Qt 4.4 QtConcurrent and libthread_xu

Simon 'corecode' Schubert corecode at fs.ei.tum.de
Wed May 7 15:05:43 PDT 2008

Aggelos Economopoulos wrote:
    In libthread_xu it assumes non-NULL and will crash.

    Try this patch.  It will do the same check that libc_r does.  I'm
    not convinced that Qt isn't broken, though, Qt shouldn't be passing
    NULL to the mutex functions, it should be passing the address of
    a pthread_mutex_t which itself can be NULL, but it should be passing
Still, it's bad form for a library function to crash just because somebody
called it with an obviously invalid argument.
Not sure about that. There are many illeagal pointers that can't be catched
so why treat NULL differently?
Because NULL is guaranteed not to point to an object.
This is true.  Fair enough, we can add a check.  I still wonder why they 
are passing NULL in the first place.

And a crash with an obvious stack trace shows that there is a problem that
should be fixed.
While an error of EINVAL is hard to debug?
Yes, most people seem to ignore error messages returned by mutex functions 
anyways, or so I've heard :)

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