diff --git a/pmap.c b/pmap.c
index 042d9dc0..38b3629f 100644
--- a/pmap.c
+++ b/pmap.c
@@ -909,10 +909,13 @@ static int config_read (char *rc_filename)
 }
 
 
-static int config_create (char *rc_filename)
+static int config_create (const char *rc_filename)
 {
 	FILE *f;
 
+	if (rc_filename == NULL)
+		return 0;
+
 	/* check if rc exists */
 	f = fopen(rc_filename, "r");