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Hardware Parameters
[PCM Interface]


Defines

#define snd_pcm_hw_params_alloca(ptr)
 allocate an invalid snd_pcm_hw_params_t using standard alloca

Functions

int snd_pcm_hw_params_any (snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
 Fill params with a full configuration space for a PCM.
int snd_pcm_hw_params_can_mmap_sample_resolution (const snd_pcm_hw_params_t *params)
 Check, if hardware supports sample-resolution mmap for given configuration.
int snd_pcm_hw_params_is_double (const snd_pcm_hw_params_t *params)
 Check, if hardware does double buffering for start/stop for given configuration.
int snd_pcm_hw_params_is_batch (const snd_pcm_hw_params_t *params)
 Check, if hardware does double buffering for data transfers for given configuration.
int snd_pcm_hw_params_is_block_transfer (const snd_pcm_hw_params_t *params)
 Check, if hardware does block transfers for samples for given configuration.
int snd_pcm_hw_params_can_overrange (const snd_pcm_hw_params_t *params)
 Check, if hardware supports overrange detection.
int snd_pcm_hw_params_can_pause (const snd_pcm_hw_params_t *params)
 Check, if hardware supports pause.
int snd_pcm_hw_params_can_resume (const snd_pcm_hw_params_t *params)
 Check, if hardware supports resume.
int snd_pcm_hw_params_is_half_duplex (const snd_pcm_hw_params_t *params)
 Check, if hardware does half-duplex only.
int snd_pcm_hw_params_is_joint_duplex (const snd_pcm_hw_params_t *params)
 Check, if hardware does joint-duplex (playback and capture are somewhat correlated).
int snd_pcm_hw_params_can_sync_start (const snd_pcm_hw_params_t *params)
 Check, if hardware supports synchronized start with sample resolution.
int snd_pcm_hw_params_get_rate_numden (const snd_pcm_hw_params_t *params, unsigned int *rate_num, unsigned int *rate_den)
 Get rate exact info from a configuration space.
int snd_pcm_hw_params_get_sbits (const snd_pcm_hw_params_t *params)
 Get sample resolution info from a configuration space.
int snd_pcm_hw_params_get_fifo_size (const snd_pcm_hw_params_t *params)
 Get hard are FIFO size info from a configuration space.
size_t snd_pcm_hw_params_sizeof (void)
 get size of snd_pcm_hw_params_t
int snd_pcm_hw_params_malloc (snd_pcm_hw_params_t **ptr)
 allocate an invalid snd_pcm_hw_params_t using standard malloc
void snd_pcm_hw_params_free (snd_pcm_hw_params_t *obj)
 frees a previously allocated snd_pcm_hw_params_t
void snd_pcm_hw_params_copy (snd_pcm_hw_params_t *dst, const snd_pcm_hw_params_t *src)
 copy one snd_pcm_hw_params_t to another
int snd_pcm_hw_params_get_access (const snd_pcm_hw_params_t *params, snd_pcm_access_t *_access)
int snd_pcm_hw_params_test_access (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_access_t _access)
int snd_pcm_hw_params_set_access (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_access_t _access)
int snd_pcm_hw_params_set_access_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_access_t *_access)
int snd_pcm_hw_params_set_access_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_access_t *_access)
int snd_pcm_hw_params_set_access_mask (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_access_mask_t *mask)
int snd_pcm_hw_params_get_access_mask (snd_pcm_hw_params_t *params, snd_pcm_access_mask_t *mask)
int snd_pcm_hw_params_get_format (const snd_pcm_hw_params_t *params, snd_pcm_format_t *val)
int snd_pcm_hw_params_test_format (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_format_t val)
int snd_pcm_hw_params_set_format (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_format_t val)
int snd_pcm_hw_params_set_format_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_format_t *format)
int snd_pcm_hw_params_set_format_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_format_t *format)
int snd_pcm_hw_params_set_format_mask (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_format_mask_t *mask)
void snd_pcm_hw_params_get_format_mask (snd_pcm_hw_params_t *params, snd_pcm_format_mask_t *mask)
int snd_pcm_hw_params_get_subformat (const snd_pcm_hw_params_t *params, snd_pcm_subformat_t *subformat)
int snd_pcm_hw_params_test_subformat (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_subformat_t subformat)
int snd_pcm_hw_params_set_subformat (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_subformat_t subformat)
int snd_pcm_hw_params_set_subformat_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_subformat_t *subformat)
int snd_pcm_hw_params_set_subformat_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_subformat_t *subformat)
int snd_pcm_hw_params_set_subformat_mask (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_subformat_mask_t *mask)
void snd_pcm_hw_params_get_subformat_mask (snd_pcm_hw_params_t *params, snd_pcm_subformat_mask_t *mask)
int snd_pcm_hw_params_get_channels (const snd_pcm_hw_params_t *params, unsigned int *val)
int snd_pcm_hw_params_get_channels_min (const snd_pcm_hw_params_t *params, unsigned int *val)
int snd_pcm_hw_params_get_channels_max (const snd_pcm_hw_params_t *params, unsigned int *val)
int snd_pcm_hw_params_test_channels (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val)
int snd_pcm_hw_params_set_channels (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val)
int snd_pcm_hw_params_set_channels_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
int snd_pcm_hw_params_set_channels_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
int snd_pcm_hw_params_set_channels_minmax (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *min, unsigned int *max)
int snd_pcm_hw_params_set_channels_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
int snd_pcm_hw_params_set_channels_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
int snd_pcm_hw_params_set_channels_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
int snd_pcm_hw_params_get_rate (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_rate_min (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_rate_max (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_test_rate (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
int snd_pcm_hw_params_set_rate (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
int snd_pcm_hw_params_set_rate_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_rate_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_rate_minmax (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *min, int *mindir, unsigned int *max, int *maxdir)
int snd_pcm_hw_params_set_rate_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_rate_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_rate_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_rate_resample (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val)
int snd_pcm_hw_params_get_rate_resample (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
int snd_pcm_hw_params_set_export_buffer (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val)
int snd_pcm_hw_params_get_export_buffer (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
int snd_pcm_hw_params_get_period_time (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_period_time_min (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_period_time_max (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_test_period_time (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
int snd_pcm_hw_params_set_period_time (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
int snd_pcm_hw_params_set_period_time_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_period_time_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_period_time_minmax (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *min, int *mindir, unsigned int *max, int *maxdir)
int snd_pcm_hw_params_set_period_time_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_period_time_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_period_time_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_period_size (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *frames, int *dir)
int snd_pcm_hw_params_get_period_size_min (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *frames, int *dir)
int snd_pcm_hw_params_get_period_size_max (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *frames, int *dir)
int snd_pcm_hw_params_test_period_size (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t val, int dir)
int snd_pcm_hw_params_set_period_size (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t val, int dir)
int snd_pcm_hw_params_set_period_size_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val, int *dir)
int snd_pcm_hw_params_set_period_size_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val, int *dir)
int snd_pcm_hw_params_set_period_size_minmax (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *min, int *mindir, snd_pcm_uframes_t *max, int *maxdir)
int snd_pcm_hw_params_set_period_size_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val, int *dir)
int snd_pcm_hw_params_set_period_size_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val, int *dir)
int snd_pcm_hw_params_set_period_size_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val, int *dir)
int snd_pcm_hw_params_set_period_size_integer (snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
int snd_pcm_hw_params_get_periods (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_periods_min (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_periods_max (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_test_periods (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
int snd_pcm_hw_params_set_periods (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
int snd_pcm_hw_params_set_periods_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_periods_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_periods_minmax (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *min, int *mindir, unsigned int *max, int *maxdir)
int snd_pcm_hw_params_set_periods_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_periods_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_periods_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_periods_integer (snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
int snd_pcm_hw_params_get_buffer_time (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_buffer_time_min (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_buffer_time_max (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_test_buffer_time (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
int snd_pcm_hw_params_set_buffer_time (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
int snd_pcm_hw_params_set_buffer_time_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_buffer_time_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_buffer_time_minmax (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *min, int *mindir, unsigned int *max, int *maxdir)
int snd_pcm_hw_params_set_buffer_time_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_buffer_time_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_buffer_time_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_buffer_size (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
int snd_pcm_hw_params_get_buffer_size_min (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
int snd_pcm_hw_params_get_buffer_size_max (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
int snd_pcm_hw_params_test_buffer_size (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t val)
int snd_pcm_hw_params_set_buffer_size (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t val)
int snd_pcm_hw_params_set_buffer_size_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
int snd_pcm_hw_params_set_buffer_size_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
int snd_pcm_hw_params_set_buffer_size_minmax (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *min, snd_pcm_uframes_t *max)
int snd_pcm_hw_params_set_buffer_size_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
int snd_pcm_hw_params_set_buffer_size_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
int snd_pcm_hw_params_set_buffer_size_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
int snd_pcm_hw_params_get_tick_time (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_tick_time_min (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_tick_time_max (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_test_tick_time (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
int snd_pcm_hw_params_set_tick_time (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
int snd_pcm_hw_params_set_tick_time_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_tick_time_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_tick_time_minmax (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *min, int *mindir, unsigned int *max, int *maxdir)
int snd_pcm_hw_params_set_tick_time_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_tick_time_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_set_tick_time_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
int snd_pcm_hw_params_get_min_align (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)

Detailed Description

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

Define Documentation

#define snd_pcm_hw_params_alloca ptr   ) 
 

allocate an invalid snd_pcm_hw_params_t using standard alloca

Parameters:
ptr returned pointer
Examples:
/test/latency.c, and /test/pcm.c.


Function Documentation

int snd_pcm_hw_params_any snd_pcm_t pcm,
snd_pcm_hw_params_t params
 

Fill params with a full configuration space for a PCM.

Parameters:
pcm PCM handle
params Configuration space
Examples:
/test/latency.c, and /test/pcm.c.

int snd_pcm_hw_params_can_mmap_sample_resolution const snd_pcm_hw_params_t params  ) 
 

Check, if hardware supports sample-resolution mmap for given configuration.

Parameters:
param Configuration space
Returns:
Boolean value
Return values:
0 Hardware doesn't support sample-resolution mmap
1 Hardware supports sample-resolution mmap
The return value is always one when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

int snd_pcm_hw_params_can_overrange const snd_pcm_hw_params_t params  ) 
 

Check, if hardware supports overrange detection.

Parameters:
param Configuration space
Returns:
Boolean value
Return values:
0 Hardware doesn't support overrange detection
1 Hardware supports overrange detection
It is not allowed to call this function when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

int snd_pcm_hw_params_can_pause const snd_pcm_hw_params_t params  ) 
 

Check, if hardware supports pause.

Parameters:
param Configuration space
Returns:
Boolean value
Return values:
0 Hardware doesn't support pause
1 Hardware supports pause
It is not allowed to call this function when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

int snd_pcm_hw_params_can_resume const snd_pcm_hw_params_t params  ) 
 

Check, if hardware supports resume.

Parameters:
param Configuration space
Returns:
Boolean value
Return values:
0 Hardware doesn't support resume
1 Hardware supports resume
It is not allowed to call this function when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

int snd_pcm_hw_params_can_sync_start const snd_pcm_hw_params_t params  ) 
 

Check, if hardware supports synchronized start with sample resolution.

Parameters:
param Configuration space
Returns:
Boolean value
Return values:
0 Hardware doesn't support synchronized start
1 Hardware supports synchronized start
It is not allowed to call this function when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

void snd_pcm_hw_params_copy snd_pcm_hw_params_t dst,
const snd_pcm_hw_params_t src
 

copy one snd_pcm_hw_params_t to another

Parameters:
dst pointer to destination
src pointer to source
Examples:
/test/latency.c.

void snd_pcm_hw_params_free snd_pcm_hw_params_t obj  ) 
 

frees a previously allocated snd_pcm_hw_params_t

Parameters:
pointer to object to free

int snd_pcm_hw_params_get_fifo_size const snd_pcm_hw_params_t params  ) 
 

Get hard are FIFO size info from a configuration space.

Parameters:
params Configuration space
Returns:
FIFO size in frames otherwise a negative error code if the info is not available
It is not allowed to call this function when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

int snd_pcm_hw_params_get_rate_numden const snd_pcm_hw_params_t params,
unsigned int *  rate_num,
unsigned int *  rate_den
 

Get rate exact info from a configuration space.

Parameters:
params Configuration space
rate_num Pointer to returned rate numerator
rate_den Pointer to returned rate denominator
Returns:
0 otherwise a negative error code if the info is not available
It is not allowed to call this function when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

int snd_pcm_hw_params_get_sbits const snd_pcm_hw_params_t params  ) 
 

Get sample resolution info from a configuration space.

Parameters:
params Configuration space
Returns:
signification bits in sample otherwise a negative error code if the info is not available
It is not allowed to call this function when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

int snd_pcm_hw_params_is_batch const snd_pcm_hw_params_t params  ) 
 

Check, if hardware does double buffering for data transfers for given configuration.

Parameters:
param Configuration space
Returns:
Boolean value
Return values:
0 Hardware doesn't do double buffering for data transfers
1 Hardware does double buffering for data transfers
It is not allowed to call this function when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

int snd_pcm_hw_params_is_block_transfer const snd_pcm_hw_params_t params  ) 
 

Check, if hardware does block transfers for samples for given configuration.

Parameters:
param Configuration space
Returns:
Boolean value
Return values:
0 Hardware doesn't block transfers
1 Hardware does block transfers
It is not allowed to call this function when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

int snd_pcm_hw_params_is_double const snd_pcm_hw_params_t params  ) 
 

Check, if hardware does double buffering for start/stop for given configuration.

Parameters:
param Configuration space
Returns:
Boolean value
Return values:
0 Hardware doesn't do double buffering for start/stop
1 Hardware does double buffering for start/stop
It is not allowed to call this function when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

int snd_pcm_hw_params_is_half_duplex const snd_pcm_hw_params_t params  ) 
 

Check, if hardware does half-duplex only.

Parameters:
param Configuration space
Returns:
Boolean value
Return values:
0 Hardware doesn't do half-duplex
1 Hardware does half-duplex
It is not allowed to call this function when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

int snd_pcm_hw_params_is_joint_duplex const snd_pcm_hw_params_t params  ) 
 

Check, if hardware does joint-duplex (playback and capture are somewhat correlated).

Parameters:
param Configuration space
Returns:
Boolean value
Return values:
0 Hardware doesn't do joint-duplex
1 Hardware does joint-duplex
It is not allowed to call this function when given configuration is not exactly one. Usually, snd_pcm_hw_params() function chooses one configuration from the configuration space.

int snd_pcm_hw_params_malloc snd_pcm_hw_params_t **  ptr  ) 
 

allocate an invalid snd_pcm_hw_params_t using standard malloc

Parameters:
ptr returned pointer
Returns:
0 on success otherwise negative error code

size_t snd_pcm_hw_params_sizeof void   ) 
 

get size of snd_pcm_hw_params_t

Returns:
size in bytes


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