[Xcb] More pthread stubs.

Rémi Denis-Courmont remi at remlab.net
Wed Mar 10 11:27:04 PST 2010

Le mercredi 10 mars 2010 21:11:56 M Joonas Pihlaja, vous avez écrit :
> Personally I'm not a huge fan of providing checking since we'd need to
> actually save some state somewhere, and also we'd need to make some
> assumptions about the system's static mutex initializers.  While
> pthreads itself only supports PTHREAD_MUTEX_INITIALIZER, apps use
> non-portable initializers like PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP.
> I suppose we could autoconf our way out of this though. *sigh*

Error-checking means error-checking though. If an application selects to use 
an error-checking mutex, it probably relies on the error semantics. Even if it 
is for pure debugging purpose, it is not safe to return zero. I have myself 
written such "horrors" as
#define foo_assert_locked(lock) assert(pthread_mutex_lock(lock) == EDEADLK);
which are perfectly valid code. Your patch would break that code.

It could even be for more serious functionality, e.g. detecting transactional 
deadlocks. Otherwise, the application might as well use a fast mutex.

Rémi Denis-Courmont

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