From addd5e9749481d2e50ab948537244bcaad7db403 Mon Sep 17 00:00:00 2001
From: bakkeby <bakkeby@gmail.com>
Date: Mon, 28 Mar 2022 11:21:42 +0200
Subject: [PATCH] avoid potential UB when using isprint()

all the ctype.h functions' argument must be representable as an unsigned
char or as EOF, otherwise the behavior is undefined.

ref. https://git.suckless.org/st/commit/af3bb68add1c40d19d0dee382009e21b0870a38f.html
---
 st.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/st.c b/st.c
index 481cf10..8095996 100644
--- a/st.c
+++ b/st.c
@@ -397,7 +397,7 @@ static const char base64_digits[] = {
 char
 base64dec_getc(const char **src)
 {
-	while (**src && !isprint(**src))
+	while (**src && !isprint((unsigned char)**src))
 		(*src)++;
 	return **src ? *((*src)++) : '=';  /* emulate padding if string ends */
 }