Re: [alsa-devel] [PATCH] alsa-lib: snd_pcm_delay and friends do not account for a write being currently in progress

John Lindgren wrote:

On Thu, 2010-06-03 at 08:40 +0200, Clemens Ladisch wrote:

...

Alsa-lib is not thread safe.

From http://alsa-project.org/main/index.php/Main_Page:

    ALSA has the following significant features:
    ...
    SMP and thread-safe design.

So, that's a big lie?

That applies to the kernel code.

Most functions in alsa-lib must not be called at the same time on the same device handle. (Don't ask me where this is documented.)

...

... poll()

Would it work to simply call snd_pcm_wait?

Yes. (I usually suggest poll because the code that writes audio data often wants to be informed of some other event. If your writing loop doesn't need to be interrupted, snd_pcm_wait works just fine.)

Regards, Clemens