From 88aa612a4e75833368f6c4552d95d1d5c1232555 Mon Sep 17 00:00:00 2001
From: Jakob Kaivo <jkk@ung.org>
Date: Tue, 14 Nov 2023 16:29:08 -0500
Subject: return 0 if c is EOF

---
 src/ctype/isupper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/ctype/isupper.c b/src/ctype/isupper.c
index ccc7ff23..b188dc28 100644
--- a/src/ctype/isupper.c
+++ b/src/ctype/isupper.c
@@ -10,7 +10,7 @@ int isupper(int c)
 
 	ASSERT_REPRESENTABLE(c, 0, UCHAR_MAX, unsigned char, EOF);
 
-	return map[c] & CT_UPPER;
+	return c == EOF ? 0 : map[c] & CT_UPPER;
 }
 
 /***
-- 
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