diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 2262794..bf04185 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -1813,7 +1813,7 @@
     if (fp_out == NULL)
     {
 	EMSG2(_("E138: Can't write viminfo file %s!"),
-		       (fp_in == NULL || tempname == NUL) ? fname : tempname);
+		       (fp_in == NULL || tempname == NULL) ? fname : tempname);
 	if (fp_in != NULL)
 	    fclose(fp_in);
 	goto end;