Saving errno around signal handlers

[Carlos O'Donell]

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.