Subject: Re: Pthreads ? and Qt4 ? incompatibility in 4.99.36?
To: Vincent <>
From: Andrew Doran <>
List: current-users
Date: 11/19/2007 00:23:03
Hi Vincent,

On Sun, Nov 18, 2007 at 10:12:29PM +0100, Vincent wrote:

> since I have upgraded to 4.99.36 I am experiencing a curious bug (that 
> never happened before) while trying to display a (mere) window under the 
> Qt4 toolkit:
> Error detected by libpthread: Invalid mutex.
> Detected by file "/usr/src/lib/libpthread/pthread_mutex2.c", line 223, 
> function "pthread__mutex_lock_slow".
> See pthread(3) for information.
> QMutex::lock: mutex lock failure: Invalid argument
> I am wondering if this is a (transitory) bug in libpthread (it does not 
> spring up every time, btw), or shall I recompile Qt4 because the API has 
> somehow been modified?

It's most likely to be a bug in Qt4. It's not initializing a mutex using
either pthread_mutex_init() or PTHREAD_MUTEX_INITIALIZER. Another possible
cause is that Qt is corrupting memory (overwriting the mutex with rubbish)
but it is probably just not initialized.