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_is_monotonic (const snd_pcm_hw_params_t *params)
	Check, if timestamps are monotonic 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_forward (const snd_pcm_hw_params_t *params)
int	snd_pcm_hw_params_can_rewind (const snd_pcm_hw_params_t *params)
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_set_rate_resample (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val)
	Restrict a configuration space to contain only real hardware rates.
int	snd_pcm_hw_params_get_rate_resample (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
	Extract resample state from a configuration space.
int	snd_pcm_hw_params_set_export_buffer (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val)
	Restrict a configuration space to allow the buffer accessible from outside.
int	snd_pcm_hw_params_get_export_buffer (snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
	Extract buffer accessibility from a configuration space.
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_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:

params

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:

params

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:

params

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:

params

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:

params

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:

obj

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

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

Returns:

0 otherwise a negative error code

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
	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_export_buffer	(	snd_pcm_t *	pcm,
		snd_pcm_hw_params_t *	params,
		unsigned int *	val
	)

Extract buffer accessibility from a configuration space.

Parameters:

	pcm	PCM handle
	params	Configuration space
	val	0 = disable, 1 = enable exporting buffer

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