Of course, fcntl errno case returns -1, which must be converted to 0

with guenther

diff --git a/lib/libc/gen/isatty.c b/lib/libc/gen/isatty.c
index 3b63f25..c0b5436 100644 (file)
--- a/lib/libc/gen/isatty.c
+++ b/lib/libc/gen/isatty.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: isatty.c,v 1.9 2015/05/17 01:22:01 deraadt Exp $ */
+/*     $OpenBSD: isatty.c,v 1.10 2015/05/17 01:56:02 deraadt Exp $ */
 /*
  * Copyright (c) 1988, 1993
  *     The Regents of the University of California.  All rights reserved.
@@ -33,5 +33,5 @@
 int
 isatty(int fd)
 {
-       return (fcntl(fd, F_ISATTY));
+       return fcntl(fd, F_ISATTY) != -1;
 }