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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)
 Extract access type from a configuration space.

int snd_pcm_hw_params_test_access (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_access_t access)
 Verify if an access type is available inside a configuration space for a PCM.

int snd_pcm_hw_params_set_access (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_access_t access)
 Restrict a configuration space to contain only one access type.

int snd_pcm_hw_params_set_access_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_access_t *access)
 Restrict a configuration space to contain only its first access type.

int snd_pcm_hw_params_set_access_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_access_t *access)
 Restrict a configuration space to contain only its last access type.

int snd_pcm_hw_params_set_access_mask (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_access_mask_t *mask)
 Restrict a configuration space to contain only a set of access types.

int snd_pcm_hw_params_get_access_mask (snd_pcm_hw_params_t *params, snd_pcm_access_mask_t *mask)
 Get access mask from a configuration space.

int snd_pcm_hw_params_get_format (const snd_pcm_hw_params_t *params, snd_pcm_format_t *val)
 Extract format from a configuration space.

int snd_pcm_hw_params_test_format (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_format_t val)
 Verify if a format is available inside a configuration space for a PCM.

int snd_pcm_hw_params_set_format (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_format_t val)
 Restrict a configuration space to contain only one format.

int snd_pcm_hw_params_set_format_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_format_t *format)
 Restrict a configuration space to contain only its first format.

int snd_pcm_hw_params_set_format_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_format_t *format)
 Restrict a configuration space to contain only its last 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)
 Restrict a configuration space to contain only a set of formats.

void snd_pcm_hw_params_get_format_mask (snd_pcm_hw_params_t *params, snd_pcm_format_mask_t *mask)
 Get format mask from a configuration space.

int snd_pcm_hw_params_get_subformat (const snd_pcm_hw_params_t *params, snd_pcm_subformat_t *subformat)
 Extract subformat from a configuration space.

int snd_pcm_hw_params_test_subformat (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_subformat_t subformat)
 Verify if a subformat is available inside a configuration space for a PCM.

int snd_pcm_hw_params_set_subformat (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_subformat_t subformat)
 Restrict a configuration space to contain only one subformat.

int snd_pcm_hw_params_set_subformat_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_subformat_t *subformat)
 Restrict a configuration space to contain only its first subformat.

int snd_pcm_hw_params_set_subformat_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_subformat_t *subformat)
 Restrict a configuration space to contain only its last 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)
 Restrict a configuration space to contain only a set of subformats.

void snd_pcm_hw_params_get_subformat_mask (snd_pcm_hw_params_t *params, snd_pcm_subformat_mask_t *mask)
 Get subformat mask from a configuration space.

int snd_pcm_hw_params_get_channels (const snd_pcm_hw_params_t *params, unsigned int *val)
 Extract channels from a configuration space.

int snd_pcm_hw_params_get_channels_min (const snd_pcm_hw_params_t *params, unsigned int *val)
 Extract minimum channels count from a configuration space.

int snd_pcm_hw_params_get_channels_max (const snd_pcm_hw_params_t *params, unsigned int *val)
 Extract maximum channels count from a configuration space.

int snd_pcm_hw_params_test_channels (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val)
 Verify if a channels count is available inside a configuration space for a PCM.

int snd_pcm_hw_params_set_channels (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val)
 Restrict a configuration space to contain only one channels count.

int snd_pcm_hw_params_set_channels_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
 Restrict a configuration space with a minimum channels count.

int snd_pcm_hw_params_set_channels_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
 Restrict a configuration space with a maximum channels count.

int snd_pcm_hw_params_set_channels_minmax (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *min, unsigned int *max)
 Restrict a configuration space to have channels counts in a given range.

int snd_pcm_hw_params_set_channels_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
 Restrict a configuration space to have channels count nearest to a target.

int snd_pcm_hw_params_set_channels_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
 Restrict a configuration space to contain only its minimum channels count.

int snd_pcm_hw_params_set_channels_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
 Restrict a configuration space to contain only its maximum channels count.

int snd_pcm_hw_params_get_rate (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract rate from a configuration space.

int snd_pcm_hw_params_get_rate_min (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract minimum rate from a configuration space.

int snd_pcm_hw_params_get_rate_max (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract maximum rate from a configuration space.

int snd_pcm_hw_params_test_rate (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
 Verify if a rate is available inside a configuration space for a PCM.

int snd_pcm_hw_params_set_rate (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
 Restrict a configuration space to contain only one rate.

int snd_pcm_hw_params_set_rate_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space with a minimum rate.

int snd_pcm_hw_params_set_rate_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space with a maximum rate.

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)
 Restrict a configuration space to have rates in a given range.

int snd_pcm_hw_params_set_rate_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to have rate nearest to a target.

int snd_pcm_hw_params_set_rate_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to contain only its minimum rate.

int snd_pcm_hw_params_set_rate_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to contain only its maximum rate.

int snd_pcm_hw_params_get_period_time (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract period time from a configuration space.

int snd_pcm_hw_params_get_period_time_min (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract minimum period time from a configuration space.

int snd_pcm_hw_params_get_period_time_max (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract maximum period time from a configuration space.

int snd_pcm_hw_params_test_period_time (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
 Verify if a period time is available inside a configuration space for a PCM.

int snd_pcm_hw_params_set_period_time (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
 Restrict a configuration space to contain only one period time.

int snd_pcm_hw_params_set_period_time_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space with a minimum period time.

int snd_pcm_hw_params_set_period_time_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space with a maximum period time.

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)
 Restrict a configuration space to have period times in a given range.

int snd_pcm_hw_params_set_period_time_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to have period time nearest to a target.

int snd_pcm_hw_params_set_period_time_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to contain only its minimum period time.

int snd_pcm_hw_params_set_period_time_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to contain only its maximum period time.

int snd_pcm_hw_params_get_period_size (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *frames, int *dir)
 Extract period size from a configuration space.

int snd_pcm_hw_params_get_period_size_min (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *frames, int *dir)
 Extract minimum period size from a configuration space.

int snd_pcm_hw_params_get_period_size_max (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *frames, int *dir)
 Extract maximum period size from a configuration space.

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)
 Verify if a period size is available inside a configuration space for a PCM.

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)
 Restrict a configuration space to contain only one period size.

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)
 Restrict a configuration space with a minimum period size.

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)
 Restrict a configuration space with a maximum period size.

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)
 Restrict a configuration space to have period sizes in a given range.

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)
 Restrict a configuration space to have period size nearest to a target.

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)
 Restrict a configuration space to contain only its minimum period size.

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)
 Restrict a configuration space to contain only its maximum period size.

int snd_pcm_hw_params_set_period_size_integer (snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
 Restrict a configuration space to contain only integer period sizes.

int snd_pcm_hw_params_get_periods (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract periods from a configuration space.

int snd_pcm_hw_params_get_periods_min (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract minimum periods count from a configuration space.

int snd_pcm_hw_params_get_periods_max (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract maximum periods count from a configuration space.

int snd_pcm_hw_params_test_periods (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
 Verify if a periods count is available inside a configuration space for a PCM.

int snd_pcm_hw_params_set_periods (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
 Restrict a configuration space to contain only one periods count.

int snd_pcm_hw_params_set_periods_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space with a minimum periods count.

int snd_pcm_hw_params_set_periods_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space with a maximum periods count.

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)
 Restrict a configuration space to have periods counts in a given range.

int snd_pcm_hw_params_set_periods_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to have periods count nearest to a target.

int snd_pcm_hw_params_set_periods_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to contain only its minimum periods count.

int snd_pcm_hw_params_set_periods_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to contain only its maximum periods count.

int snd_pcm_hw_params_set_periods_integer (snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
 Restrict a configuration space to contain only integer periods counts.

int snd_pcm_hw_params_get_buffer_time (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract buffer time from a configuration space.

int snd_pcm_hw_params_get_buffer_time_min (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract minimum buffer time from a configuration space.

int snd_pcm_hw_params_get_buffer_time_max (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract maximum buffer time from a configuration space.

int snd_pcm_hw_params_test_buffer_time (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
 Verify if a buffer time is available inside a configuration space for a PCM.

int snd_pcm_hw_params_set_buffer_time (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
 Restrict a configuration space to contain only one buffer time.

int snd_pcm_hw_params_set_buffer_time_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space with a minimum buffer time.

int snd_pcm_hw_params_set_buffer_time_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space with a maximum buffer time.

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)
 Restrict a configuration space to have buffer times in a given range.

int snd_pcm_hw_params_set_buffer_time_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to have buffer time nearest to a target.

int snd_pcm_hw_params_set_buffer_time_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to contain only its minimum buffer time.

int snd_pcm_hw_params_set_buffer_time_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to contain only its maximum buffered time.

int snd_pcm_hw_params_get_buffer_size (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
 Extract buffer size from a configuration space.

int snd_pcm_hw_params_get_buffer_size_min (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
 Extract minimum buffer size from a configuration space.

int snd_pcm_hw_params_get_buffer_size_max (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
 Extract maximum buffer size from a configuration space.

int snd_pcm_hw_params_test_buffer_size (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t val)
 Verify if a buffer size is available inside a configuration space for a PCM.

int snd_pcm_hw_params_set_buffer_size (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t val)
 Restrict a configuration space to contain only one buffer size.

int snd_pcm_hw_params_set_buffer_size_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
 Restrict a configuration space with a minimum buffer size.

int snd_pcm_hw_params_set_buffer_size_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
 Restrict a configuration space with a maximum buffer size.

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)
 Restrict a configuration space to have buffer sizes in a given range.

int snd_pcm_hw_params_set_buffer_size_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
 Restrict a configuration space to have buffer size nearest to a target.

int snd_pcm_hw_params_set_buffer_size_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
 Restrict a configuration space to contain only its minimum buffer size.

int snd_pcm_hw_params_set_buffer_size_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
 Restrict a configuration space to contain only its maximum buffer size.

int snd_pcm_hw_params_get_tick_time (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract tick time from a configuration space.

int snd_pcm_hw_params_get_tick_time_min (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract minimum tick time from a configuration space.

int snd_pcm_hw_params_get_tick_time_max (const snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Extract maximum tick time from a configuration space.

int snd_pcm_hw_params_test_tick_time (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
 Verify if a tick time is available inside a configuration space for a PCM.

int snd_pcm_hw_params_set_tick_time (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val, int dir)
 Restrict a configuration space to contain only one tick time.

int snd_pcm_hw_params_set_tick_time_min (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space with a minimum tick time.

int snd_pcm_hw_params_set_tick_time_max (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space with a maximum tick time.

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)
 Restrict a configuration space to have tick times in a given range.

int snd_pcm_hw_params_set_tick_time_near (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to have tick time nearest to a target.

int snd_pcm_hw_params_set_tick_time_first (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to contain only its minimum tick time.

int snd_pcm_hw_params_set_tick_time_last (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir)
 Restrict a configuration space to contain only its maximum tick time.

int snd_pcm_hw_params_get_min_align (const snd_pcm_hw_params_t *params, snd_pcm_uframes_t *val)
 Get the minimum transfer align value in samples.


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_access const snd_pcm_hw_params_t   params,
snd_pcm_access_t   access
 

Extract access type from a configuration space.

Parameters:
params  Configuration space
access  Returned value
Returns:
access type otherwise a negative error code if not exactly one is present

int snd_pcm_hw_params_get_access_mask snd_pcm_hw_params_t   params,
snd_pcm_access_mask_t   mask
 

Get access mask from a configuration space.

Parameters:
params  Configuration space
mask  Returned Access mask

int snd_pcm_hw_params_get_buffer_size const snd_pcm_hw_params_t   params,
snd_pcm_uframes_t   val
 

Extract buffer size from a configuration space.

Parameters:
params  Configuration space
val  Returned buffer size in frames
Returns:
0 otherwise a negative error code if not exactly one is present
Examples:
/test/latency.c, and /test/pcm.c.

int snd_pcm_hw_params_get_buffer_size_max const snd_pcm_hw_params_t   params,
snd_pcm_uframes_t   val
 

Extract maximum buffer size from a configuration space.

Parameters:
params  Configuration space
val  Returned approximate maximum buffer size in frames
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

int snd_pcm_hw_params_get_buffer_size_min const snd_pcm_hw_params_t   params,
snd_pcm_uframes_t   val
 

Extract minimum buffer size from a configuration space.

Parameters:
params  Configuration space
val  Returned approximate minimum buffer size in frames
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

int snd_pcm_hw_params_get_buffer_time const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract buffer time from a configuration space.

Parameters:
params  Configuration space
approximate  buffer duration in us
val  Returned buffer time in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code if not exactly one is present
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_get_buffer_time_max const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract maximum buffer time from a configuration space.

Parameters:
params  Configuration space
val  approximate maximum buffer duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

int snd_pcm_hw_params_get_buffer_time_min const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract minimum buffer time from a configuration space.

Parameters:
params  Configuration space
val  approximate minimum buffer duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

int snd_pcm_hw_params_get_channels const snd_pcm_hw_params_t   params,
unsigned int *    val
 

Extract channels from a configuration space.

Parameters:
params  Configuration space
val  Returned channels count
Returns:
0 otherwise a negative error code if not exactly one is present

int snd_pcm_hw_params_get_channels_max const snd_pcm_hw_params_t   params,
unsigned int *    val
 

Extract maximum channels count from a configuration space.

Parameters:
params  Configuration space
val  maximum channels count
Returns:
0 otherwise a negative error code

int snd_pcm_hw_params_get_channels_min const snd_pcm_hw_params_t   params,
unsigned int *    val
 

Extract minimum channels count from a configuration space.

Parameters:
params  Configuration space
val  minimum channels count
Returns:
0 otherwise a negative error code

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_format const snd_pcm_hw_params_t   params,
snd_pcm_format_t   format
 

Extract format from a configuration space.

Parameters:
params  Configuration space
format  returned format
Returns:
format otherwise a negative error code if not exactly one is present

void snd_pcm_hw_params_get_format_mask snd_pcm_hw_params_t   params,
snd_pcm_format_mask_t   mask
 

Get format mask from a configuration space.

Parameters:
params  Configuration space
mask  Returned Format mask

int snd_pcm_hw_params_get_min_align const snd_pcm_hw_params_t   params,
snd_pcm_uframes_t   val
 

Get the minimum transfer align value in samples.

Parameters:
params  Configuration space
val  Returned minimum align value
Returns:
0 otherwise a negative error code if not exactly one is present

int snd_pcm_hw_params_get_period_size const snd_pcm_hw_params_t   params,
snd_pcm_uframes_t   val,
int *    dir
 

Extract period size from a configuration space.

Parameters:
params  Configuration space
val  Returned approximate period size in frames
dir  Sub unit direction
Returns:
0 otherwise a negative error code if not exactly one is present
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)
Examples:
/test/latency.c, and /test/pcm.c.

int snd_pcm_hw_params_get_period_size_max const snd_pcm_hw_params_t   params,
snd_pcm_uframes_t   val,
int *    dir
 

Extract maximum period size from a configuration space.

Parameters:
params  Configuration space
val  approximate minimum period size in frames
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

int snd_pcm_hw_params_get_period_size_min const snd_pcm_hw_params_t   params,
snd_pcm_uframes_t   val,
int *    dir
 

Extract minimum period size from a configuration space.

Parameters:
params  Configuration space
val  approximate minimum period size in frames
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

int snd_pcm_hw_params_get_period_time const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract period time from a configuration space.

Parameters:
params  Configuration space
val  Returned approximate period duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code if not exactly one is present
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)
Examples:
/test/latency.c.

int snd_pcm_hw_params_get_period_time_max const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract maximum period time from a configuration space.

Parameters:
params  Configuration space
val  approximate maximum period duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

int snd_pcm_hw_params_get_period_time_min const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract minimum period time from a configuration space.

Parameters:
params  Configuration space
val  approximate minimum period duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

int snd_pcm_hw_params_get_periods const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract periods from a configuration space.

Parameters:
params  Configuration space
val  approximate periods per buffer
dir  Sub unit direction
Returns:
0 otherwise a negative error code if not exactly one is present
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_get_periods_max const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract maximum periods count from a configuration space.

Parameters:
params  Configuration space
val  approximate maximum periods per buffer
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

int snd_pcm_hw_params_get_periods_min const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract minimum periods count from a configuration space.

Parameters:
params  Configuration space
val  approximate minimum periods per buffer
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

int snd_pcm_hw_params_get_rate const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract rate from a configuration space.

Parameters:
params  Configuration space
val  Returned approximate rate
dir  Sub unit direction
Returns:
0 otherwise a negative error code if not exactly one is present
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_get_rate_max const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract maximum rate from a configuration space.

Parameters:
params  Configuration space
val  Returned approximate maximum rate
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

int snd_pcm_hw_params_get_rate_min const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract minimum rate from a configuration space.

Parameters:
params  Configuration space
val  Returned approximate minimum rate
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

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_get_subformat const snd_pcm_hw_params_t   params,
snd_pcm_subformat_t   subformat
 

Extract subformat from a configuration space.

Parameters:
params  Configuration space
subformat  Returned subformat value
Returns:
subformat otherwise a negative error code if not exactly one is present

void snd_pcm_hw_params_get_subformat_mask snd_pcm_hw_params_t   params,
snd_pcm_subformat_mask_t   mask
 

Get subformat mask from a configuration space.

Parameters:
params  Configuration space
mask  Returned Subformat mask

int snd_pcm_hw_params_get_tick_time const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract tick time from a configuration space.

Parameters:
params  Configuration space
val  Returned approximate tick duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code if not exactly one is present
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)
Examples:
/test/latency.c.

int snd_pcm_hw_params_get_tick_time_max const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract maximum tick time from a configuration space.

Parameters:
params  Configuration space
val  Returned approximate maximum tick duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

int snd_pcm_hw_params_get_tick_time_min const snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Extract minimum tick time from a configuration space.

Parameters:
params  Configuration space
val  Returned approximate minimum tick duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Exact value is <,=,> the returned one following dir (-1,0,1)

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

int snd_pcm_hw_params_set_access snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_access_t    access
 

Restrict a configuration space to contain only one access type.

Parameters:
pcm  PCM handle
params  Configuration space
access  access type
Returns:
0 otherwise a negative error code if configuration space would become empty
Examples:
/test/latency.c, and /test/pcm.c.

int snd_pcm_hw_params_set_access_first snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_access_t   access
 

Restrict a configuration space to contain only its first access type.

Parameters:
pcm  PCM handle
params  Configuration space
access  Returned first access type
Returns:
0 otherwise a negative error code

int snd_pcm_hw_params_set_access_last snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_access_t   access
 

Restrict a configuration space to contain only its last access type.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned last access type
Returns:
0 otherwise a negative error code

int snd_pcm_hw_params_set_access_mask snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_access_mask_t   mask
 

Restrict a configuration space to contain only a set of access types.

Parameters:
pcm  PCM handle
params  Configuration space
mask  Access mask
Returns:
0 otherwise a negative error code

int snd_pcm_hw_params_set_buffer_size snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_uframes_t    val
 

Restrict a configuration space to contain only one buffer size.

Parameters:
pcm  PCM handle
params  Configuration space
val  buffer size in frames
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_buffer_size_first snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_uframes_t   val
 

Restrict a configuration space to contain only its minimum buffer size.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned minimum buffer size in frames
Returns:
buffer size in frames

int snd_pcm_hw_params_set_buffer_size_last snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_uframes_t   val
 

Restrict a configuration space to contain only its maximum buffer size.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned maximum buffer size in frames
Returns:
0 otherwise a negative error code

int snd_pcm_hw_params_set_buffer_size_max snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_uframes_t   val
 

Restrict a configuration space with a maximum buffer size.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate maximum buffer size in frames (on return filled with actual maximum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact minimum is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_buffer_size_min snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_uframes_t   val
 

Restrict a configuration space with a minimum buffer size.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate minimum buffer size in frames (on return filled with actual minimum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact minimum is <,=,> val following dir (-1,0,1)

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
 

Restrict a configuration space to have buffer sizes in a given range.

Parameters:
pcm  PCM handle
params  Configuration space
min  approximate minimum buffer size in frames (on return filled with actual minimum)
mindir  Sub unit direction for minimum (on return filled with actual direction)
max  approximate maximum buffer size in frames (on return filled with actual maximum)
maxdir  Sub unit direction for maximum (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact min/max is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_buffer_size_near snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_uframes_t   val
 

Restrict a configuration space to have buffer size nearest to a target.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate target buffer size in frames / returned chosen approximate target buffer size in frames
Returns:
0 otherwise a negative error code if configuration space is empty
target/chosen exact value is <,=,> val following dir (-1,0,1)
Examples:
/test/latency.c.

int snd_pcm_hw_params_set_buffer_time snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int    val,
int    dir
 

Restrict a configuration space to contain only one buffer time.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate buffer duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_buffer_time_first snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to contain only its minimum buffer time.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned approximate minimum buffer duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_set_buffer_time_last snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to contain only its maximum buffered time.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned approximate maximum buffer duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_set_buffer_time_max snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space with a maximum buffer time.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate maximum buffer duration in us (on return filled with actual maximum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact maximum is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_buffer_time_min snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space with a minimum buffer time.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate minimum buffer duration in us (on return filled with actual minimum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact minimum is <,=,> val following dir (-1,0,1)

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
 

Restrict a configuration space to have buffer times in a given range.

Parameters:
pcm  PCM handle
params  Configuration space
min  approximate minimum buffer duration in us (on return filled with actual minimum)
mindir  Sub unit direction for minimum (on return filled with actual direction)
max  approximate maximum buffer duration in us (on return filled with actual maximum)
maxdir  Sub unit direction for maximum (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact min/max is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_buffer_time_near snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to have buffer time nearest to a target.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate target buffer duration in us / returned chosen approximate target buffer duration
Returns:
0 otherwise a negative error code if configuration space is empty
target/chosen exact value is <,=,> val following dir (-1,0,1)
Examples:
/test/pcm.c.

int snd_pcm_hw_params_set_channels snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int    val
 

Restrict a configuration space to contain only one channels count.

Parameters:
pcm  PCM handle
params  Configuration space
val  channels count
Returns:
0 otherwise a negative error code if configuration space would become empty
Examples:
/test/latency.c, and /test/pcm.c.

int snd_pcm_hw_params_set_channels_first snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val
 

Restrict a configuration space to contain only its minimum channels count.

Parameters:
pcm  PCM handle
params  Configuration space
val  minimum channels count
Returns:
0 otherwise a negative error code

int snd_pcm_hw_params_set_channels_last snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val
 

Restrict a configuration space to contain only its maximum channels count.

Parameters:
pcm  PCM handle
params  Configuration space
val  maximum channels count
Returns:
0 otherwise a negative error code

int snd_pcm_hw_params_set_channels_max snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val
 

Restrict a configuration space with a maximum channels count.

Parameters:
pcm  PCM handle
params  Configuration space
val  maximum channels count (on return filled with actual maximum)
Returns:
0 otherwise a negative error code if configuration space would become empty

int snd_pcm_hw_params_set_channels_min snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val
 

Restrict a configuration space with a minimum channels count.

Parameters:
pcm  PCM handle
params  Configuration space
val  minimum channels count (on return filled with actual minimum)
Returns:
0 otherwise a negative error code if configuration space would become empty

int snd_pcm_hw_params_set_channels_minmax snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    min,
unsigned int *    max
 

Restrict a configuration space to have channels counts in a given range.

Parameters:
pcm  PCM handle
params  Configuration space
min  minimum channels count (on return filled with actual minimum)
max  maximum channels count (on return filled with actual maximum)
Returns:
0 otherwise a negative error code if configuration space would become empty

int snd_pcm_hw_params_set_channels_near snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val
 

Restrict a configuration space to have channels count nearest to a target.

Parameters:
pcm  PCM handle
params  Configuration space
val  target channels count, returned chosen channels count
Returns:
0 otherwise a negative error code if configuration space is empty

int snd_pcm_hw_params_set_format snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_format_t    format
 

Restrict a configuration space to contain only one format.

Parameters:
pcm  PCM handle
params  Configuration space
format  format
Returns:
0 otherwise a negative error code
Examples:
/test/latency.c, and /test/pcm.c.

int snd_pcm_hw_params_set_format_first snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_format_t   format
 

Restrict a configuration space to contain only its first format.

Parameters:
pcm  PCM handle
params  Configuration space
format  Returned first format
Returns:
0 otherwise a negative error code

int snd_pcm_hw_params_set_format_last snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_format_t   format
 

Restrict a configuration space to contain only its last format.

Parameters:
pcm  PCM handle
params  Configuration space
format  Returned last format
Returns:
0 otherwise a negative error code

int snd_pcm_hw_params_set_format_mask snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_format_mask_t   mask
 

Restrict a configuration space to contain only a set of formats.

Parameters:
pcm  PCM handle
params  Configuration space
mask  Format mask
Returns:
0 otherwise a negative error code

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
 

Restrict a configuration space to contain only one period size.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate period size in frames
dir  Sub unit direction
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted exact value is <,=,> val following dir (-1,0,1)

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
 

Restrict a configuration space to contain only its minimum period size.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned maximum approximate period size in frames
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_set_period_size_integer snd_pcm_t   pcm,
snd_pcm_hw_params_t   params
 

Restrict a configuration space to contain only integer period sizes.

Parameters:
pcm  PCM handle
params  Configuration space
Returns:
0 otherwise a negative error code if configuration space would become empty

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
 

Restrict a configuration space to contain only its maximum period size.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned maximum approximate period size in frames
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

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
 

Restrict a configuration space with a maximum period size.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate maximum period size in frames (on return filled with actual maximum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact minimum is <,=,> val following dir (-1,0,1)

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
 

Restrict a configuration space with a minimum period size.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate minimum period size in frames (on return filled with actual minimum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact minimum is <,=,> val following dir (-1,0,1)

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
 

Restrict a configuration space to have period sizes in a given range.

Parameters:
pcm  PCM handle
params  Configuration space
min  approximate minimum period size in frames (on return filled with actual minimum)
mindir  Sub unit direction for minimum (on return filled with actual direction)
max  approximate maximum period size in frames (on return filled with actual maximum)
maxdir  Sub unit direction for maximum (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact min/max is <,=,> val following dir (-1,0,1)

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
 

Restrict a configuration space to have period size nearest to a target.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate target period size in frames / returned chosen approximate target period size
Returns:
0 otherwise a negative error code if configuration space is empty
target/chosen exact value is <,=,> val following dir (-1,0,1)
Examples:
/test/latency.c.

int snd_pcm_hw_params_set_period_time snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int    val,
int    dir
 

Restrict a configuration space to contain only one period time.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate period duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_period_time_first snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to contain only its minimum period time.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned approximate period duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_set_period_time_last snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to contain only its maximum period time.

Parameters:
pcm  PCM handle
params  Configuration space
dir  Sub unit direction
Returns:
approximate period duration in us
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_set_period_time_max snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space with a maximum period time.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate maximum period duration in us (on return filled with actual maximum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact maximum is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_period_time_min snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space with a minimum period time.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate minimum period duration in us (on return filled with actual minimum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact minimum is <,=,> val following dir (-1,0,1)

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
 

Restrict a configuration space to have period times in a given range.

Parameters:
pcm  PCM handle
params  Configuration space
min  approximate minimum period duration in us (on return filled with actual minimum)
mindir  Sub unit direction for minimum (on return filled with actual direction)
max  approximate maximum period duration in us (on return filled with actual maximum)
maxdir  Sub unit direction for maximum (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact min/max is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_period_time_near snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to have period time nearest to a target.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate target period duration in us / returned chosen approximate target period duration
Returns:
0 otherwise a negative error code if configuration space is empty
target/chosen exact value is <,=,> val following dir (-1,0,1)
Examples:
/test/pcm.c.

int snd_pcm_hw_params_set_periods snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int    val,
int    dir
 

Restrict a configuration space to contain only one periods count.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate periods per buffer
dir  Sub unit direction
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_periods_first snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to contain only its minimum periods count.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned approximate minimum periods per buffer
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_set_periods_integer snd_pcm_t   pcm,
snd_pcm_hw_params_t   params
 

Restrict a configuration space to contain only integer periods counts.

Parameters:
pcm  PCM handle
params  Configuration space
Returns:
0 otherwise a negative error code if configuration space would become empty

int snd_pcm_hw_params_set_periods_last snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to contain only its maximum periods count.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned approximate maximum periods per buffer
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_set_periods_max snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space with a maximum periods count.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate maximum periods per buffer (on return filled with actual maximum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact maximum is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_periods_min snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space with a minimum periods count.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate minimum periods per buffer (on return filled with actual minimum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact minimum is <,=,> val following dir (-1,0,1)

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
 

Restrict a configuration space to have periods counts in a given range.

Parameters:
pcm  PCM handle
params  Configuration space
min  approximate minimum periods per buffer (on return filled with actual minimum)
mindir  Sub unit direction for minimum (on return filled with actual direction)
max  approximate maximum periods per buffer (on return filled with actual maximum)
maxdir  Sub unit direction for maximum (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact min/max is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_periods_near snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to have periods count nearest to a target.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate target periods per buffer / returned chosen approximate target periods per buffer
Returns:
0 otherwise a negative error code if configuration space is empty
target/chosen exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_rate snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int    val,
int    dir
 

Restrict a configuration space to contain only one rate.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate rate
dir  Sub unit direction
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_rate_first snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to contain only its minimum rate.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned minimum approximate rate
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_set_rate_last snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to contain only its maximum rate.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned maximum approximate rate
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_set_rate_max snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space with a maximum rate.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate maximum rate (on return filled with actual maximum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact maximum is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_rate_min snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space with a minimum rate.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate minimum rate (on return filled with actual minimum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact minimum is <,=,> val following dir (-1,0,1)

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
 

Restrict a configuration space to have rates in a given range.

Parameters:
pcm  PCM handle
params  Configuration space
min  approximate minimum rate (on return filled with actual minimum)
mindir  Sub unit direction for minimum (on return filled with actual direction)
max  approximate maximum rate (on return filled with actual maximum)
maxdir  Sub unit direction for maximum (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact min/max is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_rate_near snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to have rate nearest to a target.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate target rate / returned approximate set rate
Returns:
0 otherwise a negative error code if configuration space is empty
target/chosen exact value is <,=,> val following dir (-1,0,1)
Examples:
/test/latency.c, and /test/pcm.c.

int snd_pcm_hw_params_set_subformat snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_subformat_t    subformat
 

Restrict a configuration space to contain only one subformat.

Parameters:
pcm  PCM handle
params  Configuration space
subformat  subformat value
Returns:
0 otherwise a negative error code if configuration space would become empty

int snd_pcm_hw_params_set_subformat_first snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_subformat_t   subformat
 

Restrict a configuration space to contain only its first subformat.

Parameters:
pcm  PCM handle
params  Configuration space
subformat  Returned subformat
Returns:
0 otherwise a negative error code

int snd_pcm_hw_params_set_subformat_last snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_subformat_t   subformat
 

Restrict a configuration space to contain only its last subformat.

Parameters:
pcm  PCM handle
params  Configuration space
subformat  Returned subformat
Returns:
0 otherwise a negative error code

int snd_pcm_hw_params_set_subformat_mask snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_subformat_mask_t   mask
 

Restrict a configuration space to contain only a set of subformats.

Parameters:
pcm  PCM handle
params  Configuration space
mask  Subformat mask
Returns:
0 otherwise a negative error code

int snd_pcm_hw_params_set_tick_time snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int    val,
int    dir
 

Restrict a configuration space to contain only one tick time.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate tick duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_tick_time_first snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to contain only its minimum tick time.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned approximate minimum tick duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_set_tick_time_last snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to contain only its maximum tick time.

Parameters:
pcm  PCM handle
params  Configuration space
val  Returned approximate maximum tick duration in us
dir  Sub unit direction
Returns:
0 otherwise a negative error code
Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

int snd_pcm_hw_params_set_tick_time_max snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space with a maximum tick time.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate maximum tick duration in us (on return filled with actual maximum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact maximum is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_tick_time_min snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space with a minimum tick time.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate minimum tick duration in us (on return filled with actual minimum)
dir  Sub unit direction (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact minimum is <,=,> val following dir (-1,0,1)

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
 

Restrict a configuration space to have tick times in a given range.

Parameters:
pcm  PCM handle
params  Configuration space
min  approximate minimum tick duration in us (on return filled with actual minimum)
mindir  Sub unit direction for minimum (on return filled with actual direction)
max  approximate maximum tick duration in us (on return filled with actual maximum)
maxdir  Sub unit direction for maximum (on return filled with actual direction)
Returns:
0 otherwise a negative error code if configuration space would become empty
Wanted/actual exact min/max is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_set_tick_time_near snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int *    val,
int *    dir
 

Restrict a configuration space to have tick time nearest to a target.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate target tick duration in us / returned chosen approximate target tick duration in us
Returns:
0 otherwise a negative error code if configuration space is empty
target/chosen exact value is <,=,> val following dir (-1,0,1)

size_t snd_pcm_hw_params_sizeof void   
 

get size of snd_pcm_hw_params_t

Returns:
size in bytes

int snd_pcm_hw_params_test_access snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_access_t    access
 

Verify if an access type is available inside a configuration space for a PCM.

Parameters:
pcm  PCM handle
params  Configuration space
access  access type
Returns:
0 if available a negative error code otherwise

int snd_pcm_hw_params_test_buffer_size snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_uframes_t    val
 

Verify if a buffer size is available inside a configuration space for a PCM.

Parameters:
pcm  PCM handle
params  Configuration space
val  buffer size in frames
dir  Sub unit direction
Returns:
0 if available a negative error code otherwise
Wanted exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_test_buffer_time snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int    val,
int    dir
 

Verify if a buffer time is available inside a configuration space for a PCM.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate buffer duration in us
dir  Sub unit direction
Returns:
0 if available a negative error code otherwise
Wanted exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_test_channels snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int    val
 

Verify if a channels count is available inside a configuration space for a PCM.

Parameters:
pcm  PCM handle
params  Configuration space
val  channels count
Returns:
0 if available a negative error code otherwise

int snd_pcm_hw_params_test_format snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_format_t    format
 

Verify if a format is available inside a configuration space for a PCM.

Parameters:
pcm  PCM handle
params  Configuration space
format  format
Returns:
0 if available a negative error code otherwise

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
 

Verify if a period size is available inside a configuration space for a PCM.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate period size in frames
dir  Sub unit direction
Returns:
0 if available a negative error code otherwise
Wanted exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_test_period_time snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int    val,
int    dir
 

Verify if a period time is available inside a configuration space for a PCM.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate period duration in us
dir  Sub unit direction
Returns:
0 if available a negative error code otherwise
Wanted exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_test_periods snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int    val,
int    dir
 

Verify if a periods count is available inside a configuration space for a PCM.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate periods per buffer
dir  Sub unit direction
Returns:
0 if available a negative error code otherwise
Wanted exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_test_rate snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int    val,
int    dir
 

Verify if a rate is available inside a configuration space for a PCM.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate rate
dir  Sub unit direction
Returns:
0 if available a negative error code otherwise
Wanted exact value is <,=,> val following dir (-1,0,1)

int snd_pcm_hw_params_test_subformat snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
snd_pcm_subformat_t    subformat
 

Verify if a subformat is available inside a configuration space for a PCM.

Parameters:
pcm  PCM handle
params  Configuration space
subformat  subformat value
Returns:
0 if available a negative error code otherwise

int snd_pcm_hw_params_test_tick_time snd_pcm_t   pcm,
snd_pcm_hw_params_t   params,
unsigned int    val,
int    dir
 

Verify if a tick time is available inside a configuration space for a PCM.

Parameters:
pcm  PCM handle
params  Configuration space
val  approximate tick duration in us
dir  Sub unit direction
Returns:
0 if available a negative error code otherwise
Wanted exact value is <,=,> val following dir (-1,0,1)


Generated on Fri Sep 3 11:05:47 2004 for ALSA project - the C library reference by doxygen1.2.18