diff --git a/demo/demo.c b/demo/demo.c
index d69426f..c1fcfcd 100644
--- a/demo/demo.c
+++ b/demo/demo.c
@@ -32,7 +32,7 @@
 
 #include "tommath.h"
 
-static void ndraw(mp_int *a, char *name)
+static void ndraw(mp_int *a, const char *name)
 {
    char buf[16000];
 
diff --git a/demo/timing.c b/demo/timing.c
index 38561d4..9e7d03b 100644
--- a/demo/timing.c
+++ b/demo/timing.c
@@ -17,7 +17,7 @@
 #endif
 
 
-static void ndraw(mp_int *a, char *name)
+static void ndraw(mp_int *a, const char *name)
 {
    char buf[4096];