From: Florian Weimer <fweimer@redhat.com>
To: Alejandro Colomar via Libc-alpha <libc-alpha@sourceware.org>
Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>,
Alejandro Colomar <colomar.6.4.3@gmail.com>,
linux-man@vger.kernel.org
Subject: Re: Bug or misdocumented feature in pthread_setaffinity_np.3
Date: Mon, 07 Sep 2020 11:24:49 +0200 [thread overview]
Message-ID: <87sgbu7xcu.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <486f9d85-2828-2b60-990c-3499b2a89559@gmail.com> (Alejandro Colomar via Libc-alpha's message of "Mon, 7 Sep 2020 11:00:05 +0200")
* Alejandro Colomar via Libc-alpha:
> pthread_setaffinity_np() and pthread_getaffinity_np(), "on error,
> return a non-zero error number". Usually that kind of library
> functions return -1, and I don't know if this case is different. The
> RETURN VALUE section doesn't specify. Actually the words "error
> number" hint that it is an `errno` value, because it's the same words
> in errno.3, but it could be clearer, and maybe also point to errno(3)
> in that page.
Most libpthread functions return errno codes instead of in addition to
setting errno. This is something that POSIX requires. The asymmetry is
annoying. I think it dates back to the days where libpthread was purely
a library in some implementations, to be used with a C library that was
not even aware of threads and did not have a per-thread errno variable.
(Of course, that didn't work too well, but people tried.)
Thanks,
Florian
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next prev parent reply other threads:[~2020-09-07 9:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-07 9:00 Alejandro Colomar
2020-09-07 9:21 ` Samuel Thibault
2020-09-07 9:21 ` Michael Kerrisk (man-pages)
2020-09-07 9:26 ` Alejandro Colomar
2020-09-07 9:24 ` Florian Weimer [this message]
2020-09-07 9:31 ` Michael Kerrisk (man-pages)
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