diff --git a/libc/string/index.c b/libc/string/index.c
index fb0492f..81bfba4 100644
--- a/libc/string/index.c
+++ b/libc/string/index.c
@@ -34,7 +34,7 @@
 index(const char *p, int ch)
 {
 	for (;; ++p) {
-		if (*p == ch)
+		if (*p == (char) ch)
 			return((char *)p);
 		if (!*p)
 			return((char *)NULL);