snd_pcm_channel

Synopsis:

#include <sys/asoundlib.h>

int snd_pcm_channel_resume ( snd_pcm_t *pcm,
                             int channel );

pcm: The handle for the PCM device, which you must have opened by calling snd_pcm_open_name(), snd_pcm_open(), or snd_pcm_open_preferred().
channel: The channel; SND_PCM_CHANNEL_CAPTURE or SND_PCM_CHANNEL_PLAYBACK.

libasound.so

Use the -l asound option with qcc to link against this library.

The snd_pcm_channel_resume() function resumes a channel by calling snd_pcm_capture_resume() or snd_pcm_playback_resume(), depending on the value of channel.

If the channel is in the SUSPENDED (SND_PCM_STATUS_SUSPENDED), one of the following occurs when you call this function:

If the channel is hard suspended, calling this function clears any underlying paused condition (e.g., snd_pcm_channel_pause() was called before moving to the SND_PCM_STATUS_SUSPENDED state). However, because you are in the SND_PCM_STATUS_SUSPENDED state and waiting for higher priority audio stream to complete, the channel remains in the SUSPENDED state.
If the channel is in the soft suspended state, calling this function clears any underlying paused condition (e.g., snd_pcm_channel_pause() was called before moving to SND_PCM_STATUS_SUSPENDED state) and the channel plays immediately and transitions to the SND_PCM_STATUS_RUNNING state.
If both the hard suspended and soft suspended conditions occur, the hard suspended state takes precedence. In other words, calling the function clears any pending paused conditione.g., snd_pcm_channel_pause()) but the channel remains in the SND_PCM_STATUS_SUSPENDED state.

For more information, see the Audio Concurrency Management chapter in this guide.

EOK on success, a negative errno upon failure. The errno values are available in the errno.h file.

Additional information for common error values:

-EINVAL: The state of handle is invalid, an invalid channel was provided as input, or an invalid state change occurred. You can call snd_pcm_channel_status() to check if the state change was invalid.
-EIO: The channel isn't valid that was passed in was not set to SND_PCM_CHANNEL_PLAYBACK or SND_PCM_CHANNEL_CAPTURE.
-ENOTSUP: Resume isn't supported on the PCM device that's referenced by the PCM handle (pcm).

QNX Neutrino

This function is not thread safe if pcm (snd_pcm_t) is used across multiple threads.