Re: mutexes try_lock noexcept issue

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From	Alexander Terekhov<terekhov@web.de>
Newsgroups	comp.std.c++
Subject	Re: mutexes try_lock noexcept issue
Date	Wed, 11 Jan 2012 09:58:58 -0800 (PST)
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Pete Becker wrote:
>
>  On 2012-01-01 22:26:47 +0000, viboes said:
>
>  >   In 30.4.1.2.2        Class recursive_mutex   [thread.mutex.recursive]
>  >
>  >   try_lock is declared as noexcept
>  >
>  >      bool try_lock() noexcept;
>  >
>  >   but 30.4.1.2.1       Class mutex declare it without noexcept
>  >      bool try_lock();
>  >
>  >   The same applies for timed_mutex and recursive_timed_mutex.
>  >
>  >   Shouldn't both be coherent. When could try_lock throw an exception?
>  >
>
>  If the mutex is already owned by the calling thread, the behavior of a
>  call to try_lock() is undefined. One possibility is to throw an
>  exception. For a recursive mutex, the behavior is well defined.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutex_lock.html

"ERRORS

The pthread_mutex_lock() and pthread_mutex_trylock() functions shall
fail if:

[EAGAIN]

The mutex could not be acquired because the maximum number of recursive
locks for mutex has been exceeded."

How is that error is supposed to be reported with bool try_lock()
noexcept given that false bool reflects

"The pthread_mutex_trylock() function shall fail if:

[EBUSY]

The mutex could not be acquired because it was already locked. "

<?>

regards,
alexander.



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Thread

mutexes try_lock noexcept issue viboes<vicente.botet@wanadoo.fr> - 2012-01-01 14:26 -0800
  Re: mutexes try_lock noexcept issue Pete Becker<pete@versatilecoding.com> - 2012-01-03 13:01 -0800
    Re: mutexes try_lock noexcept issue Alexander Terekhov<terekhov@web.de> - 2012-01-11 09:58 -0800
      Re: mutexes try_lock noexcept issue Daniel Krügler<daniel.kruegler@googlemail.com> - 2012-01-14 17:16 -0800

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