From b796301032ee9a18a82441bf25444416b7bc90ad Mon Sep 17 00:00:00 2001
From: miod <>
Date: Sat, 23 Feb 2002 19:50:01 +0000
Subject: [PATCH] Add a caveat section pointing out that people affecting the
 return value of getopt() to char variables instead of int lose on arches
 where char is unsigned by default.

Clean the example by not pasting parts of <unistd.h> into it, and by not
using atoi(3).
---
 src/lib/libc/stdlib/getopt.3 | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/lib/libc/stdlib/getopt.3 b/src/lib/libc/stdlib/getopt.3
index 878290f5..4f6fe974 100644
--- a/src/lib/libc/stdlib/getopt.3
+++ b/src/lib/libc/stdlib/getopt.3
@@ -29,7 +29,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"	$OpenBSD: getopt.3,v 1.14 2000/12/15 14:15:27 aaron Exp $
+.\"	$OpenBSD: getopt.3,v 1.15 2002/02/23 19:50:01 miod Exp $
 .\"
 .Dd April 19, 1994
 .Dt GETOPT 3
@@ -128,8 +128,6 @@ argument),
 returns \-1.
 .Sh EXAMPLES
 .Bd -literal -compact
-extern char *optarg;
-extern int optind;
 int bflag, ch, fd;
 
 bflag = 0;
@@ -194,6 +192,16 @@ The
 .Fn getopt
 function appeared in
 .Bx 4.3 .
+.Sh CAVEATS
+Some software use the very bad practice of affecting the return value of
+.Fn getopt
+to a
+.Ft char
+variable.
+On platforms where
+.Ft char
+is unsigned by default, a comparison of this variable to \-1 to detect the
+end of the argument list will never succeed.
 .Sh BUGS
 The
 .Fn getopt
@@ -247,9 +255,9 @@ while ((c = getopt(argc, argv, "0123456789")) != -1) {
 	case '5': case '6': case '7': case '8': case '9':
 		p = argv[optind - 1];
 		if (p[0] == '-' && p[1] == ch && !p[2])
-			length = atoi(++p);
+			length = ch - '0';
 		else
-			length = atoi(argv[optind] + 1);
+			length = strtol(argv[optind] + 1, NULL, 10);
 		break;
 	}
 }