diff --git a/ChangeLog b/ChangeLog
index 27f90ee2..9ae23d64 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2008-09-06  Nicolas François  <nicolas.francois@centraliens.net>
+
+	* libmisc/obscure.c: Compare characters to '\0', not NULL.
+
 2008-09-06  Nicolas François  <nicolas.francois@centraliens.net>
 
 	* lib/defines.h: Do not include <config.h>. This complicate
diff --git a/libmisc/obscure.c b/libmisc/obscure.c
index 3ab86587..a9b9e0e3 100644
--- a/libmisc/obscure.c
+++ b/libmisc/obscure.c
@@ -109,7 +109,7 @@ static int simple (unused const char *old, const char *new)
 	int size;
 	int i;
 
-	for (i = 0; NULL != new[i]; i++) {
+	for (i = 0; '\0' != new[i]; i++) {
 		if (isdigit (new[i])) {
 			digits = true;
 		} else if (isupper (new[i])) {
@@ -151,7 +151,7 @@ static char *str_lower (char *string)
 {
 	char *cp;
 
-	for (cp = string; NULL != *cp; cp++) {
+	for (cp = string; '\0' != *cp; cp++) {
 		*cp = tolower (*cp);
 	}
 	return string;