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added some documentation

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Taylor Holberton
2016-11-23 13:18:24 -08:00
parent 1aad83d6ac
commit 17a102424c
1 changed files with 29 additions and 0 deletions
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src/pcm.c
+29
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@@ -172,6 +172,7 @@ struct pcm {
int underruns;
/** Size of the buffer */
unsigned int buffer_size;
/** The boundary for ring buffer pointers */
unsigned int boundary;
/** Description of the last error that occured */
char error[PCM_ERROR_MAX];
@@ -182,7 +183,9 @@ struct pcm {
struct snd_pcm_sync_ptr *sync_ptr;
void *mmap_buffer;
unsigned int noirq_frames_per_msec;
/** The delay of the PCM, in terms of frames */
long pcm_delay;
/** The subdevice corresponding to the PCM */
unsigned int subdevice;
};
@@ -709,6 +712,12 @@ struct pcm_mask *pcm_params_get_mask(struct pcm_params *pcm_params,
return (struct pcm_mask *)param_to_mask(params, p);
}
/** Get the minimum of a specified PCM parameter.
* @param pcm_params A PCM parameters structure.
* @param param The specified parameter to get the minimum of.
* @returns On success, the parameter minimum.
* On failure, zero.
*/
unsigned int pcm_params_get_min(struct pcm_params *pcm_params,
enum pcm_param param)
{
@@ -725,6 +734,12 @@ unsigned int pcm_params_get_min(struct pcm_params *pcm_params,
return param_get_min(params, p);
}
/** Get the maximum of a specified PCM parameter.
* @param pcm_params A PCM parameters structure.
* @param param The specified parameter to get the maximum of.
* @returns On success, the parameter maximum.
* On failure, zero.
*/
unsigned int pcm_params_get_max(struct pcm_params *pcm_params,
enum pcm_param param)
{
@@ -1118,6 +1133,14 @@ int pcm_state(struct pcm *pcm)
return pcm->mmap_status->state;
}
/** Waits for frames to be available for read or write operations.
* @param pcm A PCM handle.
* @param timeout The maximum amount of time to wait for, in terms of milliseconds.
* @returns If frames became available, one is returned.
* If a timeout occured, zero is returned.
* If an error occured, a negative number is returned.
* @ingroup libtinyalsa-pcm
*/
int pcm_wait(struct pcm *pcm, int timeout)
{
struct pollfd pfd;
@@ -1253,6 +1276,12 @@ int pcm_mmap_read(struct pcm *pcm, void *data, unsigned int count)
return pcm_mmap_transfer(pcm, data, count);
}
/** Gets the delay of the PCM, in terms of frames.
* @param pcm A PCM handle.
* @returns On success, the delay of the PCM.
* On failure, a negative number.
* @ingroup libtinyalsa-pcm
*/
long pcm_get_delay(struct pcm *pcm)
{
if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_DELAY, &pcm->pcm_delay) < 0)