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Macros | Functions
Status Functions
PCM Interface

Macros

#define snd_pcm_status_alloca(ptr)
 allocate an invalid snd_pcm_status_t using standard alloca

Functions

size_t snd_pcm_status_sizeof (void)
 get size of snd_pcm_status_t
int snd_pcm_status_malloc (snd_pcm_status_t **ptr)
 allocate an invalid snd_pcm_status_t using standard malloc
void snd_pcm_status_free (snd_pcm_status_t *obj)
 frees a previously allocated snd_pcm_status_t
void snd_pcm_status_copy (snd_pcm_status_t *dst, const snd_pcm_status_t *src)
 copy one snd_pcm_status_t to another
snd_pcm_state_t snd_pcm_status_get_state (const snd_pcm_status_t *obj)
 Get state from a PCM status container (see snd_pcm_state)
void snd_pcm_status_get_trigger_tstamp (const snd_pcm_status_t *obj, snd_timestamp_t *ptr)
 Get trigger timestamp from a PCM status container.
void snd_pcm_status_get_trigger_htstamp (const snd_pcm_status_t *obj, snd_htimestamp_t *ptr)
 Get trigger hi-res timestamp from a PCM status container.
void snd_pcm_status_get_tstamp (const snd_pcm_status_t *obj, snd_timestamp_t *ptr)
 Get "now" timestamp from a PCM status container.
void snd_pcm_status_get_htstamp (const snd_pcm_status_t *obj, snd_htimestamp_t *ptr)
 Get "now" hi-res timestamp from a PCM status container.
void snd_pcm_status_get_audio_htstamp (const snd_pcm_status_t *obj, snd_htimestamp_t *ptr)
 Get "now" hi-res audio timestamp from a PCM status container.
snd_pcm_sframes_t snd_pcm_status_get_delay (const snd_pcm_status_t *obj)
 Get delay from a PCM status container (see snd_pcm_delay)
snd_pcm_uframes_t snd_pcm_status_get_avail (const snd_pcm_status_t *obj)
 Get number of frames available from a PCM status container (see snd_pcm_avail_update)
snd_pcm_uframes_t snd_pcm_status_get_avail_max (const snd_pcm_status_t *obj)
 Get maximum number of frames available from a PCM status container after last snd_pcm_status call.
snd_pcm_uframes_t snd_pcm_status_get_overrange (const snd_pcm_status_t *obj)
 Get count of ADC overrange detections since last call.

Detailed Description

See the PCM (digital audio) interface page for more details.


Macro Definition Documentation

#define snd_pcm_status_alloca (   ptr)

allocate an invalid snd_pcm_status_t using standard alloca

Parameters:
ptrreturned pointer
Examples:
/test/latency.c.

Function Documentation

void snd_pcm_status_copy ( snd_pcm_status_t dst,
const snd_pcm_status_t src 
)

copy one snd_pcm_status_t to another

Parameters:
dstpointer to destination
srcpointer to source
void snd_pcm_status_free ( snd_pcm_status_t obj)

frees a previously allocated snd_pcm_status_t

Parameters:
objpointer to object to free
void snd_pcm_status_get_audio_htstamp ( const snd_pcm_status_t obj,
snd_htimestamp_t ptr 
)

Get "now" hi-res audio timestamp from a PCM status container.

Parameters:
objpointer to snd_pcm_status_t
ptrPointer to returned timestamp
snd_pcm_uframes_t snd_pcm_status_get_avail ( const snd_pcm_status_t obj)

Get number of frames available from a PCM status container (see snd_pcm_avail_update)

Returns:
Number of frames ready to be read/written
snd_pcm_uframes_t snd_pcm_status_get_avail_max ( const snd_pcm_status_t obj)

Get maximum number of frames available from a PCM status container after last snd_pcm_status call.

Returns:
Maximum number of frames ready to be read/written
snd_pcm_sframes_t snd_pcm_status_get_delay ( const snd_pcm_status_t obj)

Get delay from a PCM status container (see snd_pcm_delay)

Returns:
Delay in frames

Delay is distance between current application frame position and sound frame position. It's positive and less than buffer size in normal situation, negative on playback underrun and greater than buffer size on capture overrun.

void snd_pcm_status_get_htstamp ( const snd_pcm_status_t obj,
snd_htimestamp_t ptr 
)

Get "now" hi-res timestamp from a PCM status container.

Parameters:
objpointer to snd_pcm_status_t
ptrPointer to returned timestamp
snd_pcm_uframes_t snd_pcm_status_get_overrange ( const snd_pcm_status_t obj)

Get count of ADC overrange detections since last call.

Returns:
Count of ADC overrange detections
snd_pcm_state_t snd_pcm_status_get_state ( const snd_pcm_status_t obj)

Get state from a PCM status container (see snd_pcm_state)

Parameters:
objsnd_pcm_status_t pointer
Returns:
PCM state
void snd_pcm_status_get_trigger_htstamp ( const snd_pcm_status_t obj,
snd_htimestamp_t ptr 
)

Get trigger hi-res timestamp from a PCM status container.

Parameters:
objsnd_pcm_status_t pointer
ptrPointer to returned timestamp

Trigger means a PCM state transition (from stopped to running or versa vice). It applies also to pause and suspend. In other words, timestamp contains time when stream started or when it was stopped.

void snd_pcm_status_get_trigger_tstamp ( const snd_pcm_status_t obj,
snd_timestamp_t ptr 
)

Get trigger timestamp from a PCM status container.

Parameters:
objsnd_pcm_status_t pointer
ptrPointer to returned timestamp

Trigger means a PCM state transition (from stopped to running or versa vice). It applies also to pause and suspend. In other words, timestamp contains time when stream started or when it was stopped.

Examples:
/test/latency.c.
void snd_pcm_status_get_tstamp ( const snd_pcm_status_t obj,
snd_timestamp_t ptr 
)

Get "now" timestamp from a PCM status container.

Parameters:
objsnd_pcm_status_t pointer
ptrPointer to returned timestamp
int snd_pcm_status_malloc ( snd_pcm_status_t **  ptr)

allocate an invalid snd_pcm_status_t using standard malloc

Parameters:
ptrreturned pointer
Returns:
0 on success otherwise negative error code
size_t snd_pcm_status_sizeof ( void  )

get size of snd_pcm_status_t

Returns:
size in bytes