1 files changed, 1 insertions, 1 deletions

diff --git a/parse.c b/parse.c
index 8304ded837ba..753a50def1fb 100644
--- a/parse.c
+++ b/parse.c
@@ -259,7 +259,7 @@ int isarg(const char *s)		/* is s in argument list for current function? */
 	Node *p = arglist;
 	int n;
 
-	for (n = 0; p != 0; p = p->nnext, n++)
+	for (n = 0; p != NULL; p = p->nnext, n++)
 		if (strcmp(((Cell *)(p->narg[0]))->nval, s) == 0)
 			return n;
 	return -1;