1 files changed, 3 insertions, 1 deletions
diff --git a/src/PJ_misrsom.c b/src/PJ_misrsom.c
index b9b97117..0308fc42 100644
--- a/src/PJ_misrsom.c
+++ b/src/PJ_misrsom.c
@@ -21,7 +21,10 @@
  *****************************************************************************/
 /* based upon Snyder and Linck, USGS-NMD */
 #define PJ_LIB__
+
 #include <errno.h>
+#include <math.h>
+
 #include "proj.h"
 #include "projects.h"
 
@@ -212,4 +215,3 @@ PJ *PROJECTION(misrsom) {
 
    return P;
 }
-