PCM Interface. More...

Functions
const char *	snd_pcm_name (snd_pcm_t *pcm)
	get identifier of PCM handle

snd_pcm_type_t	snd_pcm_type (snd_pcm_t *pcm)
	get type of PCM handle

snd_pcm_stream_t	snd_pcm_stream (snd_pcm_t *pcm)
	get stream for a PCM handle

int	snd_pcm_close (snd_pcm_t *pcm)
	close PCM handle

int	snd_pcm_nonblock (snd_pcm_t *pcm, int nonblock)
	set nonblock mode

int	snd_pcm_info (snd_pcm_t pcm, snd_pcm_info_t info)
	Obtain general (static) information for PCM handle.

int	snd_pcm_hw_params_current (snd_pcm_t pcm, snd_pcm_hw_params_t params)
	Retreive current PCM hardware configuration chosen with snd_pcm_hw_params.

int	snd_pcm_hw_params (snd_pcm_t pcm, snd_pcm_hw_params_t params)
	Install one PCM hardware configuration chosen from a configuration space and snd_pcm_prepare it.

int	snd_pcm_hw_free (snd_pcm_t *pcm)
	Remove PCM hardware configuration and free associated resources.

int	snd_pcm_sw_params (snd_pcm_t pcm, snd_pcm_sw_params_t params)
	Install PCM software configuration defined by params.

int	snd_pcm_status (snd_pcm_t pcm, snd_pcm_status_t status)
	Obtain status (runtime) information for PCM handle.

snd_pcm_state_t	snd_pcm_state (snd_pcm_t *pcm)
	Return PCM state.

int	snd_pcm_hwsync (snd_pcm_t *pcm)
	(DEPRECATED) Synchronize stream position with hardware

int	snd_pcm_delay (snd_pcm_t pcm, snd_pcm_sframes_t delayp)
	Obtain delay for a running PCM handle.

int	snd_pcm_resume (snd_pcm_t *pcm)
	Resume from suspend, no samples are lost.

int	snd_pcm_htimestamp (snd_pcm_t pcm, snd_pcm_uframes_t avail, snd_htimestamp_t *tstamp)
	Obtain last position update hi-res timestamp.

int	snd_pcm_prepare (snd_pcm_t *pcm)
	Prepare PCM for use.

int	snd_pcm_reset (snd_pcm_t *pcm)
	Reset PCM position.

int	snd_pcm_start (snd_pcm_t *pcm)
	Start a PCM.

int	snd_pcm_drop (snd_pcm_t *pcm)
	Stop a PCM dropping pending frames.

int	snd_pcm_drain (snd_pcm_t *pcm)
	Stop a PCM preserving pending frames.

int	snd_pcm_pause (snd_pcm_t *pcm, int enable)
	Pause/resume PCM.

snd_pcm_sframes_t	snd_pcm_rewindable (snd_pcm_t *pcm)
	Get safe count of frames which can be rewinded.

snd_pcm_sframes_t	snd_pcm_rewind (snd_pcm_t *pcm, snd_pcm_uframes_t frames)
	Move application frame position backward.

snd_pcm_sframes_t	snd_pcm_forwardable (snd_pcm_t *pcm)
	Get safe count of frames which can be forwarded.

snd_pcm_sframes_t	snd_pcm_forward (snd_pcm_t *pcm, snd_pcm_uframes_t frames)
	Move application frame position forward.

snd_pcm_sframes_t	snd_pcm_writei (snd_pcm_t pcm, const void buffer, snd_pcm_uframes_t size)
	Write interleaved frames to a PCM.

snd_pcm_sframes_t	snd_pcm_writen (snd_pcm_t pcm, void *bufs, snd_pcm_uframes_t size)
	Write non interleaved frames to a PCM.

snd_pcm_sframes_t	snd_pcm_readi (snd_pcm_t pcm, void buffer, snd_pcm_uframes_t size)
	Read interleaved frames from a PCM.

snd_pcm_sframes_t	snd_pcm_readn (snd_pcm_t pcm, void *bufs, snd_pcm_uframes_t size)
	Read non interleaved frames to a PCM.

int	snd_pcm_link (snd_pcm_t pcm1, snd_pcm_t pcm2)
	Link two PCMs.

int	snd_pcm_unlink (snd_pcm_t *pcm)
	Remove a PCM from a linked group.

int	snd_pcm_poll_descriptors_count (snd_pcm_t *pcm)
	get count of poll descriptors for PCM handle

int	snd_pcm_poll_descriptors (snd_pcm_t pcm, struct pollfd pfds, unsigned int space)
	get poll descriptors

int	snd_pcm_poll_descriptors_revents (snd_pcm_t pcm, struct pollfd pfds, unsigned int nfds, unsigned short *revents)
	get returned events from poll descriptors

const char *	snd_pcm_stream_name (const snd_pcm_stream_t stream)
	get name of PCM stream type

const char *	snd_pcm_access_name (const snd_pcm_access_t acc)
	get name of PCM access type

const char *	snd_pcm_format_name (const snd_pcm_format_t format)
	get name of PCM sample format

const char *	snd_pcm_format_description (const snd_pcm_format_t format)
	get description of PCM sample format

snd_pcm_format_t	snd_pcm_format_value (const char *name)
	get PCM sample format from name

const char *	snd_pcm_subformat_name (const snd_pcm_subformat_t subformat)
	get name of PCM sample subformat

const char *	snd_pcm_subformat_description (const snd_pcm_subformat_t subformat)
	get description of PCM sample subformat

snd_pcm_subformat_t	snd_pcm_subformat_value (const char *name)
	get PCM sample subformat from name

const char *	snd_pcm_start_mode_name (snd_pcm_start_t mode)
	(DEPRECATED) get name of PCM start mode setting

const char *	snd_pcm_xrun_mode_name (snd_pcm_xrun_t mode)
	(DEPRECATED) get name of PCM xrun mode setting

const char *	snd_pcm_tstamp_mode_name (const snd_pcm_tstamp_t mode)
	get name of PCM tstamp mode setting

const char *	snd_pcm_tstamp_type_name (snd_pcm_tstamp_type_t type)
	get name of PCM tstamp type setting

const char *	snd_pcm_state_name (const snd_pcm_state_t state)
	get name of PCM state

const char *	snd_pcm_type_name (snd_pcm_type_t type)
	get name of PCM type

int	snd_pcm_dump_hw_setup (snd_pcm_t pcm, snd_output_t out)
	Dump current hardware setup for PCM.

int	snd_pcm_dump_sw_setup (snd_pcm_t pcm, snd_output_t out)
	Dump current software setup for PCM.

int	snd_pcm_dump_setup (snd_pcm_t pcm, snd_output_t out)
	Dump current setup (hardware and software) for PCM.

int	snd_pcm_status_dump (snd_pcm_status_t status, snd_output_t out)
	Dump status.

int	snd_pcm_dump (snd_pcm_t pcm, snd_output_t out)
	Dump PCM info.

snd_pcm_sframes_t	snd_pcm_bytes_to_frames (snd_pcm_t *pcm, ssize_t bytes)
	Convert bytes in frames for a PCM.

ssize_t	snd_pcm_frames_to_bytes (snd_pcm_t *pcm, snd_pcm_sframes_t frames)
	Convert frames in bytes for a PCM.

long	snd_pcm_bytes_to_samples (snd_pcm_t *pcm, ssize_t bytes)
	Convert bytes in samples for a PCM.

ssize_t	snd_pcm_samples_to_bytes (snd_pcm_t *pcm, long samples)
	Convert samples in bytes for a PCM.

int	snd_async_add_pcm_handler (snd_async_handler_t *handler, snd_pcm_t pcm, snd_async_callback_t callback, void *private_data)
	Add an async handler for a PCM.

snd_pcm_t *	snd_async_handler_get_pcm (snd_async_handler_t *handler)
	Return PCM handle related to an async handler.

int	snd_pcm_open (snd_pcm_t *pcmp, const char name, snd_pcm_stream_t stream, int mode)
	Opens a PCM.

int	snd_pcm_open_lconf (snd_pcm_t *pcmp, const char name, snd_pcm_stream_t stream, int mode, snd_config_t *lconf)
	Opens a PCM using local configuration.

int	snd_pcm_open_fallback (snd_pcm_t *pcmp, snd_config_t root, const char name, const char orig_name, snd_pcm_stream_t stream, int mode)
	Opens a fallback PCM.

int	snd_pcm_wait (snd_pcm_t *pcm, int timeout)
	Wait for a PCM to become ready.

snd_pcm_sframes_t	snd_pcm_avail_update (snd_pcm_t *pcm)
	Return number of frames ready to be read (capture) / written (playback)

snd_pcm_sframes_t	snd_pcm_avail (snd_pcm_t *pcm)
	Return number of frames ready to be read (capture) / written (playback)

int	snd_pcm_avail_delay (snd_pcm_t pcm, snd_pcm_sframes_t availp, snd_pcm_sframes_t *delayp)
	Combine snd_pcm_avail and snd_pcm_delay functions.

int	snd_pcm_area_silence (const snd_pcm_channel_area_t *dst_area, snd_pcm_uframes_t dst_offset, unsigned int samples, snd_pcm_format_t format)
	Silence an area.

int	snd_pcm_areas_silence (const snd_pcm_channel_area_t *dst_areas, snd_pcm_uframes_t dst_offset, unsigned int channels, snd_pcm_uframes_t frames, snd_pcm_format_t format)
	Silence one or more areas.

int	snd_pcm_area_copy (const snd_pcm_channel_area_t dst_area, snd_pcm_uframes_t dst_offset, const snd_pcm_channel_area_t src_area, snd_pcm_uframes_t src_offset, unsigned int samples, snd_pcm_format_t format)
	Copy an area.

int	snd_pcm_areas_copy (const snd_pcm_channel_area_t dst_areas, snd_pcm_uframes_t dst_offset, const snd_pcm_channel_area_t src_areas, snd_pcm_uframes_t src_offset, unsigned int channels, snd_pcm_uframes_t frames, snd_pcm_format_t format)
	Copy one or more areas.

int	snd_pcm_areas_copy_wrap (const snd_pcm_channel_area_t dst_channels, snd_pcm_uframes_t dst_offset, const snd_pcm_uframes_t dst_size, const snd_pcm_channel_area_t src_channels, snd_pcm_uframes_t src_offset, const snd_pcm_uframes_t src_size, const unsigned int channels, snd_pcm_uframes_t frames, const snd_pcm_format_t format)
	Copy one or more areas.

int	snd_pcm_hw_params_dump (snd_pcm_hw_params_t params, snd_output_t out)
	Dump a PCM hardware configuration space.

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_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_can_disable_period_wakeup (const snd_pcm_hw_params_t *params)
	Check if hardware can disable period wakeups.

int	snd_pcm_hw_params_is_perfect_drain (const snd_pcm_hw_params_t *params)
	Check if hardware is capable of perfect drain.

int	snd_pcm_hw_params_supports_audio_wallclock_ts (const snd_pcm_hw_params_t *params)
	Check if hardware supports audio wallclock timestamps.

int	snd_pcm_hw_params_supports_audio_ts_type (const snd_pcm_hw_params_t *params, int type)
	Check if hardware supports type of audio timestamps.

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 hardware FIFO size info from a configuration space.

const unsigned char *	snd_pcm_hw_params_get_sync (const snd_pcm_hw_params_t *params)
	Get hardware synchronization ID from a PCM info container.

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.

size_t	snd_pcm_access_mask_sizeof ()
	get size of snd_pcm_access_mask_t

int	snd_pcm_access_mask_malloc (snd_pcm_access_mask_t **ptr)
	allocate an empty snd_pcm_access_mask_t using standard malloc

void	snd_pcm_access_mask_free (snd_pcm_access_mask_t *obj)
	frees a previously allocated snd_pcm_access_mask_t

void	snd_pcm_access_mask_copy (snd_pcm_access_mask_t dst, const snd_pcm_access_mask_t src)
	copy one snd_pcm_access_mask_t to another

void	snd_pcm_access_mask_none (snd_pcm_access_mask_t *mask)
	reset all bits in a snd_pcm_access_mask_t

void	snd_pcm_access_mask_any (snd_pcm_access_mask_t *mask)
	set all bits in a snd_pcm_access_mask_t

int	snd_pcm_access_mask_test (const snd_pcm_access_mask_t *mask, snd_pcm_access_t val)
	test the presence of an access type in a snd_pcm_access_mask_t

int	snd_pcm_access_mask_empty (const snd_pcm_access_mask_t *mask)
	test, if given a snd_pcm_access_mask_t is empty

void	snd_pcm_access_mask_set (snd_pcm_access_mask_t *mask, snd_pcm_access_t val)
	make an access type present in a snd_pcm_access_mask_t

void	snd_pcm_access_mask_reset (snd_pcm_access_mask_t *mask, snd_pcm_access_t val)
	make an access type missing from a snd_pcm_access_mask_t

size_t	snd_pcm_format_mask_sizeof ()
	get size of snd_pcm_format_mask_t

int	snd_pcm_format_mask_malloc (snd_pcm_format_mask_t **ptr)
	allocate an empty snd_pcm_format_mask_t using standard malloc

void	snd_pcm_format_mask_free (snd_pcm_format_mask_t *obj)
	frees a previously allocated snd_pcm_format_mask_t

void	snd_pcm_format_mask_copy (snd_pcm_format_mask_t dst, const snd_pcm_format_mask_t src)
	copy one snd_pcm_format_mask_t to another

void	snd_pcm_format_mask_none (snd_pcm_format_mask_t *mask)
	reset all bits in a snd_pcm_format_mask_t

void	snd_pcm_format_mask_any (snd_pcm_format_mask_t *mask)
	set all bits in a snd_pcm_format_mask_t

int	snd_pcm_format_mask_test (const snd_pcm_format_mask_t *mask, snd_pcm_format_t val)
	test the presence of a format in a snd_pcm_format_mask_t

int	snd_pcm_format_mask_empty (const snd_pcm_format_mask_t *mask)
	test, if given a snd_pcm_format_mask_t is empty

void	snd_pcm_format_mask_set (snd_pcm_format_mask_t *mask, snd_pcm_format_t val)
	make a format present in a snd_pcm_format_mask_t

void	snd_pcm_format_mask_reset (snd_pcm_format_mask_t *mask, snd_pcm_format_t val)
	make a format missing from a snd_pcm_format_mask_t

size_t	snd_pcm_subformat_mask_sizeof ()
	get size of snd_pcm_subformat_mask_t

int	snd_pcm_subformat_mask_malloc (snd_pcm_subformat_mask_t **ptr)
	allocate an empty snd_pcm_subformat_mask_t using standard malloc

void	snd_pcm_subformat_mask_free (snd_pcm_subformat_mask_t *obj)
	frees a previously allocated snd_pcm_subformat_mask_t

void	snd_pcm_subformat_mask_copy (snd_pcm_subformat_mask_t dst, const snd_pcm_subformat_mask_t src)
	copy one snd_pcm_subformat_mask_t to another

void	snd_pcm_subformat_mask_none (snd_pcm_subformat_mask_t *mask)
	reset all bits in a snd_pcm_subformat_mask_t

void	snd_pcm_subformat_mask_any (snd_pcm_subformat_mask_t *mask)
	set all bits in a snd_pcm_subformat_mask_t

int	snd_pcm_subformat_mask_test (const snd_pcm_subformat_mask_t *mask, snd_pcm_subformat_t val)
	test the presence of a subformat in a snd_pcm_subformat_mask_t

int	snd_pcm_subformat_mask_empty (const snd_pcm_subformat_mask_t *mask)
	test, if given a snd_pcm_subformat_mask_t is empty

void	snd_pcm_subformat_mask_set (snd_pcm_subformat_mask_t *mask, snd_pcm_subformat_t val)
	make a subformat present in a snd_pcm_subformat_mask_t

void	snd_pcm_subformat_mask_reset (snd_pcm_subformat_mask_t *mask, snd_pcm_subformat_t val)
	make a subformat missing from a snd_pcm_subformat_mask_t

size_t	snd_pcm_hw_params_sizeof ()
	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 format)
	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 format)
	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 format)
	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 to be 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_set_period_wakeup (snd_pcm_t pcm, snd_pcm_hw_params_t params, unsigned int val)
	Restrict a configuration space to settings without period wakeups.

int	snd_pcm_hw_params_get_period_wakeup (snd_pcm_t pcm, snd_pcm_hw_params_t params, unsigned int *val)
	Extract period wakeup flag from a configuration space.

int	snd_pcm_hw_params_set_drain_silence (snd_pcm_t pcm, snd_pcm_hw_params_t params, unsigned int val)
	Restrict a configuration space to fill the end of playback stream with silence when drain() is invoked.

int	snd_pcm_hw_params_get_drain_silence (snd_pcm_t pcm, snd_pcm_hw_params_t params, unsigned int *val)
	Extract drain with the filling of silence samples 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 val, 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 val, 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 val, 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)
	(DEPRECATED) 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)
	(DEPRECATED) 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)
	(DEPRECATED) 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)
	(DEPRECATED) 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)
	(DEPRECATED) 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)
	(DEPRECATED) 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)
	(DEPRECATED) 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)
	(DEPRECATED) 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)
	(DEPRECATED) 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)
	(DEPRECATED) 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)
	(DEPRECATED) 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.

int	snd_pcm_sw_params_current (snd_pcm_t pcm, snd_pcm_sw_params_t params)
	Return current software configuration for a PCM.

int	snd_pcm_sw_params_dump (snd_pcm_sw_params_t params, snd_output_t out)
	Dump a software configuration.

size_t	snd_pcm_sw_params_sizeof ()
	get size of snd_pcm_sw_params_t

int	snd_pcm_sw_params_malloc (snd_pcm_sw_params_t **ptr)
	allocate an invalid snd_pcm_sw_params_t using standard malloc

void	snd_pcm_sw_params_free (snd_pcm_sw_params_t *obj)
	frees a previously allocated snd_pcm_sw_params_t

void	snd_pcm_sw_params_copy (snd_pcm_sw_params_t dst, const snd_pcm_sw_params_t src)
	copy one snd_pcm_sw_params_t to another

int	snd_pcm_sw_params_get_boundary (const snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	Get boundary for ring pointers from a software configuration container.

int	snd_pcm_sw_params_set_start_mode (snd_pcm_t pcm, snd_pcm_sw_params_t params, snd_pcm_start_t val)
	(DEPRECATED) Set start mode inside a software configuration container

snd_pcm_start_t	snd_pcm_sw_params_get_start_mode (const snd_pcm_sw_params_t *params)
	(DEPRECATED) Get start mode from a software configuration container

int	snd_pcm_sw_params_set_xrun_mode (snd_pcm_t pcm, snd_pcm_sw_params_t params, snd_pcm_xrun_t val)
	(DEPRECATED) Set xrun mode inside a software configuration container

snd_pcm_xrun_t	snd_pcm_sw_params_get_xrun_mode (const snd_pcm_sw_params_t *params)
	(DEPRECATED) Get xrun mode from a software configuration container

int	snd_pcm_sw_params_set_tstamp_mode (snd_pcm_t pcm, snd_pcm_sw_params_t params, snd_pcm_tstamp_t val)
	Set timestamp mode inside a software configuration container.

int	snd_pcm_sw_params_get_tstamp_mode (const snd_pcm_sw_params_t params, snd_pcm_tstamp_t val)
	Get timestamp mode from a software configuration container.

int	snd_pcm_sw_params_set_tstamp_type (snd_pcm_t pcm, snd_pcm_sw_params_t params, snd_pcm_tstamp_type_t val)
	Set timestamp type inside a software configuration container.

int	snd_pcm_sw_params_get_tstamp_type (const snd_pcm_sw_params_t params, snd_pcm_tstamp_type_t val)
	Get timestamp type from a software configuration container.

int	snd_pcm_sw_params_set_sleep_min (snd_pcm_t pcm, snd_pcm_sw_params_t params, unsigned int val)
	(DEPRECATED) Set minimum number of ticks to sleep inside a software configuration container

int	snd_pcm_sw_params_get_sleep_min (const snd_pcm_sw_params_t params, unsigned int val)
	(DEPRECATED) Get minimum numbers of ticks to sleep from a software configuration container

int	snd_pcm_sw_params_set_avail_min (snd_pcm_t pcm, snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	Set avail min inside a software configuration container.

int	snd_pcm_sw_params_get_avail_min (const snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	Get avail min from a software configuration container.

int	snd_pcm_sw_params_set_period_event (snd_pcm_t pcm, snd_pcm_sw_params_t params, int val)
	Set period event inside a software configuration container.

int	snd_pcm_sw_params_get_period_event (const snd_pcm_sw_params_t params, int val)
	Get period event from a software configuration container.

int	snd_pcm_sw_params_set_xfer_align (snd_pcm_t pcm, snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	(DEPRECATED) Set xfer align inside a software configuration container

int	snd_pcm_sw_params_get_xfer_align (const snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	(DEPRECATED) Get xfer align from a software configuration container

int	snd_pcm_sw_params_set_start_threshold (snd_pcm_t pcm, snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	Set start threshold inside a software configuration container.

int	snd_pcm_sw_params_get_start_threshold (const snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	Get start threshold from a software configuration container.

int	snd_pcm_sw_params_set_stop_threshold (snd_pcm_t pcm, snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	Set stop threshold inside a software configuration container.

int	snd_pcm_sw_params_get_stop_threshold (const snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	Get stop threshold from a software configuration container.

int	snd_pcm_sw_params_set_silence_threshold (snd_pcm_t pcm, snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	Set silence threshold inside a software configuration container.

int	snd_pcm_sw_params_get_silence_threshold (const snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	Get silence threshold from a software configuration container.

int	snd_pcm_sw_params_set_silence_size (snd_pcm_t pcm, snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	Set silence size inside a software configuration container.

int	snd_pcm_sw_params_get_silence_size (const snd_pcm_sw_params_t params, snd_pcm_uframes_t val)
	Get silence size from a software configuration container.

size_t	snd_pcm_status_sizeof ()
	get size of snd_pcm_status_t

int	snd_pcm_status_malloc (snd_pcm_status_t **ptr)
	allocate an invalid snd_pcm_status_t using standard malloc

void	snd_pcm_status_free (snd_pcm_status_t *obj)
	frees a previously allocated snd_pcm_status_t

void	snd_pcm_status_copy (snd_pcm_status_t dst, const snd_pcm_status_t src)
	copy one snd_pcm_status_t to another

snd_pcm_state_t	snd_pcm_status_get_state (const snd_pcm_status_t *obj)
	Get state from a PCM status container (see snd_pcm_state)

void	snd_pcm_status_get_trigger_tstamp (const snd_pcm_status_t obj, snd_timestamp_t ptr)
	Get trigger timestamp from a PCM status container.

void	snd_pcm_status_get_trigger_htstamp (const snd_pcm_status_t obj, snd_htimestamp_t ptr)
	Get trigger hi-res timestamp from a PCM status container.

void	snd_pcm_status_get_tstamp (const snd_pcm_status_t obj, snd_timestamp_t ptr)
	Get "now" timestamp from a PCM status container.

void	snd_pcm_status_get_htstamp (const snd_pcm_status_t obj, snd_htimestamp_t ptr)
	Get "now" hi-res timestamp from a PCM status container.

void	snd_pcm_status_get_audio_htstamp (const snd_pcm_status_t obj, snd_htimestamp_t ptr)
	Get "now" hi-res audio timestamp from a PCM status container.

void	snd_pcm_status_get_driver_htstamp (const snd_pcm_status_t obj, snd_htimestamp_t ptr)
	Get "now" hi-res driver timestamp from a PCM status container. Defines when the status was generated by driver, may differ from normal timestamp.

void	snd_pcm_status_get_audio_htstamp_report (const snd_pcm_status_t obj, snd_pcm_audio_tstamp_report_t audio_tstamp_report)
	Get audio_tstamp_report from a PCM status container.

void	snd_pcm_status_set_audio_htstamp_config (snd_pcm_status_t obj, snd_pcm_audio_tstamp_config_t audio_tstamp_config)
	set audio_tstamp_config from a PCM status container

snd_pcm_sframes_t	snd_pcm_status_get_delay (const snd_pcm_status_t *obj)
	Get delay from a PCM status container (see snd_pcm_delay)

snd_pcm_uframes_t	snd_pcm_status_get_avail (const snd_pcm_status_t *obj)
	Get number of frames available from a PCM status container (see snd_pcm_avail_update)

snd_pcm_uframes_t	snd_pcm_status_get_avail_max (const snd_pcm_status_t *obj)
	Get maximum number of frames available from a PCM status container after last snd_pcm_status call.

snd_pcm_uframes_t	snd_pcm_status_get_overrange (const snd_pcm_status_t *obj)
	Get count of ADC overrange detections since last call.

size_t	snd_pcm_info_sizeof ()
	get size of snd_pcm_info_t

int	snd_pcm_info_malloc (snd_pcm_info_t **ptr)
	allocate an invalid snd_pcm_info_t using standard malloc

void	snd_pcm_info_free (snd_pcm_info_t *obj)
	frees a previously allocated snd_pcm_info_t

void	snd_pcm_info_copy (snd_pcm_info_t dst, const snd_pcm_info_t src)
	copy one snd_pcm_info_t to another

unsigned int	snd_pcm_info_get_device (const snd_pcm_info_t *obj)
	Get device from a PCM info container.

unsigned int	snd_pcm_info_get_subdevice (const snd_pcm_info_t *obj)
	Get subdevice from a PCM info container.

snd_pcm_stream_t	snd_pcm_info_get_stream (const snd_pcm_info_t *obj)
	Get stream (direction) from a PCM info container.

int	snd_pcm_info_get_card (const snd_pcm_info_t *obj)
	Get card from a PCM info container.

const char *	snd_pcm_info_get_id (const snd_pcm_info_t *obj)
	Get id from a PCM info container.

const char *	snd_pcm_info_get_name (const snd_pcm_info_t *obj)
	Get name from a PCM info container.

const char *	snd_pcm_info_get_subdevice_name (const snd_pcm_info_t *obj)
	Get subdevice name from a PCM info container.

snd_pcm_class_t	snd_pcm_info_get_class (const snd_pcm_info_t *obj)
	Get class from a PCM info container.

snd_pcm_subclass_t	snd_pcm_info_get_subclass (const snd_pcm_info_t *obj)
	Get subclass from a PCM info container.

unsigned int	snd_pcm_info_get_subdevices_count (const snd_pcm_info_t *obj)
	Get subdevices count from a PCM info container.

unsigned int	snd_pcm_info_get_subdevices_avail (const snd_pcm_info_t *obj)
	Get available subdevices count from a PCM info container.

snd_pcm_sync_id_t	snd_pcm_info_get_sync (const snd_pcm_info_t *obj)
	(DEPRECATED) Get hardware synchronization ID from a PCM info container

void	snd_pcm_info_set_device (snd_pcm_info_t *obj, unsigned int val)
	Set wanted device inside a PCM info container (see snd_ctl_pcm_info)

void	snd_pcm_info_set_subdevice (snd_pcm_info_t *obj, unsigned int val)
	Set wanted subdevice inside a PCM info container (see snd_ctl_pcm_info)

void	snd_pcm_info_set_stream (snd_pcm_info_t *obj, snd_pcm_stream_t val)
	Set wanted stream inside a PCM info container (see snd_ctl_pcm_info)

int	snd_pcm_mmap_begin (snd_pcm_t pcm, const snd_pcm_channel_area_t areas, snd_pcm_uframes_t offset, snd_pcm_uframes_t *frames)
	Application request to access a portion of direct (mmap) area.

snd_pcm_sframes_t	snd_pcm_mmap_commit (snd_pcm_t *pcm, snd_pcm_uframes_t offset, snd_pcm_uframes_t frames)
	Application has completed the access to area requested with snd_pcm_mmap_begin.

snd_pcm_chmap_query_t **	snd_pcm_query_chmaps (snd_pcm_t *pcm)

void	snd_pcm_free_chmaps (snd_pcm_chmap_query_t **maps)

snd_pcm_chmap_t *	snd_pcm_get_chmap (snd_pcm_t *pcm)

int	snd_pcm_set_chmap (snd_pcm_t pcm, const snd_pcm_chmap_t map)

const char *	snd_pcm_chmap_type_name (enum snd_pcm_chmap_type val)

const char *	snd_pcm_chmap_name (enum snd_pcm_chmap_position val)

const char *	snd_pcm_chmap_long_name (enum snd_pcm_chmap_position val)

int	snd_pcm_chmap_print (const snd_pcm_chmap_t map, size_t maxlen, char buf)

unsigned int	snd_pcm_chmap_from_string (const char *str)

snd_pcm_chmap_t *	snd_pcm_chmap_parse_string (const char *str)

int	snd_pcm_recover (snd_pcm_t *pcm, int err, int silent)
	Recover the stream state from an error or suspend.

int	snd_pcm_set_params (snd_pcm_t *pcm, snd_pcm_format_t format, snd_pcm_access_t access, unsigned int channels, unsigned int rate, int soft_resample, unsigned int latency)
	Set the hardware and software parameters in a simple way.

int	snd_pcm_get_params (snd_pcm_t pcm, snd_pcm_uframes_t buffer_size, snd_pcm_uframes_t *period_size)
	Get the transfer size parameters in a simple way.

Detailed Description

PCM Interface.

Author: Jaroslav Kysela perex.nosp@m.@per.nosp@m.ex.cz; Abramo Bagnara abram.nosp@m.o@al.nosp@m.sa-pr.nosp@m.ojec.nosp@m.t.org

Date: 2000-2001

PCM Interface is designed to write or read digital audio frames. A frame is the data unit converted into/from sound in one time unit (1/rate seconds), by example if you set your playback PCM rate to 44100 you'll hear 44100 frames per second. The size in bytes of a frame may be obtained from bits needed to store a sample and channels count.

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

Function Documentation

◆ snd_pcm_hw_params_get_access()

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 the configuration space does not contain a single value

◆ snd_pcm_hw_params_get_access_mask()

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

◆ snd_pcm_hw_params_get_buffer_size()

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 the configuration space does not contain a single value

Examples: /test/latency.c, and /test/pcm.c.

◆ snd_pcm_hw_params_get_buffer_size_max()

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)

◆ snd_pcm_hw_params_get_buffer_size_min()

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

◆ snd_pcm_hw_params_get_buffer_time()

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 the configuration space does not contain a single value

Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

◆ snd_pcm_hw_params_get_buffer_time_max()

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)

◆ snd_pcm_hw_params_get_buffer_time_min()

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)

◆ snd_pcm_hw_params_get_channels()

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 the configuration space does not contain a single value

◆ snd_pcm_hw_params_get_channels_max()

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

◆ snd_pcm_hw_params_get_channels_min()

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

◆ snd_pcm_hw_params_get_drain_silence()

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

Extract drain with the filling of silence samples from a configuration space.

Parameters

pcm	PCM handle
params	Configuration space
val	0 = disabled, 1 = enabled

Returns: 0 otherwise a negative error code

◆ snd_pcm_hw_params_get_export_buffer()

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

◆ snd_pcm_hw_params_get_format()

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 the configuration space does not contain a single value

◆ snd_pcm_hw_params_get_format_mask()

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

◆ snd_pcm_hw_params_get_period_size()

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 the configuration space does not contain a single value

Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

Examples: /test/latency.c, and /test/pcm.c.

◆ snd_pcm_hw_params_get_period_size_max()

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)

◆ snd_pcm_hw_params_get_period_size_min()

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)

◆ snd_pcm_hw_params_get_period_time()

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 the configuration space does not contain a single value

Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

Examples: /test/latency.c.

◆ snd_pcm_hw_params_get_period_time_max()

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)

◆ snd_pcm_hw_params_get_period_time_min()

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)

◆ snd_pcm_hw_params_get_period_wakeup()

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

Extract period wakeup flag from a configuration space.

Parameters

pcm	PCM handle
params	Configuration space
val	0 = disabled, 1 = enabled period wakeups

Returns: Zero on success, otherwise a negative error code.

◆ snd_pcm_hw_params_get_periods()

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 the configuration space does not contain a single value

Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

◆ snd_pcm_hw_params_get_periods_max()

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)

◆ snd_pcm_hw_params_get_periods_min()

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)

Examples: /test/latency.c.

◆ snd_pcm_hw_params_get_rate()

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 the configuration space does not contain a single value

Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

◆ snd_pcm_hw_params_get_rate_max()

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)

◆ snd_pcm_hw_params_get_rate_min()

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)

◆ snd_pcm_hw_params_get_rate_resample()

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.

Parameters

pcm	PCM handle
params	Configuration space
val	0 = disable, 1 = enable rate resampling

Returns: 0 otherwise a negative error code

◆ snd_pcm_hw_params_get_subformat()

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 the configuration space does not contain a single value

◆ snd_pcm_hw_params_get_subformat_mask()

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

◆ snd_pcm_hw_params_get_tick_time()

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

(DEPRECATED) 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 the configuration space does not contain a single value

Actual exact value is <,=,> the approximate one following dir (-1, 0, 1)

◆ snd_pcm_hw_params_get_tick_time_max()

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

(DEPRECATED) 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)

◆ snd_pcm_hw_params_get_tick_time_min()

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

(DEPRECATED) 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)

◆ snd_pcm_hw_params_set_access()

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.

◆ snd_pcm_hw_params_set_access_first()

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

◆ snd_pcm_hw_params_set_access_last()

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
access	Returned last access type

Returns: 0 otherwise a negative error code

◆ snd_pcm_hw_params_set_access_mask()

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

◆ snd_pcm_hw_params_set_buffer_size()

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)

◆ snd_pcm_hw_params_set_buffer_size_first()

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

◆ snd_pcm_hw_params_set_buffer_size_last()

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

◆ snd_pcm_hw_params_set_buffer_size_max()

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)

Returns: 0 otherwise a negative error code if configuration space would become empty

◆ snd_pcm_hw_params_set_buffer_size_min()

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)

Returns: 0 otherwise a negative error code if configuration space would become empty

◆ snd_pcm_hw_params_set_buffer_size_minmax()

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)
max	approximate maximum buffer size in frames (on return filled with actual maximum)

Returns: 0 otherwise a negative error code if configuration space would become empty

◆ snd_pcm_hw_params_set_buffer_size_near()

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

Examples: /test/latency.c.

◆ snd_pcm_hw_params_set_buffer_time()

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)

◆ snd_pcm_hw_params_set_buffer_time_first()

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)

◆ snd_pcm_hw_params_set_buffer_time_last()

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)

◆ snd_pcm_hw_params_set_buffer_time_max()

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)

◆ snd_pcm_hw_params_set_buffer_time_min()

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)

◆ snd_pcm_hw_params_set_buffer_time_minmax()

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)

◆ snd_pcm_hw_params_set_buffer_time_near()

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
dir	Sub unit direction

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.

◆ snd_pcm_hw_params_set_channels()

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.

◆ snd_pcm_hw_params_set_channels_first()

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

◆ snd_pcm_hw_params_set_channels_last()

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

◆ snd_pcm_hw_params_set_channels_max()

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

◆ snd_pcm_hw_params_set_channels_min()

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

◆ snd_pcm_hw_params_set_channels_minmax()

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

◆ snd_pcm_hw_params_set_channels_near()

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

◆ snd_pcm_hw_params_set_drain_silence()

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

Restrict a configuration space to fill the end of playback stream with silence when drain() is invoked.

Parameters

pcm	PCM handle
params	Configuration space
val	0 = disabled, 1 = enabled (default) fill the end of the playback stream with silence when drain() is invoked

Returns: Zero on success, otherwise a negative error code.

When disabled, the application should handle the end of stream gracefully (fill the silent samples to align to the period size plus some extra samples for hardware / driver without perfect drain). Note that the rewind may be used for this purpose or the sw_params silencing mechanism.

◆ snd_pcm_hw_params_set_export_buffer()

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 to be accessible from outside.

Parameters

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

Returns: 0 otherwise a negative error code

◆ snd_pcm_hw_params_set_format()

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.

◆ snd_pcm_hw_params_set_format_first()

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

◆ snd_pcm_hw_params_set_format_last()

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

◆ snd_pcm_hw_params_set_format_mask()

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

◆ snd_pcm_hw_params_set_period_size()

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)

◆ snd_pcm_hw_params_set_period_size_first()

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)

◆ snd_pcm_hw_params_set_period_size_integer()

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

◆ snd_pcm_hw_params_set_period_size_last()

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)

◆ snd_pcm_hw_params_set_period_size_max()

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)

◆ snd_pcm_hw_params_set_period_size_min()

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)

◆ snd_pcm_hw_params_set_period_size_minmax()

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)

◆ snd_pcm_hw_params_set_period_size_near()

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
dir	Sub unit direction

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.

◆ snd_pcm_hw_params_set_period_time()

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)

◆ snd_pcm_hw_params_set_period_time_first()

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)

◆ snd_pcm_hw_params_set_period_time_last()

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
val	Returned maximum approximate period time
dir	Sub unit direction

Returns: approximate period duration in us

◆ snd_pcm_hw_params_set_period_time_max()

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)

◆ snd_pcm_hw_params_set_period_time_min()

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)

◆ snd_pcm_hw_params_set_period_time_minmax()

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)

◆ snd_pcm_hw_params_set_period_time_near()

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
dir	Sub unit direction

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.

◆ snd_pcm_hw_params_set_period_wakeup()

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

Restrict a configuration space to settings without period wakeups.

Parameters

pcm	PCM handle
params	Configuration space
val	0 = disable, 1 = enable (default) period wakeup

Returns: Zero on success, otherwise a negative error code.

This function must be called only on devices where non-blocking mode is enabled.

To check whether the hardware does support disabling period wakeups, call snd_pcm_hw_params_can_disable_period_wakeup(). If the hardware does not support this mode, standard period wakeups will be generated.

Even with disabled period wakeups, the period size/time/count parameters are valid; it is suggested to use snd_pcm_hw_params_set_period_size_last().

When period wakeups are disabled, the application must not use any functions that could block on this device. The use of poll should be limited to error cases. The application needs to use an external event or a timer to check the state of the ring buffer and refill it apropriately.

Examples: /test/latency.c.

◆ snd_pcm_hw_params_set_periods()

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)

◆ snd_pcm_hw_params_set_periods_first()

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)

◆ snd_pcm_hw_params_set_periods_integer()

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

◆ snd_pcm_hw_params_set_periods_last()

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)

◆ snd_pcm_hw_params_set_periods_max()

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)

◆ snd_pcm_hw_params_set_periods_min()

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)

◆ snd_pcm_hw_params_set_periods_minmax()

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)

◆ snd_pcm_hw_params_set_periods_near()

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
dir	Sub unit direction

Returns: 0 otherwise a negative error code if configuration space is empty

target/chosen exact value is <,=,> val following dir (-1,0,1)

◆ snd_pcm_hw_params_set_rate()

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)

◆ snd_pcm_hw_params_set_rate_first()

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)

◆ snd_pcm_hw_params_set_rate_last()

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)

◆ snd_pcm_hw_params_set_rate_max()

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)

◆ snd_pcm_hw_params_set_rate_min()

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)

◆ snd_pcm_hw_params_set_rate_minmax()

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)

◆ snd_pcm_hw_params_set_rate_near()

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
dir	Sub unit direction

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.

◆ snd_pcm_hw_params_set_rate_resample()

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.

Parameters

pcm	PCM handle
params	Configuration space
val	0 = disable, 1 = enable (default) rate resampling

Returns: 0 otherwise a negative error code

Examples: /test/latency.c, and /test/pcm.c.

◆ snd_pcm_hw_params_set_subformat()

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

◆ snd_pcm_hw_params_set_subformat_first()

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

◆ snd_pcm_hw_params_set_subformat_last()

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

◆ snd_pcm_hw_params_set_subformat_mask()

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

◆ snd_pcm_hw_params_set_tick_time()

int snd_pcm_hw_params_set_tick_time	(	snd_pcm_t *	pcm,
		snd_pcm_hw_params_t *	params,
		unsigned int	val,
		int	dir )

(DEPRECATED) 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)

◆ snd_pcm_hw_params_set_tick_time_first()

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

(DEPRECATED) 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)

◆ snd_pcm_hw_params_set_tick_time_last()

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

(DEPRECATED) 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)

◆ snd_pcm_hw_params_set_tick_time_max()

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

(DEPRECATED) 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)

◆ snd_pcm_hw_params_set_tick_time_min()

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

(DEPRECATED) 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)

◆ snd_pcm_hw_params_set_tick_time_minmax()

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 )

(DEPRECATED) 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)

◆ snd_pcm_hw_params_set_tick_time_near()

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

(DEPRECATED) 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
dir	Sub unit direction

Returns: 0 otherwise a negative error code if configuration space is empty

target/chosen exact value is <,=,> val following dir (-1,0,1)

◆ snd_pcm_hw_params_test_access()

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

◆ snd_pcm_hw_params_test_buffer_size()

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

Returns: 0 if available a negative error code otherwise

Wanted exact value is <,=,> val following dir (-1,0,1)

◆ snd_pcm_hw_params_test_buffer_time()

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)

◆ snd_pcm_hw_params_test_channels()

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

◆ snd_pcm_hw_params_test_format()

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

◆ snd_pcm_hw_params_test_period_size()

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)

◆ snd_pcm_hw_params_test_period_time()

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)

◆ snd_pcm_hw_params_test_periods()

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)

◆ snd_pcm_hw_params_test_rate()

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)

◆ snd_pcm_hw_params_test_subformat()

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

◆ snd_pcm_hw_params_test_tick_time()

int snd_pcm_hw_params_test_tick_time	(	snd_pcm_t *	pcm,
		snd_pcm_hw_params_t *	params,
		unsigned int	val,
		int	dir )

(DEPRECATED) 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)

◆ snd_pcm_sw_params_get_avail_min()

int snd_pcm_sw_params_get_avail_min	(	const snd_pcm_sw_params_t *	params,
		snd_pcm_uframes_t *	val )

Get avail min from a software configuration container.

Parameters

params	Software configuration container
val	returned minimum available frames to consider PCM ready

Returns: 0 otherwise a negative error code

This is a threshold value when the PCM stream is considered as ready for another read/write operation or poll event.

◆ snd_pcm_sw_params_get_period_event()

int snd_pcm_sw_params_get_period_event	(	const snd_pcm_sw_params_t *	params,
		int *	val )

Get period event from a software configuration container.

Parameters

params	Software configuration container
val	returned period event state

Returns: 0 otherwise a negative error code

◆ snd_pcm_sw_params_get_silence_size()

int snd_pcm_sw_params_get_silence_size	(	const snd_pcm_sw_params_t *	params,
		snd_pcm_uframes_t *	val )

Get silence size from a software configuration container.

Parameters

params	Software configuration container
val	Returned silence size in frames (0 for disabled)

Returns: 0 otherwise a negative error code

A portion of playback buffer is overwritten with silence when playback underrun is nearer than silence threshold (see snd_pcm_sw_params_set_silence_threshold)

◆ snd_pcm_sw_params_get_silence_threshold()

int snd_pcm_sw_params_get_silence_threshold	(	const snd_pcm_sw_params_t *	params,
		snd_pcm_uframes_t *	val )

Get silence threshold from a software configuration container.

Parameters

params	Software configuration container
val	Returned silence threshold in frames

Returns: 0 otherwise a negative error value

A portion of playback buffer is overwritten with silence (see snd_pcm_sw_params_set_silence_size) when playback underrun is nearer than silence threshold.

◆ snd_pcm_sw_params_get_sleep_min()

int snd_pcm_sw_params_get_sleep_min	(	const snd_pcm_sw_params_t *	params,
		unsigned int *	val )

(DEPRECATED) Get minimum numbers of ticks to sleep from a software configuration container

Parameters

params	Software configuration container
val	returned minimum number of ticks to sleep or 0 if tick timer is disabled

Returns: 0 otherwise a negative error code

◆ snd_pcm_sw_params_get_start_threshold()

int snd_pcm_sw_params_get_start_threshold	(	const snd_pcm_sw_params_t *	params,
		snd_pcm_uframes_t *	val )

Get start threshold from a software configuration container.

Parameters

params	Software configuration container
val	Returned start threshold in frames

Returns: 0 otherwise a negative error code

PCM is automatically started when playback frames available to PCM are >= threshold or when requested capture frames are >= threshold

◆ snd_pcm_sw_params_get_stop_threshold()

int snd_pcm_sw_params_get_stop_threshold	(	const snd_pcm_sw_params_t *	params,
		snd_pcm_uframes_t *	val )

Get stop threshold from a software configuration container.

Parameters

params	Software configuration container
val	Returned stop threshold in frames

Returns: 0 otherwise a negative error code

PCM is automatically stopped in SND_PCM_STATE_XRUN state when available frames is >= threshold. If the stop threshold is equal to boundary (also software parameter - sw_param) then automatic stop will be disabled (thus device will do the endless loop in the ring buffer).

◆ snd_pcm_sw_params_get_tstamp_mode()

int snd_pcm_sw_params_get_tstamp_mode	(	const snd_pcm_sw_params_t *	params,
		snd_pcm_tstamp_t *	val )

Get timestamp mode from a software configuration container.

Parameters

params	Software configuration container
val	Returned timestamp

Returns: 0 otherwise a negative error code

◆ snd_pcm_sw_params_get_tstamp_type()

int snd_pcm_sw_params_get_tstamp_type	(	const snd_pcm_sw_params_t *	params,
		snd_pcm_tstamp_type_t *	val )

Get timestamp type from a software configuration container.

Parameters

params	Software configuration container
val	Returned timestamp type

Returns: 0 otherwise a negative error code

◆ snd_pcm_sw_params_get_xfer_align()

int snd_pcm_sw_params_get_xfer_align	(	const snd_pcm_sw_params_t *	params,
		snd_pcm_uframes_t *	val )

(DEPRECATED) Get xfer align from a software configuration container

Parameters

params	Software configuration container
val	returned chunk size (frames are attempted to be transferred in chunks)

Returns: 0 otherwise a negative error code

◆ snd_pcm_sw_params_set_avail_min()

int snd_pcm_sw_params_set_avail_min	(	snd_pcm_t *	pcm,
		snd_pcm_sw_params_t *	params,
		snd_pcm_uframes_t	val )

Set avail min inside a software configuration container.

Parameters

pcm	PCM handle
params	Software configuration container
val	Minimum avail frames to consider PCM ready

Returns: 0 otherwise a negative error code

Note: This is similar to setting an OSS wakeup point. The valid values for 'val' are determined by the specific hardware. Most PC sound cards can only accept power of 2 frame counts (i.e. 512, 1024, 2048). You cannot use this as a high resolution timer - it is limited to how often the sound card hardware raises an interrupt.

Examples: /test/latency.c, and /test/pcm.c.

◆ snd_pcm_sw_params_set_period_event()

int snd_pcm_sw_params_set_period_event	(	snd_pcm_t *	pcm,
		snd_pcm_sw_params_t *	params,
		int	val )

Set period event inside a software configuration container.

Parameters

pcm	PCM handle
params	Software configuration container
val	0 = disable period event, 1 = enable period event

Returns: 0 otherwise a negative error code

An poll (select) wakeup event is raised if enabled.

Examples: /test/pcm.c.

◆ snd_pcm_sw_params_set_silence_size()

int snd_pcm_sw_params_set_silence_size	(	snd_pcm_t *	pcm,
		snd_pcm_sw_params_t *	params,
		snd_pcm_uframes_t	val )

Set silence size inside a software configuration container.

Parameters

pcm	PCM handle
params	Software configuration container
val	Silence size in frames (0 for disabled)

Returns: 0 otherwise a negative error code

A portion of playback buffer is overwritten with silence when playback underrun is nearer than silence threshold (see snd_pcm_sw_params_set_silence_threshold)

When drain silence (see snd_pcm_hw_params_get_drain_silence) is disabled, this will also apply for draining, i.e. silence is written also when the drain end is nearer than the silence threshold.

The special case is when silence size value is equal or greater than boundary. The unused portion of the ring buffer (initial written samples are untouched) is filled with silence at start. Later, only just processed sample area is filled with silence. Note: silence_threshold must be set to zero.

◆ snd_pcm_sw_params_set_silence_threshold()

int snd_pcm_sw_params_set_silence_threshold	(	snd_pcm_t *	pcm,
		snd_pcm_sw_params_t *	params,
		snd_pcm_uframes_t	val )

Set silence threshold inside a software configuration container.

Parameters

pcm	PCM handle
params	Software configuration container
val	Silence threshold in frames

Returns: 0 otherwise a negative error code

A portion of playback buffer is overwritten with silence (see snd_pcm_sw_params_set_silence_size) when playback underrun is nearer than silence threshold.

◆ snd_pcm_sw_params_set_sleep_min()

int snd_pcm_sw_params_set_sleep_min	(	snd_pcm_t *	pcm,
		snd_pcm_sw_params_t *	params,
		unsigned int	val )

(DEPRECATED) Set minimum number of ticks to sleep inside a software configuration container

Parameters

pcm	PCM handle
params	Software configuration container
val	Minimum ticks to sleep or 0 to disable the use of tick timer

Returns: 0 otherwise a negative error code

◆ snd_pcm_sw_params_set_start_threshold()

int snd_pcm_sw_params_set_start_threshold	(	snd_pcm_t *	pcm,
		snd_pcm_sw_params_t *	params,
		snd_pcm_uframes_t	val )

Set start threshold inside a software configuration container.

Parameters

pcm	PCM handle
params	Software configuration container
val	Start threshold in frames

Returns: 0 otherwise a negative error code

PCM is automatically started when playback frames available to PCM are >= threshold or when requested capture frames are >= threshold

Examples: /test/latency.c, and /test/pcm.c.

◆ snd_pcm_sw_params_set_stop_threshold()

int snd_pcm_sw_params_set_stop_threshold	(	snd_pcm_t *	pcm,
		snd_pcm_sw_params_t *	params,
		snd_pcm_uframes_t	val )

Set stop threshold inside a software configuration container.

Parameters

pcm	PCM handle
params	Software configuration container
val	Stop threshold in frames

Returns: 0 otherwise a negative error code

PCM is automatically stopped in SND_PCM_STATE_XRUN state when available frames is >= threshold. If the stop threshold is equal to boundary (also software parameter - sw_param) then automatic stop will be disabled (thus device will do the endless loop in the ring buffer).

◆ snd_pcm_sw_params_set_tstamp_mode()

int snd_pcm_sw_params_set_tstamp_mode	(	snd_pcm_t *	pcm,
		snd_pcm_sw_params_t *	params,
		snd_pcm_tstamp_t	val )

Set timestamp mode inside a software configuration container.

Parameters

pcm	PCM handle
params	Software configuration container
val	Timestamp mode

Returns: 0 otherwise a negative error code

◆ snd_pcm_sw_params_set_tstamp_type()

int snd_pcm_sw_params_set_tstamp_type	(	snd_pcm_t *	pcm,
		snd_pcm_sw_params_t *	params,
		snd_pcm_tstamp_type_t	val )

Set timestamp type inside a software configuration container.

Parameters

pcm	PCM handle
params	Software configuration container
val	Timestamp type

Returns: 0 otherwise a negative error code

◆ snd_pcm_sw_params_set_xfer_align()

int snd_pcm_sw_params_set_xfer_align	(	snd_pcm_t *	pcm,
		snd_pcm_sw_params_t *	params,
		snd_pcm_uframes_t	val )

(DEPRECATED) Set xfer align inside a software configuration container

Parameters

pcm	PCM handle
params	Software configuration container
val	Chunk size (frames are attempted to be transferred in chunks)

Returns: 0 otherwise a negative error code

◆ snd_pcm_tstamp_type_name()

const char * snd_pcm_tstamp_type_name ( snd_pcm_tstamp_type_t type )

get name of PCM tstamp type setting

Parameters

type	PCM tstamp type

Returns: ascii name of PCM tstamp type setting

Functions

Detailed Description

Function Documentation

◆ snd_pcm_hw_params_get_access()

◆ snd_pcm_hw_params_get_access_mask()

◆ snd_pcm_hw_params_get_buffer_size()

◆ snd_pcm_hw_params_get_buffer_size_max()

◆ snd_pcm_hw_params_get_buffer_size_min()

◆ snd_pcm_hw_params_get_buffer_time()

◆ snd_pcm_hw_params_get_buffer_time_max()

◆ snd_pcm_hw_params_get_buffer_time_min()

◆ snd_pcm_hw_params_get_channels()

◆ snd_pcm_hw_params_get_channels_max()

◆ snd_pcm_hw_params_get_channels_min()

◆ snd_pcm_hw_params_get_drain_silence()

◆ snd_pcm_hw_params_get_export_buffer()

◆ snd_pcm_hw_params_get_format()

◆ snd_pcm_hw_params_get_format_mask()

◆ snd_pcm_hw_params_get_period_size()

◆ snd_pcm_hw_params_get_period_size_max()

◆ snd_pcm_hw_params_get_period_size_min()

◆ snd_pcm_hw_params_get_period_time()

◆ snd_pcm_hw_params_get_period_time_max()

◆ snd_pcm_hw_params_get_period_time_min()

◆ snd_pcm_hw_params_get_period_wakeup()

◆ snd_pcm_hw_params_get_periods()

◆ snd_pcm_hw_params_get_periods_max()

◆ snd_pcm_hw_params_get_periods_min()

◆ snd_pcm_hw_params_get_rate()

◆ snd_pcm_hw_params_get_rate_max()

◆ snd_pcm_hw_params_get_rate_min()

◆ snd_pcm_hw_params_get_rate_resample()

◆ snd_pcm_hw_params_get_subformat()

◆ snd_pcm_hw_params_get_subformat_mask()

◆ snd_pcm_hw_params_get_tick_time()

◆ snd_pcm_hw_params_get_tick_time_max()

◆ snd_pcm_hw_params_get_tick_time_min()

◆ snd_pcm_hw_params_set_access()

◆ snd_pcm_hw_params_set_access_first()

◆ snd_pcm_hw_params_set_access_last()

◆ snd_pcm_hw_params_set_access_mask()

◆ snd_pcm_hw_params_set_buffer_size()

◆ snd_pcm_hw_params_set_buffer_size_first()

◆ snd_pcm_hw_params_set_buffer_size_last()

◆ snd_pcm_hw_params_set_buffer_size_max()

◆ snd_pcm_hw_params_set_buffer_size_min()

◆ snd_pcm_hw_params_set_buffer_size_minmax()

◆ snd_pcm_hw_params_set_buffer_size_near()

◆ snd_pcm_hw_params_set_buffer_time()

◆ snd_pcm_hw_params_set_buffer_time_first()

◆ snd_pcm_hw_params_set_buffer_time_last()

◆ snd_pcm_hw_params_set_buffer_time_max()

◆ snd_pcm_hw_params_set_buffer_time_min()

◆ snd_pcm_hw_params_set_buffer_time_minmax()

◆ snd_pcm_hw_params_set_buffer_time_near()

◆ snd_pcm_hw_params_set_channels()

◆ snd_pcm_hw_params_set_channels_first()

◆ snd_pcm_hw_params_set_channels_last()

◆ snd_pcm_hw_params_set_channels_max()

◆ snd_pcm_hw_params_set_channels_min()

◆ snd_pcm_hw_params_set_channels_minmax()

◆ snd_pcm_hw_params_set_channels_near()

◆ snd_pcm_hw_params_set_drain_silence()

◆ snd_pcm_hw_params_set_export_buffer()

◆ snd_pcm_hw_params_set_format()

◆ snd_pcm_hw_params_set_format_first()

◆ snd_pcm_hw_params_set_format_last()

◆ snd_pcm_hw_params_set_format_mask()

◆ snd_pcm_hw_params_set_period_size()

◆ snd_pcm_hw_params_set_period_size_first()

◆ snd_pcm_hw_params_set_period_size_integer()

◆ snd_pcm_hw_params_set_period_size_last()

◆ snd_pcm_hw_params_set_period_size_max()

◆ snd_pcm_hw_params_set_period_size_min()

◆ snd_pcm_hw_params_set_period_size_minmax()

◆ snd_pcm_hw_params_set_period_size_near()

◆ snd_pcm_hw_params_set_period_time()

◆ snd_pcm_hw_params_set_period_time_first()

◆ snd_pcm_hw_params_set_period_time_last()

◆ snd_pcm_hw_params_set_period_time_max()