must be defined */
-        if ( z == NULL)
+        if ( z == nullptr)
         {
             pj_ctx_set_errno( pj_get_ctx(P), PJD_ERR_GEOCENTRIC);
             return PJD_ERR_GEOCENTRIC;
@@ -209,11 +196,11 @@ static int geographic_to_projected (PJ *P, long n, int dist, double *x, double *
             XYZ projected_loc;
             LPZ geodetic_loc;
 
-            geodetic_loc.u = x[dist*i];
-            geodetic_loc.v = y[dist*i];
-            geodetic_loc.w = z[dist*i];
+            geodetic_loc.lam = x[dist*i];
+            geodetic_loc.phi = y[dist*i];
+            geodetic_loc.z = z[dist*i];
 
-            if (geodetic_loc.u == HUGE_VAL)
+            if (geodetic_loc.lam == HUGE_VAL)
                 continue;
 
             proj_errno_reset( P );
@@ -230,15 +217,15 @@ static int geographic_to_projected (PJ *P, long n, int dist, double *x, double *
                 }
                 else
                 {
-                    projected_loc.u = HUGE_VAL;
-                    projected_loc.v = HUGE_VAL;
-                    projected_loc.w = HUGE_VAL;
+                    projected_loc.x = HUGE_VAL;
+                    projected_loc.y = HUGE_VAL;
+                    projected_loc.z = HUGE_VAL;
                 }
             }
 
-            x[dist*i] = projected_loc.u;
-            y[dist*i] = projected_loc.v;
-            z[dist*i] = projected_loc.w;
+            x[dist*i] = projected_loc.x;
+            y[dist*i] = projected_loc.y;
+            z[dist*i] = projected_loc.z;
         }
         return 0;
     }
@@ -248,10 +235,10 @@ static int geographic_to_projected (PJ *P, long n, int dist, double *x, double *
         XY         projected_loc;
         LP	       geodetic_loc;
 
-        geodetic_loc.u = x[dist*i];
-        geodetic_loc.v = y[dist*i];
+        geodetic_loc.lam = x[dist*i];
+        geodetic_loc.phi = y[dist*i];
 
-        if( geodetic_loc.u == HUGE_VAL )
+        if( geodetic_loc.lam == HUGE_VAL )
             continue;
 
         proj_errno_reset( P );
@@ -268,13 +255,13 @@ static int geographic_to_projected (PJ *P, long n, int dist, double *x, double *
             }
             else
             {
-                projected_loc.u = HUGE_VAL;
-                projected_loc.v = HUGE_VAL;
+                projected_loc.x = HUGE_VAL;
+                projected_loc.y = HUGE_VAL;
             }
         }
 
-        x[dist*i] = projected_loc.u;
-        y[dist*i] = projected_loc.v;
+        x[dist*i] = projected_loc.x;
+        y[dist*i] = projected_loc.y;
     }
     return 0;
 }
@@ -296,7 +283,7 @@ static int projected_to_geographic (PJ *P, long n, int dist, double *x, double *
         return 0;
 
     /* Check first if projection is invertible. */
-    if( (P->inv3d == NULL) && (P->inv == NULL))
+    if( (P->inv3d == nullptr) && (P->inv == nullptr))
     {
         pj_ctx_set_errno(pj_get_ctx(P), PJD_ERR_NON_CONV_INV_MERI_DIST);
         pj_log( pj_get_ctx(P), PJ_LOG_ERROR,
@@ -305,10 +292,10 @@ static int projected_to_geographic (PJ *P, long n, int dist, double *x, double *
     }
 
     /* If invertible - First try inv3d if defined */
-    if (P->inv3d != NULL && !(z == NULL && P->is_latlong))
+    if (P->inv3d != nullptr && !(z == nullptr && P->is_latlong))
     {
         /* Three dimensions must be defined */
-        if ( z == NULL)
+        if ( z == nullptr)
         {
             pj_ctx_set_errno( pj_get_ctx(P), PJD_ERR_GEOCENTRIC);
             return PJD_ERR_GEOCENTRIC;
@@ -317,13 +304,13 @@ static int projected_to_geographic (PJ *P, long n, int dist, double *x, double *
         for (i=0; i < n; i++)
         {
             XYZ projected_loc;
-            XYZ geodetic_loc;
+            LPZ geodetic_loc;
 
-            projected_loc.u = x[dist*i];
-            projected_loc.v = y[dist*i];
-            projected_loc.w = z[dist*i];
+            projected_loc.x = x[dist*i];
+            projected_loc.y = y[dist*i];
+            projected_loc.z = z[dist*i];
 
-            if (projected_loc.u == HUGE_VAL)
+            if (projected_loc.x == HUGE_VAL)
                 continue;
 
             proj_errno_reset( P );
@@ -340,15 +327,15 @@ static int projected_to_geographic (PJ *P, long n, int dist, double *x, double *
                 }
                 else
                 {
-                    geodetic_loc.u = HUGE_VAL;
-                    geodetic_loc.v = HUGE_VAL;
-                    geodetic_loc.w = HUGE_VAL;
+                    geodetic_loc.lam = HUGE_VAL;
+                    geodetic_loc.phi = HUGE_VAL;
+                    geodetic_loc.z = HUGE_VAL;
                 }
             }
 
-            x[dist*i] = geodetic_loc.u;
-            y[dist*i] = geodetic_loc.v;
-            z[dist*i] = geodetic_loc.w;
+            x[dist*i] = geodetic_loc.lam;
+            y[dist*i] = geodetic_loc.phi;
+            z[dist*i] = geodetic_loc.z;
 
         }
         return 0;
@@ -359,10 +346,10 @@ static int projected_to_geographic (PJ *P, long n, int dist, double *x, double *
         XY         projected_loc;
         LP	       geodetic_loc;
 
-        projected_loc.u = x[dist*i];
-        projected_loc.v = y[dist*i];
+        projected_loc.x = x[dist*i];
+        projected_loc.y = y[dist*i];
 
-        if( projected_loc.u == HUGE_VAL )
+        if( projected_loc.x == HUGE_VAL )
             continue;
 
         proj_errno_reset( P );
@@ -379,13 +366,13 @@ static int projected_to_geographic (PJ *P, long n, int dist, double *x, double *
             }
             else
             {
-                geodetic_loc.u = HUGE_VAL;
-                geodetic_loc.v = HUGE_VAL;
+                geodetic_loc.lam = HUGE_VAL;
+                geodetic_loc.phi = HUGE_VAL;
             }
         }
 
-        x[dist*i] = geodetic_loc.u;
-        y[dist*i] = geodetic_loc.v;
+        x[dist*i] = geodetic_loc.lam;
+        y[dist*i] = geodetic_loc.phi;
     }
     return 0;
 }
@@ -430,7 +417,7 @@ static int height_unit (PJ *P, PJ_DIRECTION dir, long n, int dist, double *z) {
     /* Nothing to do? */
     if (fac==1.0)
         return 0;
-    if (0==z)
+    if (nullptr==z)
         return 0;
     if (P->is_latlong)
         return 0; /* done in pj_inv3d() / pj_fwd3d() */
@@ -451,7 +438,7 @@ static int geometric_to_orthometric (PJ *P, PJ_DIRECTION dir, long n, int dist,
     int err;
     if (0==P->has_geoid_vgrids)
         return 0;
-    if (z==0)
+    if (z==nullptr)
         return PJD_ERR_GEOCENTRIC;
     err = pj_apply_vgridshift (P, "sgeoidgrids",
               &(P->vgridlist_geoid),
@@ -713,7 +700,7 @@ int pj_compare_datums( PJ *srcdefn, PJ *dstdefn )
             pj_param(srcdefn->ctx, srcdefn->params,"snadgrids").s;
         const char* dstnadgrids =
             pj_param(dstdefn->ctx, dstdefn->params,"snadgrids").s;
-        return srcnadgrids != 0 && dstnadgrids != 0 &&
+        return srcnadgrids != nullptr && dstnadgrids != nullptr &&
                strcmp( srcnadgrids, dstnadgrids ) == 0;
     }
     else
@@ -859,7 +846,7 @@ int pj_datum_transform( PJ *src, PJ *dst,
 /* -------------------------------------------------------------------- */
 /*      Create a temporary Z array if one is not provided.              */
 /* -------------------------------------------------------------------- */
-    if( z == NULL )
+    if( z == nullptr )
     {
         size_t	bytes = sizeof(double) * point_count * point_offset;
         z = (double *) pj_malloc(bytes);
@@ -1024,7 +1011,7 @@ static int adjust_axis( projCtx ctx,
             {
                 double *target;
 
-                if( i_axis == 2 && z == NULL )
+                if( i_axis == 2 && z == nullptr )
                     continue;
 
                 if( i_axis == 0 )
diff --git a/src/PJ_affine.c b/src/transformations/affine.cpp
index 0d8b6374..e2b668d3 100644
--- a/src/PJ_affine.c
+++ b/src/transformations/affine.cpp
@@ -32,6 +32,7 @@
 PROJ_HEAD(affine, "Affine transformation");
 PROJ_HEAD(geogoffset, "Geographic Offset");
 
+namespace { // anonymous namespace
 struct pj_affine_coeffs {
     double s11;
     double s12;
@@ -44,7 +45,9 @@ struct pj_affine_coeffs {
     double s33;
     double tscale;
 };
+} // anonymous namespace
 
+namespace { // anonymous namespace
 struct pj_opaque_affine {
     double xoff;
     double yoff;
@@ -53,6 +56,7 @@ struct pj_opaque_affine {
     struct pj_affine_coeffs forward;
     struct pj_affine_coeffs reverse;
 };
+} // anonymous namespace
 
 
 static PJ_COORD forward_4d(PJ_COORD obs, PJ *P) {
@@ -107,9 +111,9 @@ static LP reverse_2d(XY xy, PJ *P) {
 }
 
 static struct pj_opaque_affine * initQ() {
-    struct pj_opaque_affine *Q = pj_calloc(1, sizeof(struct pj_opaque_affine));
-    if (0==Q)
-        return 0;
+    struct pj_opaque_affine *Q = static_cast<struct pj_opaque_affine *>(pj_calloc(1, sizeof(struct pj_opaque_affine)));
+    if (nullptr==Q)
+        return nullptr;
 
     /* default values */
     Q->forward.s11 = 1.0;
@@ -153,9 +157,9 @@ static void computeReverseParameters(PJ* P)
         if (proj_log_level(P->ctx, PJ_LOG_TELL) >= PJ_LOG_DEBUG) {
             proj_log_debug(P, "Affine: matrix non invertible");
         }
-        P->inv4d = NULL;
-        P->inv3d = NULL;
-        P->inv = NULL;
+        P->inv4d = nullptr;
+        P->inv3d = nullptr;
+        P->inv = nullptr;
     } else {
         Q->reverse.s11 = A / det;
         Q->reverse.s12 = D / det;
@@ -172,7 +176,7 @@ static void computeReverseParameters(PJ* P)
 
 PJ *TRANSFORMATION(affine,0 /* no need for ellipsoid */) {
     struct pj_opaque_affine *Q = initQ();
-    if (0==Q)
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = (void *) Q;
 
@@ -223,7 +227,7 @@ PJ *TRANSFORMATION(affine,0 /* no need for ellipsoid */) {
 
 PJ *TRANSFORMATION(geogoffset,0 /* no need for ellipsoid */) {
     struct pj_opaque_affine *Q = initQ();
-    if (0==Q)
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = (void *) Q;
 
diff --git a/src/PJ_deformation.c b/src/transformations/deformation.cpp
index 5511eed4..6c30f21c 100644
--- a/src/PJ_deformation.c
+++ b/src/transformations/deformation.cpp
@@ -63,11 +63,13 @@ PROJ_HEAD(deformation, "Kinematic grid shift");
 #define TOL 1e-8
 #define MAX_ITERATIONS 10
 
+namespace { // anonymous namespace
 struct pj_opaque {
     double t_obs;
     double t_epoch;
     PJ *cart;
 };
+} // anonymous namespace
 
 /********************************************************************************/
 static XYZ get_grid_shift(PJ* P, XYZ cartesian) {
@@ -86,7 +88,7 @@ static XYZ get_grid_shift(PJ* P, XYZ cartesian) {
     int previous_errno = proj_errno_reset(P);
 
     /* cartesian to geodetic */
-    geodetic.lpz = pj_inv3d(cartesian, P->opaque->cart);
+    geodetic.lpz = pj_inv3d(cartesian, static_cast<struct pj_opaque*>(P->opaque)->cart);
 
     /* look up correction values in grids */
     shift.lp    = proj_hgrid_value(P, geodetic.lp);
@@ -245,15 +247,15 @@ static PJ_COORD reverse_4d(PJ_COORD in, PJ *P) {
     return out;
 }
 
-static void *destructor(PJ *P, int errlev) {
-    if (0==P)
-        return 0;
+static PJ *destructor(PJ *P, int errlev) {
+    if (nullptr==P)
+        return nullptr;
 
-    if (0==P->opaque)
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
 
-    if (P->opaque->cart)
-        P->opaque->cart->destructor (P->opaque->cart, errlev);
+    if (static_cast<struct pj_opaque*>(P->opaque)->cart)
+        static_cast<struct pj_opaque*>(P->opaque)->cart->destructor (static_cast<struct pj_opaque*>(P->opaque)->cart, errlev);
 
     return pj_default_destructor(P, errlev);
 }
@@ -262,13 +264,13 @@ static void *destructor(PJ *P, int errlev) {
 PJ *TRANSFORMATION(deformation,1) {
     int has_xy_grids = 0;
     int has_z_grids  = 0;
-    struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
-    if (0==Q)
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
         return destructor(P, ENOMEM);
     P->opaque = (void *) Q;
 
     Q->cart = proj_create(P->ctx, "+proj=cart");
-    if (Q->cart == 0)
+    if (Q->cart == nullptr)
         return destructor(P, ENOMEM);
 
     /* inherit ellipsoid definition from P to Q->cart */
@@ -311,8 +313,8 @@ PJ *TRANSFORMATION(deformation,1) {
     P->inv4d = reverse_4d;
     P->fwd3d  = forward_3d;
     P->inv3d  = reverse_3d;
-    P->fwd    = 0;
-    P->inv    = 0;
+    P->fwd    = nullptr;
+    P->inv    = nullptr;
 
     P->left  = PJ_IO_UNITS_CARTESIAN;
     P->right = PJ_IO_UNITS_CARTESIAN;
diff --git a/src/PJ_helmert.c b/src/transformations/helmert.cpp
index 757cf950..4a3abf4e 100644
--- a/src/PJ_helmert.c
+++ b/src/transformations/helmert.cpp
@@ -65,6 +65,7 @@ static LPZ helmert_reverse_3d (XYZ xyz, PJ *P);
 
 
 /***********************************************************************/
+namespace { // anonymous namespace
 struct pj_opaque_helmert {
 /************************************************************************
     Projection specific elements for the "helmert" PJ object
@@ -87,6 +88,7 @@ struct pj_opaque_helmert {
     int no_rotation, exact, fourparam;
     int is_position_vector; /* 1 = position_vector, 0 = coordinate_frame */
 };
+} // anonymous namespace
 
 
 /* Make the maths of the rotation operations somewhat more readable and textbook like */
@@ -476,8 +478,8 @@ static PJ_COORD helmert_reverse_4d (PJ_COORD point, PJ *P) {
 
 
 static PJ* init_helmert_six_parameters(PJ* P) {
-    struct pj_opaque_helmert *Q = pj_calloc (1, sizeof (struct pj_opaque_helmert));
-    if (0==Q)
+    struct pj_opaque_helmert *Q = static_cast<struct pj_opaque_helmert*>(pj_calloc (1, sizeof (struct pj_opaque_helmert)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = (void *) Q;
 
@@ -558,7 +560,7 @@ PJ *TRANSFORMATION(helmert, 0) {
     struct pj_opaque_helmert *Q;
 
     if( !init_helmert_six_parameters(P) ) {
-        return 0;
+        return nullptr;
     }
 
     /* In the 2D case, the coordinates are projected */
@@ -661,7 +663,7 @@ PJ *TRANSFORMATION(helmert, 0) {
     }
 
     if( !read_convention(P) ) {
-        return 0;
+        return nullptr;
     }
 
     /* Let's help with debugging */
@@ -697,7 +699,7 @@ PJ *TRANSFORMATION(molobadekas, 0) {
     struct pj_opaque_helmert *Q;
 
     if( !init_helmert_six_parameters(P) ) {
-        return 0;
+        return nullptr;
     }
 
     P->fwd3d  = helmert_forward_3d;
@@ -714,7 +716,7 @@ PJ *TRANSFORMATION(molobadekas, 0) {
     Q->scale  =  Q->scale_0;
 
     if( !read_convention(P) ) {
-        return 0;
+        return nullptr;
     }
 
     /* Reference point */
diff --git a/src/PJ_hgridshift.c b/src/transformations/hgridshift.cpp
index 2919a85c..f0e57251 100644
--- a/src/PJ_hgridshift.c
+++ b/src/transformations/hgridshift.cpp
@@ -10,16 +10,18 @@
 
 PROJ_HEAD(hgridshift, "Horizontal grid shift");
 
+namespace { // anonymous namespace
 struct pj_opaque_hgridshift {
     double t_final;
     double t_epoch;
 };
+} // anonymous namespace
 
 static XYZ forward_3d(LPZ lpz, PJ *P) {
     PJ_COORD point = {{0,0,0,0}};
     point.lpz = lpz;
 
-    if (P->gridlist != NULL) {
+    if (P->gridlist != nullptr) {
         /* Only try the gridshift if at least one grid is loaded,
          * otherwise just pass the coordinate through unchanged. */
         point.lp = proj_hgrid_apply(P, point.lp, PJ_FWD);
@@ -33,7 +35,7 @@ static LPZ reverse_3d(XYZ xyz, PJ *P) {
     PJ_COORD point = {{0,0,0,0}};
     point.xyz = xyz;
 
-    if (P->gridlist != NULL) {
+    if (P->gridlist != nullptr) {
         /* Only try the gridshift if at least one grid is loaded,
          * otherwise just pass the coordinate through unchanged. */
         point.lp = proj_hgrid_apply(P, point.lp, PJ_INV);
@@ -79,8 +81,8 @@ static PJ_COORD reverse_4d(PJ_COORD obs, PJ *P) {
 
 
 PJ *TRANSFORMATION(hgridshift,0) {
-    struct pj_opaque_hgridshift *Q = pj_calloc (1, sizeof (struct pj_opaque_hgridshift));
-    if (0==Q)
+    struct pj_opaque_hgridshift *Q = static_cast<struct pj_opaque_hgridshift*>(pj_calloc (1, sizeof (struct pj_opaque_hgridshift)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = (void *) Q;
 
@@ -88,8 +90,8 @@ PJ *TRANSFORMATION(hgridshift,0) {
     P->inv4d  = reverse_4d;
     P->fwd3d  = forward_3d;
     P->inv3d  = reverse_3d;
-    P->fwd    = 0;
-    P->inv    = 0;
+    P->fwd    = nullptr;
+    P->inv    = nullptr;
 
     P->left  = PJ_IO_UNITS_ANGULAR;
     P->right = PJ_IO_UNITS_ANGULAR;
diff --git a/src/PJ_horner.c b/src/transformations/horner.cpp
index a6a26e52..73977de6 100644
--- a/src/PJ_horner.c
+++ b/src/transformations/horner.cpp
@@ -92,13 +92,7 @@ PROJ_HEAD(horner, "Horner polynomial evaluation");
 #define horner_dealloc(x) pj_dealloc(x)
 #define horner_calloc(n,x) pj_calloc(n,x)
 
-
-struct horner;
-typedef struct horner HORNER;
-static UV      horner (const HORNER *transformation, PJ_DIRECTION direction, UV position);
-static HORNER *horner_alloc (size_t order, int complex_polynomia);
-static void    horner_free (HORNER *h);
-
+namespace { // anonymous namespace
 struct horner {
     int    uneg;     /* u axis negated? */
     int    vneg;     /* v axis negated? */
@@ -118,6 +112,12 @@ struct horner {
     UV *fwd_origin;  /* False longitude/latitude */
     UV *inv_origin;  /* False easting/northing   */
 };
+} // anonymous namespace
+
+typedef struct horner HORNER;
+static UV      horner_func (const HORNER *transformation, PJ_DIRECTION direction, UV position);
+static HORNER *horner_alloc (size_t order, int complex_polynomia);
+static void    horner_free (HORNER *h);
 
 /* e.g. degree = 2: a + bx + cy + dxx + eyy + fxy, i.e. 6 coefficients */
 #define horner_number_of_coefficients(order) \
@@ -141,10 +141,10 @@ static HORNER *horner_alloc (size_t order, int complex_polynomia) {
     /* size_t is unsigned, so we need not check for order > 0 */
     int n = (int)horner_number_of_coefficients(order);
     int polynomia_ok = 0;
-    HORNER *h = horner_calloc (1, sizeof (HORNER));
+    HORNER *h = static_cast<HORNER*>(horner_calloc (1, sizeof (HORNER)));
 
-    if (0==h)
-        return 0;
+    if (nullptr==h)
+        return nullptr;
 
     if (complex_polynomia)
         n = 2*(int)order + 2;
@@ -152,36 +152,36 @@ static HORNER *horner_alloc (size_t order, int complex_polynomia) {
     h->coefs = n;
 
     if (complex_polynomia) {
-        h->fwd_c = horner_calloc (n, sizeof(double));
-        h->inv_c = horner_calloc (n, sizeof(double));
+        h->fwd_c = static_cast<double*>(horner_calloc (n, sizeof(double)));
+        h->inv_c = static_cast<double*>(horner_calloc (n, sizeof(double)));
         if (h->fwd_c && h->inv_c)
             polynomia_ok = 1;
     }
     else {
-        h->fwd_u = horner_calloc (n, sizeof(double));
-        h->fwd_v = horner_calloc (n, sizeof(double));
-        h->inv_u = horner_calloc (n, sizeof(double));
-        h->inv_v = horner_calloc (n, sizeof(double));
+        h->fwd_u = static_cast<double*>(horner_calloc (n, sizeof(double)));
+        h->fwd_v = static_cast<double*>(horner_calloc (n, sizeof(double)));
+        h->inv_u = static_cast<double*>(horner_calloc (n, sizeof(double)));
+        h->inv_v = static_cast<double*>(horner_calloc (n, sizeof(double)));
         if (h->fwd_u && h->fwd_v && h->inv_u && h->inv_v)
             polynomia_ok = 1;
     }
 
-    h->fwd_origin = horner_calloc (1, sizeof(UV));
-    h->inv_origin = horner_calloc (1, sizeof(UV));
+    h->fwd_origin = static_cast<UV*>(horner_calloc (1, sizeof(UV)));
+    h->inv_origin = static_cast<UV*>(horner_calloc (1, sizeof(UV)));
 
     if (polynomia_ok && h->fwd_origin && h->inv_origin)
         return h;
 
     /* safe, since all pointers are null-initialized (by calloc) */
     horner_free (h);
-    return 0;
+    return nullptr;
 }
 
 
 
 
 /**********************************************************************/
-static UV horner (const HORNER *transformation, PJ_DIRECTION direction, UV position) {
+static UV horner_func (const HORNER *transformation, PJ_DIRECTION direction, UV position) {
 /***********************************************************************
 
 A reimplementation of the classic Engsager/Poder 2D Horner polynomial
@@ -226,7 +226,7 @@ summing the tiny high order elements first.
     UV uv_error;
     uv_error.u = uv_error.v = HUGE_VAL;
 
-    if (0==transformation)
+    if (nullptr==transformation)
         return uv_error;
 
     /* Check for valid value of direction (-1, 0, 1) */
@@ -297,12 +297,12 @@ summing the tiny high order elements first.
 
 
 static PJ_COORD horner_forward_4d (PJ_COORD point, PJ *P) {
-    point.uv = horner ((HORNER *) P->opaque, 1, point.uv);
+    point.uv = horner_func ((HORNER *) P->opaque, PJ_FWD, point.uv);
     return point;
 }
 
 static PJ_COORD horner_reverse_4d (PJ_COORD point, PJ *P) {
-    point.uv = horner ((HORNER *) P->opaque, -1, point.uv);
+    point.uv = horner_func ((HORNER *) P->opaque, PJ_INV, point.uv);
     return point;
 }
 
@@ -326,7 +326,7 @@ polynomial evaluation engine.
     UV uv_error;
     uv_error.u = uv_error.v = HUGE_VAL;
 
-    if (0==transformation)
+    if (nullptr==transformation)
         return uv_error;
 
     /* Check for valid value of direction (-1, 0, 1) */
@@ -397,23 +397,23 @@ static PJ_COORD complex_horner_reverse_4d (PJ_COORD point, PJ *P) {
 }
 
 
-static void *horner_freeup (PJ *P, int errlev) {                        /* Destructor */
-    if (0==P)
-        return 0;
-    if (0==P->opaque)
+static PJ *horner_freeup (PJ *P, int errlev) {                        /* Destructor */
+    if (nullptr==P)
+        return nullptr;
+    if (nullptr==P->opaque)
         return pj_default_destructor (P, errlev);
     horner_free ((HORNER *) P->opaque);
-    P->opaque = 0;
+    P->opaque = nullptr;
     return pj_default_destructor (P, errlev);
 }
 
 
-static int parse_coefs (PJ *P, double *coefs, char *param, int ncoefs) {
-    char *buf, *init, *next = 0;
+static int parse_coefs (PJ *P, double *coefs, const char *param, int ncoefs) {
+    char *buf, *init, *next = nullptr;
     int i;
 
-    buf = pj_calloc (strlen (param) + 2, sizeof(char));
-    if (0==buf) {
+    buf = static_cast<char*>(pj_calloc (strlen (param) + 2, sizeof(char)));
+    if (nullptr==buf) {
         proj_log_error (P, "Horner: No memory left");
         return 0;
     }
@@ -429,7 +429,7 @@ static int parse_coefs (PJ *P, double *coefs, char *param, int ncoefs) {
 
     for (i = 0; i < ncoefs; i++) {
         if (i > 0) {
-            if ( next == 0 || ','!=*next) {
+            if ( next == nullptr || ','!=*next) {
                 proj_log_error (P, "Horner: Malformed polynomium set %s. need %d coefs", param, ncoefs);
                 return 0;
             }
@@ -448,10 +448,10 @@ PJ *PROJECTION(horner) {
     HORNER *Q;
     P->fwd4d  = horner_forward_4d;
     P->inv4d  = horner_reverse_4d;
-    P->fwd3d  =  0;
-    P->inv3d  =  0;
-    P->fwd    =  0;
-    P->inv    =  0;
+    P->fwd3d  =  nullptr;
+    P->inv3d  =  nullptr;
+    P->fwd    =  nullptr;
+    P->inv    =  nullptr;
     P->left   =  P->right  =  PJ_IO_UNITS_PROJECTED;
     P->destructor = horner_freeup;
 
@@ -472,9 +472,9 @@ PJ *PROJECTION(horner) {
 		complex_polynomia = 1;
 
     Q = horner_alloc (degree, complex_polynomia);
-    if (Q == 0)
+    if (Q == nullptr)
         return horner_freeup (P, ENOMEM);
-    P->opaque = (void *) Q;
+    P->opaque = Q;
 
     if (complex_polynomia) {
         /* Westings and/or southings? */
diff --git a/src/PJ_molodensky.c b/src/transformations/molodensky.cpp
index dbc83768..91743fda 100644
--- a/src/PJ_molodensky.c
+++ b/src/transformations/molodensky.cpp
@@ -56,6 +56,7 @@ PROJ_HEAD(molodensky, "Molodensky transform");
 static XYZ forward_3d(LPZ lpz, PJ *P);
 static LPZ reverse_3d(XYZ xyz, PJ *P);
 
+namespace { // anonymous namespace
 struct pj_opaque_molodensky {
     double dx;
     double dy;
@@ -64,6 +65,7 @@ struct pj_opaque_molodensky {
     double df;
     int    abridged;
 };
+} // anonymous namespace
 
 
 static double RN (double a, double es, double phi) {
@@ -273,8 +275,8 @@ static PJ_COORD reverse_4d(PJ_COORD obs, PJ *P) {
 
 PJ *TRANSFORMATION(molodensky,1) {
     int count_required_params = 0;
-    struct pj_opaque_molodensky *Q = pj_calloc(1, sizeof(struct pj_opaque_molodensky));
-    if (0==Q)
+    struct pj_opaque_molodensky *Q = static_cast<struct pj_opaque_molodensky*>(pj_calloc(1, sizeof(struct pj_opaque_molodensky)));
+    if (nullptr==Q)
         return pj_default_destructor(P, ENOMEM);
     P->opaque = (void *) Q;
 
diff --git a/src/PJ_vgridshift.c b/src/transformations/vgridshift.cpp
index ac5d26ef..b3da906d 100644
--- a/src/PJ_vgridshift.c
+++ b/src/transformations/vgridshift.cpp
@@ -10,18 +10,20 @@
 
 PROJ_HEAD(vgridshift, "Vertical grid shift");
 
+namespace { // anonymous namespace
 struct pj_opaque_vgridshift {
     double t_final;
     double t_epoch;
     double forward_multiplier;
 };
+} // anonymous namespace
 
 static XYZ forward_3d(LPZ lpz, PJ *P) {
     struct pj_opaque_vgridshift *Q = (struct pj_opaque_vgridshift *) P->opaque;
     PJ_COORD point = {{0,0,0,0}};
     point.lpz = lpz;
 
-    if (P->vgridlist_geoid != NULL) {
+    if (P->vgridlist_geoid != nullptr) {
         /* Only try the gridshift if at least one grid is loaded,
          * otherwise just pass the coordinate through unchanged. */
         point.xyz.z += Q->forward_multiplier * proj_vgrid_value(P, point.lp);
@@ -36,7 +38,7 @@ static LPZ reverse_3d(XYZ xyz, PJ *P) {
     PJ_COORD point = {{0,0,0,0}};
     point.xyz = xyz;
 
-    if (P->vgridlist_geoid != NULL) {
+    if (P->vgridlist_geoid != nullptr) {
         /* Only try the gridshift if at least one grid is loaded,
          * otherwise just pass the coordinate through unchanged. */
         point.xyz.z -= Q->forward_multiplier * proj_vgrid_value(P, point.lp);
@@ -83,8 +85,8 @@ static PJ_COORD reverse_4d(PJ_COORD obs, PJ *P) {
 
 
 PJ *TRANSFORMATION(vgridshift,0) {
-    struct pj_opaque_vgridshift *Q = pj_calloc (1, sizeof (struct pj_opaque_vgridshift));
-    if (0==Q)
+    struct pj_opaque_vgridshift *Q = static_cast<struct pj_opaque_vgridshift*>(pj_calloc (1, sizeof (struct pj_opaque_vgridshift)));
+    if (nullptr==Q)
         return pj_default_destructor (P, ENOMEM);
     P->opaque = (void *) Q;
 
@@ -132,8 +134,8 @@ PJ *TRANSFORMATION(vgridshift,0) {
     P->inv4d = reverse_4d;
     P->fwd3d  = forward_3d;
     P->inv3d  = reverse_3d;
-    P->fwd    = 0;
-    P->inv    = 0;
+    P->fwd    = nullptr;
+    P->inv    = nullptr;
 
     P->left  = PJ_IO_UNITS_ANGULAR;
     P->right = PJ_IO_UNITS_ANGULAR;
diff --git a/src/pj_tsfn.c b/src/tsfn.cpp
index ea3b896d..ea3b896d 100644
--- a/src/pj_tsfn.c
+++ b/src/tsfn.cpp
diff --git a/src/pj_units.c b/src/units.cpp
index 877758a3..50f11396 100644
--- a/src/pj_units.c
+++ b/src/units.cpp
@@ -33,7 +33,7 @@ pj_units[] = {
     {"ind-yd",  "0.91439523",           "Indian Yard",                  0.91439523},
     {"ind-ft",  "0.30479841",           "Indian Foot",                  0.30479841},
     {"ind-ch",  "20.11669506",          "Indian Chain",                 20.11669506},
-    {NULL,      NULL,                   NULL,                           0.0}
+    {nullptr,      nullptr,                   nullptr,                           0.0}
 };
 
 const PJ_UNITS *proj_list_units()
@@ -49,7 +49,7 @@ pj_angular_units[] = {
     {"rad",         "1.0",                   "Radian", 1.0},
     {"deg",         "0.017453292519943296",  "Degree", DEG_TO_RAD},
     {"grad",        "0.015707963267948967",  "Grad",   GRAD_TO_RAD},
-    {NULL,          NULL,                     NULL,    0.0}
+    {nullptr,          nullptr,                     nullptr,    0.0}
 };
 
 const PJ_UNITS *proj_list_angular_units()
diff --git a/src/pj_utils.c b/src/utils.cpp
index 81a80b45..8587dc30 100644
--- a/src/pj_utils.c
+++ b/src/utils.cpp
@@ -43,7 +43,7 @@
 int pj_is_latlong( PJ *pj )
 
 {
-    return pj == NULL || pj->is_latlong;
+    return pj == nullptr || pj->is_latlong;
 }
 
 /************************************************************************/
@@ -55,7 +55,7 @@ int pj_is_latlong( PJ *pj )
 int pj_is_geocent( PJ *pj )
 
 {
-    return pj != NULL && pj->is_geocent;
+    return pj != nullptr && pj->is_geocent;
 }
 
 /************************************************************************/
@@ -118,7 +118,7 @@ PJ *pj_latlong_from_proj( PJ *pj_in )
     {
         pj_ctx_set_errno( pj_in->ctx, PJD_ERR_MAJOR_AXIS_NOT_GIVEN );
 
-        return NULL;
+        return nullptr;
     }
 
     if( !got_datum )
diff --git a/src/vector1.c b/src/vector1.cpp
index 22e1f5d0..869dd76a 100644
--- a/src/vector1.c
+++ b/src/vector1.cpp
@@ -15,14 +15,14 @@ freev2(void **v, int nrows) {
 vector2(int nrows, int ncols, int size) {
 	void **s;
 
-	if ((s = (void **)pj_malloc(sizeof(void *) * nrows)) != NULL) {
+	if ((s = (void **)pj_malloc(sizeof(void *) * nrows)) != nullptr) {
 		int rsize, i;
 
 		rsize = size * ncols;
 		for (i = 0; i < nrows; ++i)
 			if (!(s[i] = pj_malloc(rsize))) {
 				freev2(s, i);
-				return (void **)0;
+				return (void **)nullptr;
 			}
 	}
 	return s;
diff --git a/src/pj_wkt1_generated_parser.c b/src/wkt1_generated_parser.c
index 91d5e60d..7a590f80 100644
--- a/src/pj_wkt1_generated_parser.c
+++ b/src/wkt1_generated_parser.c
@@ -97,7 +97,7 @@
  * DEALINGS IN THE SOFTWARE.
  ****************************************************************************/
 
-#include "pj_wkt1_parser.h"
+#include "wkt1_parser.h"
 
 
 
@@ -119,9 +119,9 @@
 #endif
 
 /* In a future release of Bison, this section will be replaced
-   by #include "pj_wkt1_generated_parser.h".  */
-#ifndef YY_PJ_WKT1_SRC_PJ_WKT1_GENERATED_PARSER_H_INCLUDED
-# define YY_PJ_WKT1_SRC_PJ_WKT1_GENERATED_PARSER_H_INCLUDED
+   by #include "wkt1_generated_parser.h".  */
+#ifndef YY_PJ_WKT1_SRC_WKT1_GENERATED_PARSER_H_INCLUDED
+# define YY_PJ_WKT1_SRC_WKT1_GENERATED_PARSER_H_INCLUDED
 /* Debug traces.  */
 #ifndef YYDEBUG
 # define YYDEBUG 0
@@ -176,7 +176,7 @@ typedef int YYSTYPE;
 
 int pj_wkt1_parse (pj_wkt1_parse_context *context);
 
-#endif /* !YY_PJ_WKT1_SRC_PJ_WKT1_GENERATED_PARSER_H_INCLUDED  */
+#endif /* !YY_PJ_WKT1_SRC_WKT1_GENERATED_PARSER_H_INCLUDED  */
 
 /* Copy the second part of user declarations.  */
 
diff --git a/src/pj_wkt1_generated_parser.h b/src/wkt1_generated_parser.h
index 7bdec61f..989f1f32 100644
--- a/src/pj_wkt1_generated_parser.h
+++ b/src/wkt1_generated_parser.h
@@ -30,8 +30,8 @@
    This special exception was added by the Free Software Foundation in
    version 2.2 of Bison.  */
 
-#ifndef YY_PJ_WKT1_SRC_PJ_WKT1_GENERATED_PARSER_H_INCLUDED
-# define YY_PJ_WKT1_SRC_PJ_WKT1_GENERATED_PARSER_H_INCLUDED
+#ifndef YY_PJ_WKT1_SRC_WKT1_GENERATED_PARSER_H_INCLUDED
+# define YY_PJ_WKT1_SRC_WKT1_GENERATED_PARSER_H_INCLUDED
 /* Debug traces.  */
 #ifndef YYDEBUG
 # define YYDEBUG 0
@@ -86,4 +86,4 @@ typedef int YYSTYPE;
 
 int pj_wkt1_parse (pj_wkt1_parse_context *context);
 
-#endif /* !YY_PJ_WKT1_SRC_PJ_WKT1_GENERATED_PARSER_H_INCLUDED  */
+#endif /* !YY_PJ_WKT1_SRC_WKT1_GENERATED_PARSER_H_INCLUDED  */
diff --git a/src/pj_wkt1_grammar.y b/src/wkt1_grammar.y
index 05ae792a..28ff7a6e 100644
--- a/src/pj_wkt1_grammar.y
+++ b/src/wkt1_grammar.y
@@ -26,7 +26,7 @@
  * DEALINGS IN THE SOFTWARE.
  ****************************************************************************/
 
-#include "pj_wkt1_parser.h"
+#include "wkt1_parser.h"
 
 %}
 
diff --git a/src/pj_wkt1_parser.cpp b/src/wkt1_parser.cpp
index cdeb6b87..9db7d4bd 100644
--- a/src/pj_wkt1_parser.cpp
+++ b/src/wkt1_parser.cpp
@@ -35,8 +35,8 @@
 #include <cstring>
 #include <string>
 
-#include "pj_wkt1_parser.h"
-#include "pj_wkt_parser.hpp"
+#include "wkt1_parser.h"
+#include "wkt_parser.hpp"
 
 using namespace NS_PROJ::internal;
 
diff --git a/src/pj_wkt1_parser.h b/src/wkt1_parser.h
index f8f7c841..f04ee67f 100644
--- a/src/pj_wkt1_parser.h
+++ b/src/wkt1_parser.h
@@ -36,7 +36,7 @@ extern "C" {
 
 typedef struct pj_wkt1_parse_context pj_wkt1_parse_context;
 
-#include "pj_wkt1_generated_parser.h"
+#include "wkt1_generated_parser.h"
 
 void pj_wkt1_error( pj_wkt1_parse_context *context, const char *msg );
 int pj_wkt1_lex(YYSTYPE* pNode, pj_wkt1_parse_context *context);
diff --git a/src/pj_wkt2_generated_parser.c b/src/wkt2_generated_parser.c
index 759ad052..6d816135 100644
--- a/src/pj_wkt2_generated_parser.c
+++ b/src/wkt2_generated_parser.c
@@ -97,7 +97,7 @@
  * DEALINGS IN THE SOFTWARE.
  ****************************************************************************/
 
-#include "pj_wkt2_parser.h"
+#include "wkt2_parser.h"
 
 
 
@@ -119,9 +119,9 @@
 #endif
 
 /* In a future release of Bison, this section will be replaced
-   by #include "pj_wkt2_generated_parser.h".  */
-#ifndef YY_PJ_WKT2_SRC_PJ_WKT2_GENERATED_PARSER_H_INCLUDED
-# define YY_PJ_WKT2_SRC_PJ_WKT2_GENERATED_PARSER_H_INCLUDED
+   by #include "wkt2_generated_parser.h".  */
+#ifndef YY_PJ_WKT2_SRC_WKT2_GENERATED_PARSER_H_INCLUDED
+# define YY_PJ_WKT2_SRC_WKT2_GENERATED_PARSER_H_INCLUDED
 /* Debug traces.  */
 #ifndef YYDEBUG
 # define YYDEBUG 0
@@ -295,7 +295,7 @@ typedef int YYSTYPE;
 
 int pj_wkt2_parse (pj_wkt2_parse_context *context);
 
-#endif /* !YY_PJ_WKT2_SRC_PJ_WKT2_GENERATED_PARSER_H_INCLUDED  */
+#endif /* !YY_PJ_WKT2_SRC_WKT2_GENERATED_PARSER_H_INCLUDED  */
 
 /* Copy the second part of user declarations.  */
 
diff --git a/src/pj_wkt2_generated_parser.h b/src/wkt2_generated_parser.h
index f9d17ea0..baeb0b4f 100644
--- a/src/pj_wkt2_generated_parser.h
+++ b/src/wkt2_generated_parser.h
@@ -30,8 +30,8 @@
    This special exception was added by the Free Software Foundation in
    version 2.2 of Bison.  */
 
-#ifndef YY_PJ_WKT2_SRC_PJ_WKT2_GENERATED_PARSER_H_INCLUDED
-# define YY_PJ_WKT2_SRC_PJ_WKT2_GENERATED_PARSER_H_INCLUDED
+#ifndef YY_PJ_WKT2_SRC_WKT2_GENERATED_PARSER_H_INCLUDED
+# define YY_PJ_WKT2_SRC_WKT2_GENERATED_PARSER_H_INCLUDED
 /* Debug traces.  */
 #ifndef YYDEBUG
 # define YYDEBUG 0
@@ -205,4 +205,4 @@ typedef int YYSTYPE;
 
 int pj_wkt2_parse (pj_wkt2_parse_context *context);
 
-#endif /* !YY_PJ_WKT2_SRC_PJ_WKT2_GENERATED_PARSER_H_INCLUDED  */
+#endif /* !YY_PJ_WKT2_SRC_WKT2_GENERATED_PARSER_H_INCLUDED  */
diff --git a/src/pj_wkt2_grammar.y b/src/wkt2_grammar.y
index 2c8393e2..f028eb5b 100644
--- a/src/pj_wkt2_grammar.y
+++ b/src/wkt2_grammar.y
@@ -26,7 +26,7 @@
  * DEALINGS IN THE SOFTWARE.
  ****************************************************************************/
 
-#include "pj_wkt2_parser.h"
+#include "wkt2_parser.h"
 
 %}
 
diff --git a/src/pj_wkt2_parser.cpp b/src/wkt2_parser.cpp
index 0e898436..f77c7ceb 100644
--- a/src/pj_wkt2_parser.cpp
+++ b/src/wkt2_parser.cpp
@@ -36,8 +36,8 @@
 #include <cstring>
 #include <string>
 
-#include "pj_wkt2_parser.h"
-#include "pj_wkt_parser.hpp"
+#include "wkt2_parser.h"
+#include "wkt_parser.hpp"
 
 using namespace NS_PROJ::internal;
 
diff --git a/src/pj_wkt2_parser.h b/src/wkt2_parser.h
index 9229f2ff..1eaadab6 100644
--- a/src/pj_wkt2_parser.h
+++ b/src/wkt2_parser.h
@@ -36,7 +36,7 @@ extern "C" {
 
 typedef struct pj_wkt2_parse_context pj_wkt2_parse_context;
 
-#include "pj_wkt2_generated_parser.h"
+#include "wkt2_generated_parser.h"
 
 void pj_wkt2_error( pj_wkt2_parse_context *context, const char *msg );
 int pj_wkt2_lex(YYSTYPE* pNode, pj_wkt2_parse_context *context);
diff --git a/src/pj_wkt_parser.cpp b/src/wkt_parser.cpp
index ea8d2a29..32fc4e34 100644
--- a/src/pj_wkt_parser.cpp
+++ b/src/wkt_parser.cpp
@@ -25,7 +25,7 @@
  * DEALINGS IN THE SOFTWARE.
  ****************************************************************************/
 
-#include "pj_wkt_parser.hpp"
+#include "wkt_parser.hpp"
 
 #include <algorithm>
 #include <string>
diff --git a/src/pj_wkt_parser.hpp b/src/wkt_parser.hpp
index 0e7e9e8b..0e7e9e8b 100644
--- a/src/pj_wkt_parser.hpp
+++ b/src/wkt_parser.hpp
diff --git a/src/pj_zpoly1.c b/src/zpoly1.cpp
index bacb62ce..bacb62ce 100644
--- a/src/pj_zpoly1.c
+++ b/src/zpoly1.cpp