[vlc-devel] [PATCH] In SigThread, handle sigwait() failures gracefully.

Rémi Denis-Courmont remi at remlab.net
Sat Jul 11 11:46:06 CEST 2009

Le vendredi 10 juillet 2009 23:50:33 Fabian Keil, vous avez écrit :
> The problem seems to be caused by vlc expecting a reasonable
> signal value in signum, even if sigwait() failed. The attached
> patch fixes the problem for me.

The only specified failure for sigwait() is an invalid input signal set. I 
think this is not possible in that particular case. If it is then a bug in the 
code above sigwait() needs to be fixed, not the sigwait() code.

I am not sure if there is anything to do about unspecified errors. For all I 
know, trying to work around them could cause a busy loop which is arguably 
worse than crashing or at least exiting the signal interface.

Maybe Qt4 is installing signal handlers in some version. If I'm not mistaken, 
the behavior of sigwait() is unspecified if sigaction() is invoked on the same 

Rémi Denis-Courmont

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