[alsa-devel] Event notification

Jaroslav Kysela perex at perex.cz
Thu Dec 20 10:55:14 CET 2007

On Wed, 19 Dec 2007, Miloslaw Smyk wrote:

> Hi,
> My app needs to know about the events occurring to a sound card. 
> Specifically, I am interested in start, stop, pause and volume change. 
> While I could monitor volume by similar means as alsamixer does (is 
> there any doc on this apart from the source code?), I am not sure if 
> monitoring other events is at all possible. I would appreciate any 
> suggestions as to how to do this.

You may write a simple monitor plugin to alsa-lib and create an interface 
to send these events to your code (shm, socket or so). Or you can monitor 
(periodically read) /proc/asound/card/ files (but they won't tell you the 
reason why stream stopped).


Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project

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