[alsa-devel] Should snd_pcm_drop() interrupt snd_pcm_writei() call?

Takashi Iwai tiwai at suse.de
Fri May 15 17:30:20 CEST 2009


At Fri, 15 May 2009 16:28:06 +0200 (CEST),
Marek Peca wrote:
> 
> >> This explains the problems I encountered. I missed the information, that
> >> these functions are not meant to be thread-safe.
> >
> > Although it's not recommended, the behavior you described sounds strange.
> > Could you check whether this still happens with the very latest
> > alsa-lib version?
> 
> Yes, we will try to, but I need some cooperation with colleague, so it 
> will take some time.
> 
> > Also I guess this depends on the plugin to be used, e.g. dmix or not.
> 
> I see. Please, can you tell me, whether I should rewrite my program to 
> purely single-thread acces to snd_pcm_write & snd_pcm_drop, or should I 
> expect, that in ALSA (with proper plugin) it should work in correct 
> releases?

A safer option is the single thread access if you want your app to
support many different systems including old ALSA.  In addition, you
could add a different approach depending on the version, e.g. by
checking in configure script.

Anyway, checking with the latest version is helpful for us ;)


thanks,

Takashi


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