Merge pull request #674 from aaronpuchert/const-globals

Declare non-local variables as const where possible

34 files changed, 130 insertions, 117 deletions

diff --git a/src/PJ_healpix.c b/src/PJ_healpix.c
index 41f62ee4..2d62050c 100644
--- a/src/PJ_healpix.c
+++ b/src/PJ_healpix.c
@@ -64,7 +64,7 @@ typedef struct {
     enum Region {north, south, equatorial} region;
 } CapMap;
 
-double rot[7][2][2] = ROT;
+static const double rot[7][2][2] = ROT;
 
 /**
  * Returns the sign of the double.
@@ -310,7 +310,7 @@ static LP healpix_sphere_inverse(XY xy) {
  * Return the vector sum a + b, where a and b are 2-dimensional vectors.
  * @param ret holds a + b.
  **/
-static void vector_add(double a[2], double b[2], double *ret) {
+static void vector_add(const double a[2], const double b[2], double *ret) {
     int i;
     for(i = 0; i < 2; i++) {
         ret[i] = a[i] + b[i];
@@ -322,7 +322,7 @@ static void vector_add(double a[2], double b[2], double *ret) {
  * Return the vector difference a - b, where a and b are 2-dimensional vectors.
  * @param ret holds a - b.
  **/
-static void vector_sub(double a[2], double b[2], double*ret) {
+static void vector_sub(const double a[2], const double b[2], double*ret) {
     int i;
     for(i = 0; i < 2; i++) {
         ret[i] = a[i] - b[i];
@@ -335,7 +335,7 @@ static void vector_sub(double a[2], double b[2], double*ret) {
  * b is a 2 x 1 matrix.
  * @param ret holds a*b.
  **/
-static void dot_product(double a[2][2], double b[2], double *ret) {
+static void dot_product(const double a[2][2], const double b[2], double *ret) {
     int i, j;
     int length = 2;
     for(i = 0; i < length; i++) {
@@ -453,7 +453,7 @@ static XY combine_caps(double x, double y, int north_square, int south_square,
     double vector[2];
     double v_min_c[2];
     double ret_dot[2];
-    double (*tmpRot)[2];
+    const double (*tmpRot)[2];
     int pole = 0;
 
     CapMap capmap = get_cap(x, y, north_square, south_square, inverse);
diff --git a/src/PJ_isea.c b/src/PJ_isea.c
index bf006a62..9baea8b5 100644
--- a/src/PJ_isea.c
+++ b/src/PJ_isea.c
@@ -159,7 +159,7 @@ struct snyder_constants {
 };
 
 /* TODO put these in radians to avoid a later conversion */
-ISEA_STATIC
+ISEA_STATIC const
 struct snyder_constants constants[] = {
     {23.80018260, 62.15458023, 60.0, 3.75, 1.033, 0.968, 5.09, 1.195, 1.0},
     {20.07675127, 55.69063953, 54.0, 2.65, 1.030, 0.983, 3.59, 1.141, 1.027},
@@ -217,7 +217,7 @@ static int      tri_v1[] = {0, 0, 0, 0, 0, 0, 6, 7, 8, 9, 10, 2, 3, 4, 5, 1, 11,
 #define F_RAD 0.18871053072122403508
 
 /* triangle Centers */
-struct isea_geo icostriangles[] = {
+static const struct isea_geo icostriangles[] = {
     {0.0, 0.0},
     {-DEG144, E_RAD},
     {-DEG72, E_RAD},
diff --git a/src/PJ_mod_ster.c b/src/PJ_mod_ster.c
index c8e4c6b8..d807660c 100644
--- a/src/PJ_mod_ster.c
+++ b/src/PJ_mod_ster.c
@@ -12,7 +12,7 @@ PROJ_HEAD(gs50, "Mod. Stereographic of 50 U.S.") "\n\tAzi(mod)";
 #define EPSLN 1e-12
 
 struct pj_opaque {
-    COMPLEX *zcoeff; \
+    const COMPLEX *zcoeff; \
     double  cchio, schio; \
     int     n;
 };
@@ -120,7 +120,7 @@ static PJ *setup(PJ *P) { /* general initialization */
 
 /* Miller Oblated Stereographic */
 PJ *PROJECTION(mil_os) {
-    static COMPLEX AB[] = {
+    static const COMPLEX AB[] = {
         {0.924500, 0.},
         {0.,       0.},
         {0.019430, 0.}
@@ -143,7 +143,7 @@ PJ *PROJECTION(mil_os) {
 
 /* Lee Oblated Stereographic */
 PJ *PROJECTION(lee_os) {
-    static COMPLEX AB[] = {
+    static const COMPLEX AB[] = {
         {0.721316,    0.},
         {0.,          0.},
         {-0.0088162, -0.00617325}
@@ -165,7 +165,7 @@ PJ *PROJECTION(lee_os) {
 
 
 PJ *PROJECTION(gs48) {
-    static COMPLEX /* 48 United States */
+    static const COMPLEX /* 48 United States */
     AB[] = {
         {0.98879,   0.},
         {0.,        0.},
@@ -191,7 +191,7 @@ PJ *PROJECTION(gs48) {
 
 
 PJ *PROJECTION(alsk) {
-    static COMPLEX  ABe[] = { /* Alaska ellipsoid */
+    static const COMPLEX  ABe[] = { /* Alaska ellipsoid */
         { .9945303, 0.},
         { .0052083, -.0027404},
         { .0072721,  .0048181},
@@ -200,7 +200,7 @@ PJ *PROJECTION(alsk) {
         { .3582802, -.2884586},
     };
 
-    static COMPLEX ABs[] = { /* Alaska sphere */
+    static const COMPLEX ABs[] = { /* Alaska sphere */
         { .9972523, 0.},
         { .0052513, -.0041175},
         { .0074606,  .0048125},
@@ -231,7 +231,7 @@ PJ *PROJECTION(alsk) {
 
 
 PJ *PROJECTION(gs50) {
-    static COMPLEX  ABe[] = { /* GS50 ellipsoid */
+    static const COMPLEX  ABe[] = { /* GS50 ellipsoid */
         { .9827497, 0.},
         { .0210669,  .0053804},
         {-.1031415, -.0571664},
@@ -244,7 +244,7 @@ PJ *PROJECTION(gs50) {
         {-.0210072,  .0834037}
     };
 
-    static COMPLEX ABs[] = { /* GS50 sphere */
+    static const COMPLEX ABs[] = { /* GS50 sphere */
         { .9842990, 0.},
         { .0211642,  .0037608},
         {-.1036018, -.0575102},
diff --git a/src/PJ_nzmg.c b/src/PJ_nzmg.c
index 2d65a6e1..b30deabf 100644
--- a/src/PJ_nzmg.c
+++ b/src/PJ_nzmg.c
@@ -34,7 +34,7 @@ PROJ_HEAD(nzmg, "New Zealand Map Grid") "\n\tfixed Earth";
 #define SEC5_TO_RAD 0.4848136811095359935899141023
 #define RAD_TO_SEC5 2.062648062470963551564733573
 
-static COMPLEX bf[] = {
+static const COMPLEX bf[] = {
     { .7557853228, 0.0},
     { .249204646,  0.003371507},
     {-.001541739,  0.041058560},
@@ -42,12 +42,12 @@ static COMPLEX bf[] = {
     {-.26623489,  -0.36249218},
     {-.6870983,   -1.1651967} };
 
-static double tphi[] = { 1.5627014243, .5185406398, -.03333098,
-                         -.1052906,   -.0368594,     .007317,
-                          .01220,      .00394,      -.0013 };
+static const double tphi[] = { 1.5627014243, .5185406398, -.03333098,
+                               -.1052906,   -.0368594,     .007317,
+                                .01220,      .00394,      -.0013 };
 
-static double tpsi[] = { .6399175073, -.1358797613, .063294409, -.02526853, .0117879,
-                        -.0055161,     .0026906,   -.001333,     .00067,   -.00034 };
+static const double tpsi[] = { .6399175073, -.1358797613, .063294409, -.02526853, .0117879,
+                              -.0055161,     .0026906,   -.001333,     .00067,   -.00034 };
 
 #define Nbf 5
 #define Ntpsi 9
@@ -57,7 +57,7 @@ static double tpsi[] = { .6399175073, -.1358797613, .063294409, -.02526853, .011
 static XY e_forward (LP lp, PJ *P) {          /* Ellipsoidal, forward */
     XY xy = {0.0,0.0};
     COMPLEX p;
-    double *C;
+    const double *C;
     int i;
 
     lp.phi = (lp.phi - P->phi0) * RAD_TO_SEC5;
@@ -77,7 +77,8 @@ static LP e_inverse (XY xy, PJ *P) {          /* Ellipsoidal, inverse */
     LP lp = {0.0,0.0};
     int nn, i;
     COMPLEX p, f, fp, dp;
-    double den, *C;
+    double den;
+    const double *C;
 
     p.r = xy.y;
     p.i = xy.x;
diff --git a/src/PJ_pipeline.c b/src/PJ_pipeline.c
index a0ef7c1e..2b012193 100644
--- a/src/PJ_pipeline.c
+++ b/src/PJ_pipeline.c
@@ -273,7 +273,7 @@ static size_t argc_params (paralist *params) {
 }
 
 /* Sentinel for argument list */
-static char argv_sentinel[] = "step";
+static char *argv_sentinel = "step";
 
 /* turn paralist into argc/argv style argument list */
 static char **argv_params (paralist *params, size_t argc) {
@@ -363,7 +363,7 @@ PJ *OPERATION(pipeline,0) {
 
     /* Do some syntactical sanity checking */
     for (i = 0;  i < argc;  i++) {
-        if (0==strcmp ("step", argv[i])) {
+        if (0==strcmp (argv_sentinel, argv[i])) {
             if (-1==i_pipeline) {
                 proj_log_error (P, "Pipeline: +step before +proj=pipeline");
                 return destructor (P, PJD_ERR_MALFORMED_PIPELINE);
diff --git a/src/PJ_unitconvert.c b/src/PJ_unitconvert.c
index fc90821b..106caabf 100644
--- a/src/PJ_unitconvert.c
+++ b/src/PJ_unitconvert.c
@@ -256,7 +256,7 @@ static double mjd_to_yyyymmdd(double mjd) {
 }
 
 
-struct TIME_UNITS time_units[] = {
+static const struct TIME_UNITS time_units[] = {
     {"mjd",         mjd_to_mjd,         mjd_to_mjd,         "Modified julian date"},
     {"decimalyear", decimalyear_to_mjd, mjd_to_decimalyear, "Decimal year"},
     {"gps_week",    gps_week_to_mjd,    mjd_to_gps_week,    "GPS Week"},
diff --git a/src/cs2cs.c b/src/cs2cs.c
index 7afeea73..730d37ee 100644
--- a/src/cs2cs.c
+++ b/src/cs2cs.c
@@ -26,6 +26,7 @@
  * DEALINGS IN THE SOFTWARE.
  *****************************************************************************/
 
+#include "proj.h"
 #include "projects.h"
 #include <stdio.h>
 #include <stdlib.h>
@@ -206,11 +207,11 @@ int main(int argc, char **argv)
               case 'l': /* list projections, ellipses or units */
                 if (!arg[1] || arg[1] == 'p' || arg[1] == 'P') {
                     /* list projections */
-                    struct PJ_LIST *lp;
+                    const struct PJ_LIST *lp;
                     int do_long = arg[1] == 'P', c;
                     char *str;
 
-                    for (lp = pj_get_list_ref() ; lp->id ; ++lp) {
+                    for (lp = proj_list_operations() ; lp->id ; ++lp) {
                         (void)printf("%s : ", lp->id);
                         if (do_long)  /* possibly multiline description */
                             (void)puts(*lp->descr);
@@ -222,28 +223,28 @@ int main(int argc, char **argv)
                         }
                     }
                 } else if (arg[1] == '=') { /* list projection 'descr' */
-                    struct PJ_LIST *lp;
+                    const struct PJ_LIST *lp;
 
                     arg += 2;
-                    for (lp = pj_get_list_ref() ; lp->id ; ++lp)
+                    for (lp = proj_list_operations() ; lp->id ; ++lp)
                         if (!strcmp(lp->id, arg)) {
                             (void)printf("%9s : %s\n", lp->id, *lp->descr);
                             break;
                         }
                 } else if (arg[1] == 'e') { /* list ellipses */
-                    struct PJ_ELLPS *le;
+                    const struct PJ_ELLPS *le;
 
-                    for (le = pj_get_ellps_ref(); le->id ; ++le)
+                    for (le = proj_list_ellps(); le->id ; ++le)
                         (void)printf("%9s %-16s %-16s %s\n",
                                      le->id, le->major, le->ell, le->name);
                 } else if (arg[1] == 'u') { /* list units */
-                    struct PJ_UNITS *lu;
+                    const struct PJ_UNITS *lu;
 
-                    for (lu = pj_get_units_ref(); lu->id ; ++lu)
+                    for (lu = proj_list_units(); lu->id ; ++lu)
                         (void)printf("%12s %-20s %s\n",
                                      lu->id, lu->to_meter, lu->name);
                 } else if (arg[1] == 'd') { /* list datums */
-                    struct PJ_DATUMS *ld;
+                    const struct PJ_DATUMS *ld;
 
                     printf("__datum_id__ __ellipse___ __definition/comments______________________________\n" );
                     for (ld = pj_get_datums_ref(); ld->id ; ++ld)
@@ -254,9 +255,9 @@ int main(int argc, char **argv)
                             printf( "%25s %s\n", " ", ld->comments );
                     }
                 } else if( arg[1] == 'm') { /* list prime meridians */
-                    struct PJ_PRIME_MERIDIANS *lpm;
+                    const struct PJ_PRIME_MERIDIANS *lpm;
 
-                    for (lpm = pj_get_prime_meridians_ref(); lpm->id ; ++lpm)
+                    for (lpm = proj_list_prime_meridians(); lpm->id ; ++lpm)
                         (void)printf("%12s %-30s\n",
                                      lpm->id, lpm->defn);
                 } else
diff --git a/src/emess.c b/src/emess.c
index 7b6ebf75..dc4cb824 100644
--- a/src/emess.c
+++ b/src/emess.c
@@ -18,7 +18,7 @@
 #define EMESS_ROUTINE
 #include "emess.h"
 	void
-emess(int code, char *fmt, ...) {
+emess(int code, const char *fmt, ...) {
 	va_list args;
 
 	va_start(args, fmt);
diff --git a/src/emess.h b/src/emess.h
index b694d61e..4a6f7587 100644
--- a/src/emess.h
+++ b/src/emess.h
@@ -24,6 +24,6 @@ extern struct EMESS emess_dat;
 
 #endif /* use type */
 
-void emess(int, char *, ...);
+void emess(int, const char *, ...);
 
 #endif /* end EMESS_H */
diff --git a/src/geod.c b/src/geod.c
index 755afbd7..e90d71b5 100644
--- a/src/geod.c
+++ b/src/geod.c
@@ -1,4 +1,6 @@
 /* <<<< Geodesic filter program >>>> */
+
+#include "proj.h"
 # include "projects.h"
 # include "geod_interface.h"
 # include "emess.h"
@@ -175,15 +177,15 @@ noargument:		   emess(1,"missing argument for -%c",*arg);
 				continue;
 			case 'l':
 				if (!arg[1] || arg[1] == 'e') { /* list of ellipsoids */
-                                    struct PJ_ELLPS *le;
+                                    const struct PJ_ELLPS *le;
                                     
-                                    for (le=pj_get_ellps_ref(); le->id ; ++le)
+                                    for (le=proj_list_ellps(); le->id ; ++le)
                                         (void)printf("%9s %-16s %-16s %s\n",
                                                      le->id, le->major, le->ell, le->name);
 				} else if (arg[1] == 'u') { /* list of units */
-                                    struct PJ_UNITS *lu;
+                                    const struct PJ_UNITS *lu;
                                     
-                                    for (lu = pj_get_units_ref();lu->id ; ++lu)
+                                    for (lu = proj_list_units();lu->id ; ++lu)
                                         (void)printf("%12s %-20s %s\n",
                                                      lu->id, lu->to_meter, lu->name);
 				} else
diff --git a/src/geod_set.c b/src/geod_set.c
index 16396a90..26a86b61 100644
--- a/src/geod_set.c
+++ b/src/geod_set.c
@@ -2,6 +2,7 @@
 #define _IN_GEOD_SET
 
 #include <string.h>
+#include "proj.h"
 #include "projects.h"
 #include "geod_interface.h"
 #include "emess.h"
@@ -29,7 +30,7 @@ geod_set(int argc, char **argv) {
 	/* set units */
 	if ((name = pj_param(NULL,start, "sunits").s) != NULL) {
 		char *s;
-                struct PJ_UNITS *unit_list = pj_get_units_ref();
+                const struct PJ_UNITS *unit_list = proj_list_units();
 		for (i = 0; (s = unit_list[i].id) && strcmp(name, s) ; ++i) ;
 		if (!s)
 			emess(1,"%s unknown unit conversion id", name);
diff --git a/src/geodtest.c b/src/geodtest.c
index 6899436c..5b41b72c 100644
--- a/src/geodtest.c
+++ b/src/geodtest.c
@@ -20,7 +20,7 @@
 #  pragma warning (disable: 4706)
 #endif
 
-double wgs84_a = 6378137, wgs84_f = 1/298.257223563; /* WGS84 */
+static const double wgs84_a = 6378137, wgs84_f = 1/298.257223563; /* WGS84 */
 
 static int assertEquals(double x, double y, double d) {
   if (fabs(x - y) <= d)
@@ -29,8 +29,8 @@ static int assertEquals(double x, double y, double d) {
   return 1;
 }
 
-const int ncases = 20;
-double testcases[20][12] = {
+static const int ncases = 20;
+static const double testcases[20][12] = {
   {35.60777, -139.44815, 111.098748429560326,
    -11.17491, -69.95921, 129.289270889708762,
    8935244.5604818305, 80.50729714281974, 6273170.2055303837,
diff --git a/src/gie.c b/src/gie.c
index e23ca92b..2ae2ddee 100644
--- a/src/gie.c
+++ b/src/gie.c
@@ -199,8 +199,6 @@ static const char delim[] = {"--------------------------------------------------
 
 #define CMDLEN 250000
 
-int nfiles = 0;
-
 
 static const char usage[] = {
     "--------------------------------------------------------------------------------\n"
@@ -1316,7 +1314,7 @@ whitespace etc. The block is stored in G->args. Returns 1 on success, 0 otherwis
 
 
 
-char tc32_utm32[] = {
+static const char tc32_utm32[] = {
     " +proj=horner"
     " +ellps=intl"
     " +range=500000"
@@ -1330,7 +1328,7 @@ char tc32_utm32[] = {
 };
 
 
-char sb_utm32[] = {
+static const char sb_utm32[] = {
     " +proj=horner"
     " +ellps=intl"
     " +range=500000"
diff --git a/src/multistresstest.c b/src/multistresstest.c
index 8e7517ec..e32c7ae4 100644
--- a/src/multistresstest.c
+++ b/src/multistresstest.c
@@ -54,7 +54,7 @@ typedef struct {
     int     skip;
 } TestItem;
 
-TestItem test_list[] = {
+static TestItem test_list[] = {
     {
         "+proj=utm +zone=11 +datum=WGS84",
         "+proj=latlong +datum=WGS84",
diff --git a/src/nad2bin.c b/src/nad2bin.c
index 8401df79..03a55326 100644
--- a/src/nad2bin.c
+++ b/src/nad2bin.c
@@ -13,8 +13,8 @@
 /*      Convert the byte order of the given word(s) in place.           */
 /************************************************************************/
 
-static int  byte_order_test = 1;
-#define IS_LSB	(((unsigned char *) (&byte_order_test))[0] == 1)
+static const int  byte_order_test = 1;
+#define IS_LSB	(((const unsigned char *) (&byte_order_test))[0] == 1)
 
 static void swap_words( void *data_in, int word_size, int word_count )
 
diff --git a/src/nad_init.c b/src/nad_init.c
index 99342aa5..04177a44 100644
--- a/src/nad_init.c
+++ b/src/nad_init.c
@@ -38,8 +38,8 @@
 /*      Convert the byte order of the given word(s) in place.           */
 /************************************************************************/
 
-static int  byte_order_test = 1;
-#define IS_LSB	(((unsigned char *) (&byte_order_test))[0] == 1)
+static const int  byte_order_test = 1;
+#define IS_LSB	(((const unsigned char *) (&byte_order_test))[0] == 1)
 
 static void swap_words( void *data_in, int word_size, int word_count )
 
diff --git a/src/pj_datums.c b/src/pj_datums.c
index c9655cd6..834ce724 100644
--- a/src/pj_datums.c
+++ b/src/pj_datums.c
@@ -25,8 +25,9 @@
  * DEALINGS IN THE SOFTWARE.
  *****************************************************************************/
 
-#define PJ_DATUMS__
+#include "proj.h"
 
+#define PJ_DATUMS__
 #include <projects.h>
 
 /* 
@@ -35,7 +36,7 @@
  * datum name for the comments if available. 
  */
 
-C_NAMESPACE_VAR struct PJ_DATUMS pj_datums[] = {
+C_NAMESPACE_VAR const struct PJ_DATUMS pj_datums[] = {
 /* id       definition                               ellipse  comments */
 /* --       ----------                               -------  -------- */
 {"WGS84",   "towgs84=0,0,0",                         "WGS84", ""},
@@ -65,12 +66,11 @@ C_NAMESPACE_VAR struct PJ_DATUMS pj_datums[] = {
 };
 
 struct PJ_DATUMS *pj_get_datums_ref()
-
 {
-    return pj_datums;
+    return (struct PJ_DATUMS *)pj_datums;
 }
 
-C_NAMESPACE_VAR struct PJ_PRIME_MERIDIANS pj_prime_meridians[] = {
+C_NAMESPACE_VAR const struct PJ_PRIME_MERIDIANS pj_prime_meridians[] = {
     /* id        definition                         */
     /* --        ----------                         */
     {"greenwich", "0dE"},
@@ -90,8 +90,11 @@ C_NAMESPACE_VAR struct PJ_PRIME_MERIDIANS pj_prime_meridians[] = {
 };
 
 struct PJ_PRIME_MERIDIANS *pj_get_prime_meridians_ref()
+{
+    return (struct PJ_PRIME_MERIDIANS *)pj_prime_meridians;
+}
 
+const PJ_PRIME_MERIDIANS *proj_list_prime_meridians(void)
 {
     return pj_prime_meridians;
 }
-
diff --git a/src/pj_ell_set.c b/src/pj_ell_set.c
index d21122e3..ab2fa818 100644
--- a/src/pj_ell_set.c
+++ b/src/pj_ell_set.c
@@ -14,7 +14,7 @@ static int ellps_spherification (PJ *P);
 
 static paralist *pj_get_param (paralist *list, char *key);
 static char     *pj_param_value (paralist *list);
-static PJ_ELLPS *pj_find_ellps (char *name);
+static const PJ_ELLPS *pj_find_ellps (char *name);
 
 
 /***************************************************************************************/
@@ -125,7 +125,7 @@ int pj_ellipsoid (PJ *P) {
 static int ellps_ellps (PJ *P) {
 /***************************************************************************************/
     PJ B;
-    PJ_ELLPS *ellps;
+    const PJ_ELLPS *ellps;
     paralist *par = 0;
     char *name;
     int err;
@@ -419,7 +419,7 @@ static char *pj_param_value (paralist *list) {
 }
 
 
-static PJ_ELLPS *pj_find_ellps (char *name) {
+static const PJ_ELLPS *pj_find_ellps (char *name) {
     int i;
     char *s;
     if (0==name)
diff --git a/src/pj_ellps.c b/src/pj_ellps.c
index 2a2c5d3b..af5990dd 100644
--- a/src/pj_ellps.c
+++ b/src/pj_ellps.c
@@ -1,8 +1,11 @@
 /* definition of standard geoids */
+
+#include "proj.h"
+
 #define PJ_ELLPS__
 #include "projects.h"
 
-C_NAMESPACE_VAR struct PJ_ELLPS
+C_NAMESPACE_VAR const struct PJ_ELLPS
 pj_ellps[] = {
 {"MERIT",	"a=6378137.0",		"rf=298.257",		"MERIT 1983"},
 {"SGS85",	"a=6378136.0",		"rf=298.257",		"Soviet Geodetic System 85"},
@@ -53,7 +56,11 @@ pj_ellps[] = {
 };
 
 struct PJ_ELLPS *pj_get_ellps_ref()
+{
+    return (struct PJ_ELLPS *)pj_ellps;
+}
 
+const PJ_ELLPS *proj_list_ellps(void)
 {
     return pj_ellps;
 }
diff --git a/src/pj_gauss.c b/src/pj_gauss.c
index 41ee8abf..bd49b6c2 100644
--- a/src/pj_gauss.c
+++ b/src/pj_gauss.c
@@ -65,7 +65,7 @@ void *pj_gauss_ini(double e, double phi0, double *chi, double *rc) {
 }
 
 LP pj_gauss(projCtx ctx, LP elp, const void *data) {
-    struct GAUSS *en = (struct GAUSS *)data;
+    const struct GAUSS *en = (const struct GAUSS *)data;
     LP slp;
     (void) ctx;
 
@@ -77,7 +77,7 @@ LP pj_gauss(projCtx ctx, LP elp, const void *data) {
 }
 
 LP pj_inv_gauss(projCtx ctx, LP slp, const void *data) {
-    struct GAUSS *en = (struct GAUSS *)data;
+    const struct GAUSS *en = (const struct GAUSS *)data;
     LP elp;
     double num;
     int i;
diff --git a/src/pj_gc_reader.c b/src/pj_gc_reader.c
index e49e56a4..90610a17 100644
--- a/src/pj_gc_reader.c
+++ b/src/pj_gc_reader.c
@@ -47,7 +47,7 @@ PJ_GridCatalog *pj_gc_readcatalog( projCtx ctx, const char *catalog_name )
     int entry_max;
     char line[302];
     
-    fid = pj_open_lib( ctx, (char *) catalog_name, "r" );
+    fid = pj_open_lib( ctx, catalog_name, "r" );
     if (fid == NULL) 
         return NULL;
 
diff --git a/src/pj_gridinfo.c b/src/pj_gridinfo.c
index 9b9a8d82..b1b39e01 100644
--- a/src/pj_gridinfo.c
+++ b/src/pj_gridinfo.c
@@ -40,8 +40,8 @@
 /*      Convert the byte order of the given word(s) in place.           */
 /************************************************************************/
 
-static int  byte_order_test = 1;
-#define IS_LSB	(1 == ((unsigned char *) (&byte_order_test))[0])
+static const int  byte_order_test = 1;
+#define IS_LSB	(1 == ((const unsigned char *) (&byte_order_test))[0])
 
 static void swap_words( unsigned char *data, int word_size, int word_count )
 
diff --git a/src/pj_init.c b/src/pj_init.c
index 8f4eb477..7e885575 100644
--- a/src/pj_init.c
+++ b/src/pj_init.c
@@ -639,7 +639,7 @@ pj_init_ctx(projCtx ctx, int argc, char **argv) {
     /* Axis orientation */
     if( (pj_param(ctx, start,"saxis").s) != NULL )
     {
-        static const char *axis_legal = "ewnsud";
+        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);
diff --git a/src/pj_list.c b/src/pj_list.c
index 2bdd3053..d34e055d 100644
--- a/src/pj_list.c
+++ b/src/pj_list.c
@@ -2,6 +2,8 @@
 ** Use local definition of PJ_LIST_H for subset.
 */
 
+#include "proj.h"
+
 #define USE_PJ_LIST_H 1
 #include "projects.h"
 
@@ -18,13 +20,18 @@
 
 /* Generate the null-terminated list of projection functions with associated mnemonics and descriptions */
 #define PROJ_HEAD(id, name) {#id, pj_##id, &pj_s_##id},
-struct PJ_LIST pj_list[] = {
+const struct PJ_LIST pj_list[] = {
 #include "pj_list.h"
 		{0,     0,  0},
 	};
 #undef PROJ_HEAD
 
 
-struct PJ_LIST  *pj_get_list_ref (void) {
+struct PJ_LIST *pj_get_list_ref()
+{
+    return (struct PJ_LIST *)pj_list;
+}
+
+const PJ_OPERATIONS *proj_list_operations(void) {
     return pj_list;
 }
diff --git a/src/pj_open_lib.c b/src/pj_open_lib.c
index 08532beb..4eaefba1 100644
--- a/src/pj_open_lib.c
+++ b/src/pj_open_lib.c
@@ -38,7 +38,7 @@
 static const char *(*pj_finder)(const char *) = NULL;
 static int path_count = 0;
 static char **search_path = NULL;
-static char * proj_lib_name =
+static const char * proj_lib_name =
 #ifdef PROJ_LIB
 PROJ_LIB;
 #else
@@ -93,8 +93,8 @@ void pj_set_searchpath ( int count, const char **path )
 
 /* just a couple of helper functions that lets other functions
    access the otherwise private search path */
-const char **proj_get_searchpath(void) {
-    return (const char **)search_path;
+const char * const *proj_get_searchpath(void) {
+    return (const char * const *)search_path;
 }
 
 int proj_get_path_count(void) {
diff --git a/src/pj_strerrno.c b/src/pj_strerrno.c
index 3e726895..c2221e58 100644
--- a/src/pj_strerrno.c
+++ b/src/pj_strerrno.c
@@ -4,7 +4,7 @@
 #include <errno.h>
 #include <string.h>
 
-    static char *
+    static const char * const
 pj_err_list[] = {
     "no arguments in initialization list",                             /*  -1 */
     "no options found in 'init' file",                                 /*  -2 */
@@ -91,7 +91,7 @@ char *pj_strerrno(int err) {
     /* PROJ.4 error codes are negative */
     adjusted_err = - err - 1;
     if (adjusted_err < (sizeof(pj_err_list) / sizeof(char *)))
-        return(pj_err_list[adjusted_err]);
+        return (char *)pj_err_list[adjusted_err];
 
     sprintf( note, "invalid projection system error (%d)", (err > -9999)? err: -9999);
     return note;
diff --git a/src/pj_units.c b/src/pj_units.c
index 7dbae34c..fe4ad453 100644
--- a/src/pj_units.c
+++ b/src/pj_units.c
@@ -1,10 +1,14 @@
 /* definition of standard cartesian units */
+
+#include "proj.h"
+
 #define PJ_UNITS__
 #include <projects.h>
+
 /* Field 2 that contains the multiplier to convert named units to meters
 ** may be expressed by either a simple floating point constant or a
 ** numerator/denomenator values (e.g. 1/1000) */
-C_NAMESPACE_VAR struct PJ_UNITS
+C_NAMESPACE_VAR const struct PJ_UNITS
 pj_units[] = {
     {"km",      "1000.",                "Kilometer",                    1000.0},
     {"m",       "1.",                   "Meter",                        1.0},
@@ -31,7 +35,11 @@ pj_units[] = {
 };
 
 struct PJ_UNITS *pj_get_units_ref()
+{
+    return (struct PJ_UNITS *)pj_units;
+}
 
+const PJ_UNITS *proj_list_units()
 {
     return pj_units;
 }
diff --git a/src/pj_zpoly1.c b/src/pj_zpoly1.c
index 3d6418bb..626a1fed 100644
--- a/src/pj_zpoly1.c
+++ b/src/pj_zpoly1.c
@@ -5,7 +5,7 @@
 **	n should always be >= 1 though no checks are made
 */
 	COMPLEX
-pj_zpoly1(COMPLEX z, COMPLEX *C, int n) {
+pj_zpoly1(COMPLEX z, const COMPLEX *C, int n) {
 	COMPLEX a;
 	double t;
 
@@ -20,7 +20,7 @@ pj_zpoly1(COMPLEX z, COMPLEX *C, int n) {
 }
 /* evaluate complex polynomial and derivative */
 	COMPLEX
-pj_zpolyd1(COMPLEX z, COMPLEX *C, int n, COMPLEX *der) {
+pj_zpolyd1(COMPLEX z, const COMPLEX *C, int n, COMPLEX *der) {
 	COMPLEX a, b;
 	double t;
 	int first = 1;
diff --git a/src/proj.c b/src/proj.c
index 7922a5ac..1d702ea4 100644
--- a/src/proj.c
+++ b/src/proj.c
@@ -45,7 +45,9 @@ static int
 
 static char
     *cheby_str,         /* string controlling Chebychev evaluation */
-    *oform = (char *)0, /* output format for x-y or decimal degrees */
+    *oform = (char *)0; /* output format for x-y or decimal degrees */
+
+static const char
     *oterr = "*\t*",    /* output line for unprojectable input */
     *usage = "%s\nusage: %s [ -beEfiIlormsStTvVwW [args] ] [ +opts[=arg] ] [ files ]\n";
 
@@ -356,11 +358,11 @@ int main(int argc, char **argv) {
               case 'l': /* list projections, ellipses or units */
                 if (!arg[1] || arg[1] == 'p' || arg[1] == 'P') {
                     /* list projections */
-                    struct PJ_LIST *lp;
+                    const struct PJ_LIST *lp;
                     int do_long = arg[1] == 'P', c;
                     char *str;
 
-                    for (lp = pj_get_list_ref() ; lp->id ; ++lp) {
+                    for (lp = proj_list_operations() ; lp->id ; ++lp) {
                         if( strcmp(lp->id,"latlong") == 0
                             || strcmp(lp->id,"longlat") == 0
                             || strcmp(lp->id,"geocent") == 0 )
@@ -377,28 +379,28 @@ int main(int argc, char **argv) {
                         }
                     }
                 } else if (arg[1] == '=') { /* list projection 'descr' */
-                    struct PJ_LIST *lp;
+                    const struct PJ_LIST *lp;
 
                     arg += 2;
-                    for (lp = pj_get_list_ref(); lp->id ; ++lp)
+                    for (lp = proj_list_operations(); lp->id ; ++lp)
                         if (!strcmp(lp->id, arg)) {
                             (void)printf("%9s : %s\n", lp->id, *lp->descr);
                             break;
                         }
                 } else if (arg[1] == 'e') { /* list ellipses */
-                    struct PJ_ELLPS *le;
+                    const struct PJ_ELLPS *le;
 
-                    for (le = pj_get_ellps_ref(); le->id ; ++le)
+                    for (le = proj_list_ellps(); le->id ; ++le)
                         (void)printf("%9s %-16s %-16s %s\n",
                                      le->id, le->major, le->ell, le->name);
                 } else if (arg[1] == 'u') { /* list units */
-                    struct PJ_UNITS *lu;
+                    const struct PJ_UNITS *lu;
 
-                    for (lu = pj_get_units_ref(); lu->id ; ++lu)
+                    for (lu = proj_list_units(); lu->id ; ++lu)
                         (void)printf("%12s %-20s %s\n",
                                      lu->id, lu->to_meter, lu->name);
                 } else if (arg[1] == 'd') { /* list datums */
-                    struct PJ_DATUMS *ld;
+                    const struct PJ_DATUMS *ld;
 
                     printf("__datum_id__ __ellipse___ __definition/comments______________________________\n" );
                     for (ld = pj_get_datums_ref(); ld->id ; ++ld)
diff --git a/src/proj_4D_api.c b/src/proj_4D_api.c
index 0fba5097..a0550727 100644
--- a/src/proj_4D_api.c
+++ b/src/proj_4D_api.c
@@ -597,7 +597,7 @@ PJ_INFO proj_info(void) {
 
 ******************************************************************************/
     PJ_INFO info;
-    const char **paths;
+    const char * const *paths;
     char *tmpstr;
     int i, n;
     size_t len = 0;
@@ -847,20 +847,3 @@ PJ_FACTORS proj_factors(PJ *P, LP lp) {
     return factors;
 }
 
-
-const PJ_ELLPS *proj_list_ellps(void) {
-    return pj_get_ellps_ref();
-}
-
-const PJ_UNITS *proj_list_units(void) {
-    return pj_get_units_ref();
-}
-
-const PJ_OPERATIONS *proj_list_operations(void) {
-    return pj_get_list_ref();
-}
-
-const PJ_PRIME_MERIDIANS *proj_list_prime_meridians(void) {
-    return pj_get_prime_meridians_ref();
-}
-
diff --git a/src/proj_internal.h b/src/proj_internal.h
index 6571bce9..13a1cac6 100644
--- a/src/proj_internal.h
+++ b/src/proj_internal.h
@@ -119,7 +119,7 @@ char  *pj_make_args (size_t argc, char **argv);
 /* Lowest level: Minimum support for fileapi */
 void proj_fileapi_set (PJ *P, void *fileapi);
 
-const char **proj_get_searchpath(void);
+const char * const *proj_get_searchpath(void);
 int    proj_get_path_count(void);
 
 size_t pj_strlcpy(char *dst, const char *src, size_t siz);
diff --git a/src/proj_mdist.c b/src/proj_mdist.c
index 244cf199..5f7458b5 100644
--- a/src/proj_mdist.c
+++ b/src/proj_mdist.c
@@ -88,7 +88,7 @@ proj_mdist_ini(double es) {
 }
 	double
 proj_mdist(double phi, double sphi, double cphi, const void *data) {
-	struct MDIST *b = (struct MDIST *)data;
+	const struct MDIST *b = (const struct MDIST *)data;
 	double sc, sum, sphi2, D;
 	int i;
 
@@ -101,7 +101,7 @@ proj_mdist(double phi, double sphi, double cphi, const void *data) {
 }
 	double
 proj_inv_mdist(projCtx ctx, double dist, const void *data) {
-	struct MDIST *b = (struct MDIST *)data;
+	const struct MDIST *b = (const struct MDIST *)data;
 	double s, t, phi, k;
 	int i;
 
diff --git a/src/projects.h b/src/projects.h
index ca2cdbe3..63ea44da 100644
--- a/src/projects.h
+++ b/src/projects.h
@@ -713,8 +713,8 @@ double  pj_qsfn_(double, PJ *);
 double *pj_authset(double);
 double  pj_authlat(double, double *);
 
-COMPLEX pj_zpoly1(COMPLEX, COMPLEX *, int);
-COMPLEX pj_zpolyd1(COMPLEX, COMPLEX *, int, COMPLEX *);
+COMPLEX pj_zpoly1(COMPLEX, const COMPLEX *, int);
+COMPLEX pj_zpolyd1(COMPLEX, const COMPLEX *, int, COMPLEX *);
 
 int pj_deriv(LP, double, const PJ *, struct DERIVS *);
 int pj_factors(LP, const PJ *, double, struct FACTORS *);
diff --git a/src/test228.c b/src/test228.c
index 94f0ec08..57952468 100644
--- a/src/test228.c
+++ b/src/test228.c
@@ -17,8 +17,8 @@ int main(int argc, char* argv[])
 #include <assert.h>
 #include <unistd.h>
 
-volatile int run = 0;
-volatile int started = 0;
+static volatile int run = 0;
+static volatile int started = 0;
 
 static void* thread_main(void* unused)
 {