From: Alejandro Colomar <alx.manpages@gmail.com>
To: mtk.manpages@gmail.com, linux-man@vger.kernel.org
Cc: Alejandro Colomar <alx.manpages@gmail.com>,
libc-alpha@sourceware.org, Paul Eggert <eggert@cs.ucla.edu>
Subject: [PATCH v3 2/2] timegm.3: Remove recommendation against their use
Date: Mon, 11 Oct 2021 13:54:08 +0200 [thread overview]
Message-ID: <20211011115406.11430-2-alx.manpages@gmail.com> (raw)
In-Reply-To: <a8e09a03-3eb2-d6c0-c662-e3db800fe2fc@gmail.com>
It was straight after a note that they are nonstandard functions,
which already tells the user that if portability is in mind, they
shouldn't be used, so this recommendation adds nothing in that
sense.
Also, there's a note that timelocal() should _never_ be used, due
to mktime() being identical and in the POSIX standard (it is also
in C99), so this note would also add nothing in that sense.
So the only uses not covered by those other notes are non-portable
uses of timegm(3). In that scenario, it is an excellent function.
When porting to other systems, it is trivial to port timegm(3)
using only standard C (I didn't test it; use on your own):
// timegm.c
#include <time.h>
time_t timegm(struct tm *tm)
{
tm->tm_isdst = 0;
return mktime(tm) - timezone;
}
Cc: Paul Eggert <eggert@cs.ucla.edu>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
---
man3/timegm.3 | 1 -
1 file changed, 1 deletion(-)
diff --git a/man3/timegm.3 b/man3/timegm.3
index b848e83e1..0e8528b26 100644
--- a/man3/timegm.3
+++ b/man3/timegm.3
@@ -97,7 +97,6 @@ T} Thread safety MT-Safe env locale
.SH CONFORMING TO
These functions are nonstandard GNU extensions
that are also present on the BSDs.
-Avoid their use.
.SH NOTES
The
.BR timelocal ()
--
2.33.0
next prev parent reply other threads:[~2021-10-11 11:57 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-10 10:52 [PATCH] ctime.3: mktime() may modify tm_hour due to tm_isdst Alejandro Colomar
2021-10-11 10:27 ` Alejandro Colomar (man-pages)
2021-10-11 11:12 ` [PATCH v2 1/2] " Alejandro Colomar
2021-10-11 15:36 ` Paul Eggert
2021-10-15 21:49 ` Alejandro Colomar (man-pages)
2021-10-11 11:12 ` [PATCH v2 2/2] timegm.3: Remove recommendation against use of timegm() Alejandro Colomar
2021-10-11 15:40 ` Paul Eggert
2021-10-15 22:03 ` Alejandro Colomar (man-pages)
2021-10-16 0:20 ` Paul Eggert
2021-10-17 18:02 ` Alejandro Colomar (man-pages)
2021-10-17 22:00 ` Paul Eggert
2021-11-05 0:47 ` Alejandro Colomar (man-pages)
2021-11-08 8:05 ` Paul Eggert
2021-10-11 11:54 ` [PATCH v3 1/2] ctime.3: mktime() may modify tm_hour due to tm_isdst Alejandro Colomar
2021-10-11 11:54 ` Alejandro Colomar [this message]
2021-10-11 15:37 ` [PATCH] " Paul Eggert
2021-10-11 22:05 ` Joseph Myers
2021-10-15 21:55 ` Alejandro Colomar (man-pages)
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