From: Austin Clements <amdragon@MIT.EDU>
To: David Edmondson <dme@dme.org>
Cc: notmuch@notmuchmail.org
Subject: Re: [RFC][PATCH] notmuch: Workaround to allow ignoring non-void function return.
Date: Thu, 22 Dec 2011 14:03:05 -0500 [thread overview]
Message-ID: <20111222190305.GA324@mit.edu> (raw)
In-Reply-To: <cunfwgdvzpy.fsf@hotblack-desiato.hh.sledj.net>
Quoth David Edmondson on Dec 22 at 7:21 am:
> On Thu, 22 Dec 2011 02:03:45 -0500, Austin Clements <amdragon@MIT.EDU> wrote:
> > I must admit I haven't been following the warnings problem very
> > closely, but perhaps we shouldn't be ignoring these return codes?
>
> In general I agree, but what would we do if writing an error message to
> stderr fails?
This was discussed on IRC, but calls to write(2) should never be bare.
I believe it's marked warn_unused_result not because libc is so
concerned with people checking for error returns (otherwise all sorts
of things would be marked warn_unused_result) but because even a
successful write can be a short write. Hence, not checking the result
is a bug, even if you don't care about errors.
fwrite's a little trickier, since it will only short-write on an
error, so to me it seems perfectly legitimate to ignore the result if
you don't care about errors.
I don't seem to have whatever glibc version the buildbot does that
marks these warn_unused_result, but I can reproduce it by adding
__attribute__((warn_unused_result))
ssize_t write(int fd, const void *buf, size_t count);
__attribute__((warn_unused_result))
size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream);
to notmuch-client.h. Testing with these, if I add any form of result
checking, even if it does nothing in most cases, GCC is quiet.
next prev parent reply other threads:[~2011-12-22 19:02 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-21 21:38 [RFC][PATCH] notmuch: Workaround to allow ignoring non-void function return David Edmondson
2011-12-22 7:03 ` Austin Clements
2011-12-22 7:21 ` David Edmondson
2011-12-22 19:03 ` Austin Clements [this message]
2011-12-22 19:25 ` David Edmondson
2011-12-22 20:04 ` David Edmondson
2011-12-22 20:15 ` Austin Clements
2011-12-22 20:15 ` [PATCH] Properly handle short writes in sigint handlers Austin Clements
2011-12-23 8:10 ` David Edmondson
2011-12-23 12:30 ` Tomi Ollila
2011-12-25 0:38 ` Austin Clements
2011-12-25 0:38 ` Austin Clements
2011-12-23 19:10 ` Dmitry Kurochkin
2012-01-10 11:13 ` David Bremner
2012-01-11 13:04 ` Tomi Ollila
2011-12-22 9:32 ` [RFC][PATCH] notmuch: Workaround to allow ignoring non-void function return Dmitry Kurochkin
2011-12-22 11:24 ` David Edmondson
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