Get information about a PCM channel's current capabilities
Synopsis:
#include <sys/asoundlib.h>
int snd_pcm_channel_info(
snd_pcm_t *handle,
snd_pcm_channel_info_t *info );
Arguments:
- handle
- 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().
- info
- A pointer to a
snd_pcm_channel_info_t
structure that snd_pcm_channel_info() fills with information
about the PCM channel.
Before calling this function, set the info structure's
channel member to specify the direction.
This function sets all the other members.
Library:
libasound.so
Use the -l asound option to
qcc
to link against this library.
Description:
The snd_pcm_channel_info() function
fills the info structure with the current capabilities of
the PCM channel selected by handle.
Note:
This function and the plugin-aware version,
snd_pcm_plugin_info(),
get a dynamic
"snapshot" of the system's
current capabilities, which can shrink and grow as subchannels are allocated and freed.
They're similar to
snd_ctl_pcm_channel_info(),
which gets information about the
complete capabilities of the system.
Returns:
EOK on success, a negative errno upon failure. The
errno values are available in the errno.h
file.
Errors:
Additional information for common error values:
- -EINVAL
- The state of handle is
invalid, an invalid params 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 and if you want to recover from the error.
Classification:
QNX Neutrino
| Safety: |
|
| Cancellation point |
No |
| Interrupt handler |
No |
| Signal handler |
Yes |
| Thread |
Read the Caveats |
Caveats:
This function is not thread safe if handle (snd_pcm_t)
is used across multiple threads.