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Re: Saving errno around signal handlers
- From: "Carlos O'Donell" <carlos at redhat dot com>
- To: Roland McGrath <roland at hack dot frob dot com>, Florian Weimer <fweimer at redhat dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>
- Date: Tue, 04 Mar 2014 01:21:50 -0500
- Subject: Re: Saving errno around signal handlers
- Authentication-results: sourceware.org; auth=none
- References: <531077D9 dot 2000308 at redhat dot com> <20140228211938 dot B5FD5744B5 at topped-with-meat dot com> <53143F86 dot 6000201 at redhat dot com> <20140303234207 dot C6ED37444F at topped-with-meat dot com>
On 03/03/2014 06:42 PM, Roland McGrath wrote:
>> On 02/28/2014 10:19 PM, Roland McGrath wrote:
>>>> POSIX has green-lighted saving errno around signal handlers.
>>>
>>> I don't even know what you might think that means. Whenever talking about
>>> a change in a standard, provide a reference to the actual change in the
>>> actual standard.
>>
>> It's about this change:
>>
>> <http://austingroupbugs.net/view.php?id=807>
>
> So the standard is not going to be changed to require that signal handling
> save and restore errno implicitly. (It would have been a highly suspect
> change.) It's being clarified to say that the implementation is free to do
> so. But applications cannot assume any such thing, so any such future
> application remains as broken as such applications are today. I see no
> rationale even slightly compelling for making libc do this magic. In fact,
> it would clearly do harm to people developing applications on glibc-based
> systems but intending to write POSIX-conformant code.
In that it would mask potential errors in the signal handling code?
Cheers,
Carlos.