fix UB with the function iscntrl()

From commit 6818e07291 by NRK, thanks
3 years ago · e73651f12a
parent 31fa07b984
commit e73651f12a
1 changed files with 1 additions and 1 deletions
--- a/dmenu.c
+++ b/dmenu.c
@ -415,7 +415,7 @@ keypress(XKeyEvent *ev)
 	switch(ksym) {
 	default:
 insert:
-		if (!iscntrl(*buf))
+		if (!iscntrl((unsigned char)*buf))
 			insert(buf, len);
 		break;
 	case XK_Delete: