1 files changed, 2 insertions, 2 deletions
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;