snd_ctl_file_descriptor()
Get the control file descriptor
Synopsis:
#include <sys/asoundlib.h>
int snd_ctl_file_descriptor( snd_ctl_t *handle );
Arguments:
- handle
- The handle for the control connection to the card. This must be a handle created by snd_ctl_open().
Library:
libasound.so
Use the -l asound option with qcc to link against this library.
Description:
The snd_ctl_file_descriptor() function returns the file descriptor of the connection to the control interface.
You can use the file descriptor for the select() function (see the QNX Neutrino C Library Reference) for determining if something can be read or written. Your application should then call snd_ctl_read() if data is waiting to be read.
Returns:
The file descriptor of the connection to the control interface, or a negative value if an error occurs.
Errors:
- -EINVAL
- Invalid handle argument.
Classification:
QNX Neutrino
| Safety: | |
|---|---|
| Cancellation point | No |
| Interrupt handler | No |
| Signal handler | Yes |
| Thread | Yes |
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