diff --git a/src/ex_getln.c b/src/ex_getln.c
index ef7ca91..9d0695a 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -4445,7 +4445,7 @@
     else
     {
 	n = string_to_key(p_cedit, FALSE);
-	if (vim_isprintc(n))
+	if (n == 0 || vim_isprintc(n))
 	    return e_invalid_argument;
 	cedit_key = n;
     }