pa_linux_alsa.c File Reference

#include <alsa/asoundlib.h>
#include <sys/poll.h>
#include <string.h>
#include <limits.h>
#include <math.h>
#include <pthread.h>
#include <signal.h>
#include <time.h>
#include <sys/mman.h>
#include "portaudio.h"
#include "pa_util.h"
#include "pa_unix_util.h"
#include "pa_allocation.h"
#include "pa_hostapi.h"
#include "pa_stream.h"
#include "pa_cpuload.h"
#include "pa_process.h"
#include "pa_endianness.h"
#include "pa_debugprint.h"
#include "pa_linux_alsa.h"

Data Structures
struct	PaAlsaStreamComponent
struct	PaAlsaStream
struct	PaAlsaHostApiRepresentation
struct	PaAlsaDeviceInfo
struct	HwDevInfo

Macros
#define	ALSA_PCM_NEW_HW_PARAMS_API
#define	ALSA_PCM_NEW_SW_PARAMS_API
#define	SND_PCM_TSTAMP_ENABLE   SND_PCM_TSTAMP_MMAP
#define	ALSA_VERSION_INT(major, minor, subminor)   ((major << 16) | (minor << 8) | subminor)
#define	RATE_MAX_DEVIATE_RATIO   100
#define	_PA_DEFINE_FUNC(x)   typedef typeof(x) x##_ft; static x##_ft *alsa_##x = 0
#define	__alsa_snd_alloca(ptr, type)   do { size_t __alsa_alloca_size = alsa_##type##_sizeof(); (*ptr) = (type##_t *) alloca(__alsa_alloca_size); memset(*ptr, 0, __alsa_alloca_size); } while (0)
#define	alsa_snd_pcm_hw_params_alloca(ptr)   __alsa_snd_alloca(ptr, snd_pcm_hw_params)
#define	alsa_snd_pcm_sw_params_alloca(ptr)   __alsa_snd_alloca(ptr, snd_pcm_sw_params)
#define	alsa_snd_pcm_info_alloca(ptr)   __alsa_snd_alloca(ptr, snd_pcm_info)
#define	alsa_snd_ctl_card_info_alloca(ptr)   __alsa_snd_alloca(ptr, snd_ctl_card_info)
#define	alsa_snd_pcm_status_alloca(ptr)   __alsa_snd_alloca(ptr, snd_pcm_status)
#define	alsa_snd_config_for_each(pos, next, node)
#define	PA_ALSA_PATHNAME   "libasound.so"
#define	_PA_LOAD_FUNC(x)   alsa_##x = &x
#define	ENSURE_(expr, code)
#define	ASSERT_CALL_(expr, success)

Typedefs
typedef struct PaAlsaStream	PaAlsaStream
typedef struct PaAlsaHostApiRepresentation	PaAlsaHostApiRepresentation
typedef struct PaAlsaDeviceInfo	PaAlsaDeviceInfo

Enumerations
enum	StreamDirection { StreamDirection_In, StreamDirection_Out }

Functions
	_PA_DEFINE_FUNC (snd_pcm_open)
	_PA_DEFINE_FUNC (snd_pcm_close)
	_PA_DEFINE_FUNC (snd_pcm_nonblock)
	_PA_DEFINE_FUNC (snd_pcm_frames_to_bytes)
	_PA_DEFINE_FUNC (snd_pcm_prepare)
	_PA_DEFINE_FUNC (snd_pcm_start)
	_PA_DEFINE_FUNC (snd_pcm_resume)
	_PA_DEFINE_FUNC (snd_pcm_wait)
	_PA_DEFINE_FUNC (snd_pcm_state)
	_PA_DEFINE_FUNC (snd_pcm_avail_update)
	_PA_DEFINE_FUNC (snd_pcm_areas_silence)
	_PA_DEFINE_FUNC (snd_pcm_mmap_begin)
	_PA_DEFINE_FUNC (snd_pcm_mmap_commit)
	_PA_DEFINE_FUNC (snd_pcm_readi)
	_PA_DEFINE_FUNC (snd_pcm_readn)
	_PA_DEFINE_FUNC (snd_pcm_writei)
	_PA_DEFINE_FUNC (snd_pcm_writen)
	_PA_DEFINE_FUNC (snd_pcm_drain)
	_PA_DEFINE_FUNC (snd_pcm_recover)
	_PA_DEFINE_FUNC (snd_pcm_drop)
	_PA_DEFINE_FUNC (snd_pcm_area_copy)
	_PA_DEFINE_FUNC (snd_pcm_poll_descriptors)
	_PA_DEFINE_FUNC (snd_pcm_poll_descriptors_count)
	_PA_DEFINE_FUNC (snd_pcm_poll_descriptors_revents)
	_PA_DEFINE_FUNC (snd_pcm_format_size)
	_PA_DEFINE_FUNC (snd_pcm_link)
	_PA_DEFINE_FUNC (snd_pcm_delay)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_sizeof)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_malloc)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_free)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_any)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_access)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_format)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_channels)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_rate_near)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_rate)
	!! More...
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_rate_resample)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_buffer_size)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_buffer_size_near)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_buffer_size_min)
	!! More...
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_period_size_near)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_periods_integer)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_periods_min)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_get_buffer_size)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_get_channels_min)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_get_channels_max)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_test_period_size)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_test_format)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_test_access)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_dump)
	_PA_DEFINE_FUNC (snd_pcm_hw_params)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_get_periods_min)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_get_periods_max)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_set_period_size)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_get_period_size_min)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_get_period_size_max)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_get_buffer_size_max)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_get_rate_min)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_get_rate_max)
	_PA_DEFINE_FUNC (snd_pcm_hw_params_get_rate_numden)
	_PA_DEFINE_FUNC (snd_pcm_sw_params_sizeof)
	_PA_DEFINE_FUNC (snd_pcm_sw_params_malloc)
	_PA_DEFINE_FUNC (snd_pcm_sw_params_current)
	_PA_DEFINE_FUNC (snd_pcm_sw_params_set_avail_min)
	_PA_DEFINE_FUNC (snd_pcm_sw_params)
	_PA_DEFINE_FUNC (snd_pcm_sw_params_free)
	_PA_DEFINE_FUNC (snd_pcm_sw_params_set_start_threshold)
	_PA_DEFINE_FUNC (snd_pcm_sw_params_set_stop_threshold)
	_PA_DEFINE_FUNC (snd_pcm_sw_params_get_boundary)
	_PA_DEFINE_FUNC (snd_pcm_sw_params_set_silence_threshold)
	_PA_DEFINE_FUNC (snd_pcm_sw_params_set_silence_size)
	_PA_DEFINE_FUNC (snd_pcm_sw_params_set_xfer_align)
	_PA_DEFINE_FUNC (snd_pcm_sw_params_set_tstamp_mode)
	_PA_DEFINE_FUNC (snd_pcm_info)
	_PA_DEFINE_FUNC (snd_pcm_info_sizeof)
	_PA_DEFINE_FUNC (snd_pcm_info_malloc)
	_PA_DEFINE_FUNC (snd_pcm_info_free)
	_PA_DEFINE_FUNC (snd_pcm_info_set_device)
	_PA_DEFINE_FUNC (snd_pcm_info_set_subdevice)
	_PA_DEFINE_FUNC (snd_pcm_info_set_stream)
	_PA_DEFINE_FUNC (snd_pcm_info_get_name)
	_PA_DEFINE_FUNC (snd_pcm_info_get_card)
	_PA_DEFINE_FUNC (snd_ctl_pcm_next_device)
	_PA_DEFINE_FUNC (snd_ctl_pcm_info)
	_PA_DEFINE_FUNC (snd_ctl_open)
	_PA_DEFINE_FUNC (snd_ctl_close)
	_PA_DEFINE_FUNC (snd_ctl_card_info_malloc)
	_PA_DEFINE_FUNC (snd_ctl_card_info_free)
	_PA_DEFINE_FUNC (snd_ctl_card_info)
	_PA_DEFINE_FUNC (snd_ctl_card_info_sizeof)
	_PA_DEFINE_FUNC (snd_ctl_card_info_get_name)
	_PA_DEFINE_FUNC (snd_config)
	_PA_DEFINE_FUNC (snd_config_update)
	_PA_DEFINE_FUNC (snd_config_search)
	_PA_DEFINE_FUNC (snd_config_iterator_entry)
	_PA_DEFINE_FUNC (snd_config_iterator_first)
	_PA_DEFINE_FUNC (snd_config_iterator_end)
	_PA_DEFINE_FUNC (snd_config_iterator_next)
	_PA_DEFINE_FUNC (snd_config_get_string)
	_PA_DEFINE_FUNC (snd_config_get_id)
	_PA_DEFINE_FUNC (snd_config_update_free_global)
	_PA_DEFINE_FUNC (snd_pcm_status)
	_PA_DEFINE_FUNC (snd_pcm_status_sizeof)
	_PA_DEFINE_FUNC (snd_pcm_status_get_tstamp)
	_PA_DEFINE_FUNC (snd_pcm_status_get_state)
	_PA_DEFINE_FUNC (snd_pcm_status_get_trigger_tstamp)
	_PA_DEFINE_FUNC (snd_pcm_status_get_delay)
	_PA_DEFINE_FUNC (snd_card_next)
	_PA_DEFINE_FUNC (snd_asoundlib_version)
	_PA_DEFINE_FUNC (snd_strerror)
	_PA_DEFINE_FUNC (snd_output_stdio_attach)
void	PaAlsa_SetLibraryPathName (const char *pathName)
int	PaAlsa_SetNumPeriods (int numPeriods)
PaError	PaAlsa_Initialize (PaUtilHostApiRepresentation **hostApi, PaHostApiIndex hostApiIndex)
void	PaAlsa_InitializeStreamInfo (PaAlsaStreamInfo *info)
void	PaAlsa_EnableRealtimeScheduling (PaStream *s, int enable)
PaError	PaAlsa_GetStreamInputCard (PaStream *s, int *card)
PaError	PaAlsa_GetStreamOutputCard (PaStream *s, int *card)
PaError	PaAlsa_SetRetriesBusy (int retries)

Variables
HwDevInfo	predefinedNames []

Macro Definition Documentation

#define __alsa_snd_alloca	(		ptr,
			type
	)		do { size_t __alsa_alloca_size = alsa_##type##_sizeof(); (*ptr) = (type##_t *) alloca(__alsa_alloca_size); memset(*ptr, 0, __alsa_alloca_size); } while (0)

#define _PA_DEFINE_FUNC

(

x

)

typedef typeof(x) x##_ft; static x##_ft *alsa_##x = 0

#define _PA_LOAD_FUNC

(

x

)

alsa_##x = &x

#define ALSA_PCM_NEW_HW_PARAMS_API

#define ALSA_PCM_NEW_SW_PARAMS_API

#define alsa_snd_config_for_each	(		pos,
			next,
			node
	)

Value:

for (pos = alsa_snd_config_iterator_first(node),\
         next = alsa_snd_config_iterator_next(pos);\
         pos != alsa_snd_config_iterator_end(node); pos = next, next = alsa_snd_config_iterator_next(pos))

#define alsa_snd_ctl_card_info_alloca

(

ptr

)

__alsa_snd_alloca(ptr, snd_ctl_card_info)

#define alsa_snd_pcm_hw_params_alloca

(

ptr

)

__alsa_snd_alloca(ptr, snd_pcm_hw_params)

#define alsa_snd_pcm_info_alloca

(

ptr

)

__alsa_snd_alloca(ptr, snd_pcm_info)

Referenced by PaAlsa_GetStreamInputCard(), and PaAlsa_GetStreamOutputCard().

#define alsa_snd_pcm_status_alloca

(

ptr

)

__alsa_snd_alloca(ptr, snd_pcm_status)

#define alsa_snd_pcm_sw_params_alloca

(

ptr

)

__alsa_snd_alloca(ptr, snd_pcm_sw_params)

#define ALSA_VERSION_INT	(		major,
			minor,
			subminor
	)		((major << 16) | (minor << 8) | subminor)

#define ASSERT_CALL_	(		expr,
			success
	)

Value:

do {\
        int __pa_assert_error_id;\
        __pa_assert_error_id = (expr);\
        assert( success == __pa_assert_error_id );\
    } while (0)

#define ENSURE_	(		expr,
			code
	)

Value:

do { \
        int __pa_unsure_error_id;\
        if( UNLIKELY( (__pa_unsure_error_id = (expr)) < 0 ) ) \
        { \
            /* PaUtil_SetLastHostErrorInfo should only be used in the main thread */ \
            if( (code) == paUnanticipatedHostError && pthread_equal( pthread_self(), paUnixMainThread) ) \
            { \
                PaUtil_SetLastHostErrorInfo( paALSA, __pa_unsure_error_id, alsa_snd_strerror( __pa_unsure_error_id ) ); \
            } \
            PaUtil_DebugPrint( "Expression '" #expr "' failed in '" __FILE__ "', line: " STRINGIZE( __LINE__ ) "\n" ); \
            if( (code) == paUnanticipatedHostError ) \
                PA_DEBUG(( "Host error description: %s\n", alsa_snd_strerror( __pa_unsure_error_id ) )); \
            result = (code); \
            goto error; \
        } \
    } while (0)

#define PA_ALSA_PATHNAME   "libasound.so"

#define RATE_MAX_DEVIATE_RATIO   100

#define SND_PCM_TSTAMP_ENABLE   SND_PCM_TSTAMP_MMAP

Typedef Documentation

typedef struct PaAlsaDeviceInfo PaAlsaDeviceInfo

typedef struct PaAlsaHostApiRepresentation PaAlsaHostApiRepresentation

typedef struct PaAlsaStream PaAlsaStream

Enumeration Type Documentation

enum StreamDirection

Enumerator
StreamDirection_In
StreamDirection_Out

Function Documentation

_PA_DEFINE_FUNC

(

snd_pcm_open

)

_PA_DEFINE_FUNC

(

snd_pcm_close

)

_PA_DEFINE_FUNC

(

snd_pcm_nonblock

)

_PA_DEFINE_FUNC

(

snd_pcm_frames_to_bytes

)

_PA_DEFINE_FUNC

(

snd_pcm_prepare

)

_PA_DEFINE_FUNC

(

snd_pcm_start

)

_PA_DEFINE_FUNC

(

snd_pcm_resume

)

_PA_DEFINE_FUNC

(

snd_pcm_wait

)

_PA_DEFINE_FUNC

(

snd_pcm_state

)

_PA_DEFINE_FUNC

(

snd_pcm_avail_update

)

_PA_DEFINE_FUNC

(

snd_pcm_areas_silence

)

_PA_DEFINE_FUNC

(

snd_pcm_mmap_begin

)

_PA_DEFINE_FUNC

(

snd_pcm_mmap_commit

)

_PA_DEFINE_FUNC

(

snd_pcm_readi

)

_PA_DEFINE_FUNC

(

snd_pcm_readn

)

_PA_DEFINE_FUNC

(

snd_pcm_writei

)

_PA_DEFINE_FUNC

(

snd_pcm_writen

)

_PA_DEFINE_FUNC

(

snd_pcm_drain

)

_PA_DEFINE_FUNC

(

snd_pcm_recover

)

_PA_DEFINE_FUNC

(

snd_pcm_drop

)

_PA_DEFINE_FUNC

(

snd_pcm_area_copy

)

_PA_DEFINE_FUNC

(

snd_pcm_poll_descriptors

)

_PA_DEFINE_FUNC

(

snd_pcm_poll_descriptors_count

)

_PA_DEFINE_FUNC

(

snd_pcm_poll_descriptors_revents

)

_PA_DEFINE_FUNC

(

snd_pcm_format_size

)

_PA_DEFINE_FUNC

(

snd_pcm_link

)

_PA_DEFINE_FUNC

(

snd_pcm_delay

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_sizeof

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_malloc

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_free

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_any

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_access

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_format

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_channels

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_rate_near

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_rate

)

!!

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_rate_resample

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_buffer_size

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_buffer_size_near

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_buffer_size_min

)

!!

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_period_size_near

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_periods_integer

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_periods_min

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_get_buffer_size

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_get_channels_min

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_get_channels_max

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_test_period_size

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_test_format

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_test_access

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_dump

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_get_periods_min

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_get_periods_max

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_set_period_size

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_get_period_size_min

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_get_period_size_max

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_get_buffer_size_max

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_get_rate_min

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_get_rate_max

)

_PA_DEFINE_FUNC

(

snd_pcm_hw_params_get_rate_numden

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params_sizeof

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params_malloc

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params_current

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params_set_avail_min

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params_free

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params_set_start_threshold

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params_set_stop_threshold

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params_get_boundary

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params_set_silence_threshold

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params_set_silence_size

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params_set_xfer_align

)

_PA_DEFINE_FUNC

(

snd_pcm_sw_params_set_tstamp_mode

)

_PA_DEFINE_FUNC

(

snd_pcm_info

)

_PA_DEFINE_FUNC

(

snd_pcm_info_sizeof

)

_PA_DEFINE_FUNC

(

snd_pcm_info_malloc

)

_PA_DEFINE_FUNC

(

snd_pcm_info_free

)

_PA_DEFINE_FUNC

(

snd_pcm_info_set_device

)

_PA_DEFINE_FUNC

(

snd_pcm_info_set_subdevice

)

_PA_DEFINE_FUNC

(

snd_pcm_info_set_stream

)

_PA_DEFINE_FUNC

(

snd_pcm_info_get_name

)

_PA_DEFINE_FUNC

(

snd_pcm_info_get_card

)

_PA_DEFINE_FUNC

(

snd_ctl_pcm_next_device

)

_PA_DEFINE_FUNC

(

snd_ctl_pcm_info

)

_PA_DEFINE_FUNC

(

snd_ctl_open

)

_PA_DEFINE_FUNC

(

snd_ctl_close

)

_PA_DEFINE_FUNC

(

snd_ctl_card_info_malloc

)

_PA_DEFINE_FUNC

(

snd_ctl_card_info_free

)

_PA_DEFINE_FUNC

(

snd_ctl_card_info

)

_PA_DEFINE_FUNC

(

snd_ctl_card_info_sizeof

)

_PA_DEFINE_FUNC

(

snd_ctl_card_info_get_name

)

_PA_DEFINE_FUNC

(

snd_config

)

_PA_DEFINE_FUNC

(

snd_config_update

)

_PA_DEFINE_FUNC

(

snd_config_search

)

_PA_DEFINE_FUNC

(

snd_config_iterator_entry

)

_PA_DEFINE_FUNC

(

snd_config_iterator_first

)

_PA_DEFINE_FUNC

(

snd_config_iterator_end

)

_PA_DEFINE_FUNC

(

snd_config_iterator_next

)

_PA_DEFINE_FUNC

(

snd_config_get_string

)

_PA_DEFINE_FUNC

(

snd_config_get_id

)

_PA_DEFINE_FUNC

(

snd_config_update_free_global

)

_PA_DEFINE_FUNC

(

snd_pcm_status

)

_PA_DEFINE_FUNC

(

snd_pcm_status_sizeof

)

_PA_DEFINE_FUNC

(

snd_pcm_status_get_tstamp

)

_PA_DEFINE_FUNC

(

snd_pcm_status_get_state

)

_PA_DEFINE_FUNC

(

snd_pcm_status_get_trigger_tstamp

)

_PA_DEFINE_FUNC

(

snd_pcm_status_get_delay

)

_PA_DEFINE_FUNC

(

snd_card_next

)

_PA_DEFINE_FUNC

(

snd_asoundlib_version

)

_PA_DEFINE_FUNC

(

snd_strerror

)

_PA_DEFINE_FUNC

(

snd_output_stdio_attach

)

void PaAlsa_EnableRealtimeScheduling	(	PaStream *	s,
		int	enable
	)

Instruct whether to enable real-time priority when starting the audio thread.

If this is turned on by the stream is started, the audio callback thread will be created with the FIFO scheduling policy, which is suitable for realtime operation.

References PaAlsaStream::rtSched.

PaError PaAlsa_GetStreamInputCard	(	PaStream *	s,
		int *	card
	)

Get the ALSA-lib card index of this stream's input device.

References alsa_snd_pcm_info_alloca, PaAlsaStream::capture, PA_ENSURE, PA_UNLESS, paDeviceUnavailable, paNoError, and PaAlsaStreamComponent::pcm.

PaError PaAlsa_GetStreamOutputCard	(	PaStream *	s,
		int *	card
	)

Get the ALSA-lib card index of this stream's output device.

References alsa_snd_pcm_info_alloca, PA_ENSURE, PA_UNLESS, paDeviceUnavailable, paNoError, PaAlsaStreamComponent::pcm, and PaAlsaStream::playback.

PaError PaAlsa_Initialize	(	PaUtilHostApiRepresentation **	hostApi,
		PaHostApiIndex	hostApiIndex
	)

Uncommented because AlsaErrorHandler is unused for anything good yet. If AlsaErrorHandler is to be used, do not forget to register this callback in PaAlsa_Initialize, and unregister in Terminate.

If AlsaErrorHandler is to be used, do not forget to unregister callback pointer in Terminate function.

References PaAlsaHostApiRepresentation::allocations, PaAlsaHostApiRepresentation::alsaLibVersion, PaAlsaHostApiRepresentation::blockingStreamInterface, PaAlsaHostApiRepresentation::callbackStreamInterface, PaAlsaHostApiRepresentation::hostApiIndex, PA_ENSURE, PA_UNLESS, paALSA, paHostApiNotFound, paInsufficientMemory, paNoError, PaUnixThreading_Initialize(), PaUtil_AllocateMemory(), PaUtil_CreateAllocationGroup(), PaUtil_DestroyAllocationGroup(), PaUtil_DummyGetCpuLoad(), PaUtil_DummyGetReadAvailable(), PaUtil_DummyGetWriteAvailable(), PaUtil_DummyRead(), PaUtil_DummyWrite(), PaUtil_FreeAllAllocations(), PaUtil_FreeMemory(), and PaUtil_InitializeStreamInterface().

void PaAlsa_InitializeStreamInfo

(

PaAlsaStreamInfo *

info

)

Initialize host API specific structure, call this before setting relevant attributes.

References PaAlsaStreamInfo::deviceString, PaAlsaStreamInfo::hostApiType, paALSA, PaAlsaStreamInfo::size, and PaAlsaStreamInfo::version.

void PaAlsa_SetLibraryPathName

(

const char *

pathName

)

Set the path and name of ALSA library file if PortAudio is configured to load it dynamically (see PA_ALSA_DYNAMIC). This setting will overwrite the default name set by PA_ALSA_PATHNAME define.

Parameters

pathName

Full path with filename. Only filename can be used, but dlopen() will lookup default searchable directories (/usr/lib;/usr/local/lib) then.

int PaAlsa_SetNumPeriods

(

int

numPeriods

)

Set the number of periods (buffer fragments) to configure devices with.

By default the number of periods is 4, this is the lowest number of periods that works well on the author's soundcard.

Parameters

numPeriods

The number of periods.

References paNoError.

PaError PaAlsa_SetRetriesBusy

(

int

retries

)

Set the maximum number of times to retry opening busy device (sleeping for a short interval inbetween).

References paNoError.

Variable Documentation

HwDevInfo predefinedNames[]