diff --git a/WINGs/WINGs/WUtil.h b/WINGs/WINGs/WUtil.h
index dbf7074a..347e70ee 100644
--- a/WINGs/WINGs/WUtil.h
+++ b/WINGs/WINGs/WUtil.h
@@ -245,7 +245,7 @@ void wfree(void *ptr);
 void wrelease(void *ptr);
 void* wretain(void *ptr);
 
-char* wstrdup(char *str);
+char *wstrdup(const char *str);
 char* wstrndup(char *str, size_t len);
 
 /* Concatenate str1 with str2 and return that in a newly malloc'ed string.
diff --git a/WINGs/string.c b/WINGs/string.c
index 70277c8a..956ad3a5 100644
--- a/WINGs/string.c
+++ b/WINGs/string.c
@@ -163,7 +163,7 @@ char *wtrimspace(char *s)
 	return c;
 }
 
-char *wstrdup(char *str)
+char *wstrdup(const char *str)
 {
 	assert(str != NULL);