Re: [boost] [thread] ~mutex and BOOST_VERIFY

Subject: Re: [boost] [thread] ~mutex and BOOST_VERIFY
From: Gaetano Mendola (mendola_at_[hidden])
Date: 2013-05-26 17:41:49

Andrey Semashev <andrey.semashev_at_[hidden]> Wrote in message:
> On Sunday 26 May 2013 22:59:55 Gaetano Mendola wrote:
>> On 26/05/2013 22.39, Andrey Semashev wrote:
>> > On Sunday 26 May 2013 22:28:51 Gaetano Mendola wrote:
>> >> Hi,
>> >> I saw that the destructor of ~mutex doesn't have
>> >> a BOOST_VERIFY anymore on the return value of
>> >> pthread_mutex_destroy. From SVN logs I can see it was
>> >> removed in the commit 75882 to manage the EINTR due
>> >> to some bugged POSIX implementation.
>> >> 
>> >> I will reintroduce the BOOST_VERIFY like this:
>> >>           ~mutex()
>> >>           {
>> >>           
>> >>               int ret;
>> >>               do
>> >>               {
>> >>               
>> >>                   ret = pthread_mutex_destroy(&m);
>> >>               
>> >>               } while (ret == EINTR);
>> >>               BOOST_VERIFY(!ret);
>> >>           
>> >>           }
>> >> 
>> >> while we are at it consider the fact that for the
>> >> same reason ~mutex needs to check for that EINTR
>> >> return value the same should do timed_mutex.
>> > 
>> > Are you sure pthread_mutex_destroy can return EINTR? My Linux man page as
>> > well as [1] explicitly states it can't.
>> > 
>> > [1]
>> > http://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_mutex_ini
>> > t.html
>> Well you know there is no only Linux out there and some of those other
>> POSIX implementation are not 100% POSIX complaint, see ticket #6200,
>> returning EINTR even if the are not supposed to do.
> 
> Then if it's a bug, it should be treated as such - through conditional 
> compilation, so that it doesn't affect valid implementations. Maybe even as a 
> distro-specific patch applied to Boost packages built for it. IMHO, of course.
> 
> Do you have a particular affected platform in mind? Is there a way to detect 
> it in compile time?
> 
> PS: The check for EINTR is missing in other places than ~mutex() and 
> ~timed_mutex(). I found at least ~lightweight_mutex(), ~recursive_mutex(), 
> condition_variable(), condition_variable_any(), ~condition_variable_any(), as 
> well as Boost.Interprocess components: ~posix_recursive_mutex() and 
> ~posix_mutex() to be affected. It seems, you pretty much can't use Boost 
> multithreading on such a buggy platform.
> 

I don't have a such bugged platform, I have just noticed the
 BOOST_VERIFY missing from mutex DTOR and looking at the svn log
 for it I found that the change was made for the ticket #6200. I
 do agree with you that in such platform boost thread can not be
 used as it is know. 

Regards
Gaetano Mendola 

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