External I/O plugin SDK
[External PCM plugin SDK]

Data Structures

struct  snd_pcm_ioplug_t
struct  snd_pcm_ioplug_callback_t

Defines

#define SND_PCM_IOPLUG_FLAG_LISTED   (1<<0)
#define SND_PCM_IOPLUG_FLAG_MONOTONIC   (1<<1)
#define SND_PCM_IOPLUG_VERSION_MAJOR   1
#define SND_PCM_IOPLUG_VERSION_MINOR   0
#define SND_PCM_IOPLUG_VERSION_TINY   1
#define SND_PCM_IOPLUG_VERSION

Enumerations

enum  {
  SND_PCM_IOPLUG_HW_ACCESS = 0, SND_PCM_IOPLUG_HW_FORMAT, SND_PCM_IOPLUG_HW_CHANNELS, SND_PCM_IOPLUG_HW_RATE,
  SND_PCM_IOPLUG_HW_PERIOD_BYTES, SND_PCM_IOPLUG_HW_BUFFER_BYTES, SND_PCM_IOPLUG_HW_PERIODS, SND_PCM_IOPLUG_HW_PARAMS
}

Functions

int snd_pcm_ioplug_create (snd_pcm_ioplug_t *io, const char *name, snd_pcm_stream_t stream, int mode)
 Create an ioplug instance.
int snd_pcm_ioplug_delete (snd_pcm_ioplug_t *io)
 Delete the ioplug instance.
int snd_pcm_ioplug_reinit_status (snd_pcm_ioplug_t *ioplug)
 Reinitialize the poll and mmap status.
const snd_pcm_channel_area_tsnd_pcm_ioplug_mmap_areas (snd_pcm_ioplug_t *ioplug)
 Get mmap area of ioplug.
void snd_pcm_ioplug_params_reset (snd_pcm_ioplug_t *io)
 Reset ioplug parameters.
int snd_pcm_ioplug_set_param_minmax (snd_pcm_ioplug_t *io, int type, unsigned int min, unsigned int max)
 Set parameter as the min/max values.
int snd_pcm_ioplug_set_param_list (snd_pcm_ioplug_t *io, int type, unsigned int num_list, const unsigned int *list)
 Set parameter as the list.
int snd_pcm_ioplug_set_state (snd_pcm_ioplug_t *ioplug, snd_pcm_state_t state)
 Change the ioplug PCM status.

Detailed Description

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


Define Documentation

#define SND_PCM_IOPLUG_FLAG_LISTED   (1<<0)

list up this PCM

#define SND_PCM_IOPLUG_FLAG_MONOTONIC   (1<<1)

monotonic timestamps

#define SND_PCM_IOPLUG_VERSION
Value:

IO-plugin protocol version

#define SND_PCM_IOPLUG_VERSION_MAJOR   1

Protocol major version

#define SND_PCM_IOPLUG_VERSION_MINOR   0

Protocol minor version

#define SND_PCM_IOPLUG_VERSION_TINY   1

Protocol tiny version


Enumeration Type Documentation

anonymous enum

hw constraints for ioplug

Enumerator:
SND_PCM_IOPLUG_HW_ACCESS 

access type

SND_PCM_IOPLUG_HW_FORMAT 

format

SND_PCM_IOPLUG_HW_CHANNELS 

channels

SND_PCM_IOPLUG_HW_RATE 

rate

SND_PCM_IOPLUG_HW_PERIOD_BYTES 

period bytes

SND_PCM_IOPLUG_HW_BUFFER_BYTES 

buffer bytes

SND_PCM_IOPLUG_HW_PERIODS 

number of periods

SND_PCM_IOPLUG_HW_PARAMS 

max number of hw constraints


Function Documentation

int snd_pcm_ioplug_create ( snd_pcm_ioplug_t *  ioplug,
const char *  name,
snd_pcm_stream_t  stream,
int  mode 
)

Create an ioplug instance.

Parameters:
ioplug the ioplug handle
name name of PCM
stream stream direction
mode PCM open mode
Returns:
0 if successful, or a negative error code

Creates the ioplug instance.

The callback is the mandatory field of ioplug handle. At least, start, stop and pointer callbacks must be set before calling this function.

int snd_pcm_ioplug_delete ( snd_pcm_ioplug_t *  ioplug  ) 

Delete the ioplug instance.

Parameters:
ioplug the ioplug handle
Returns:
0 if successful, or a negative error code
const snd_pcm_channel_area_t* snd_pcm_ioplug_mmap_areas ( snd_pcm_ioplug_t *  ioplug  ) 

Get mmap area of ioplug.

Parameters:
ioplug the ioplug handle
Returns:
the mmap channel areas if available, or NULL

Returns the mmap channel areas if available. When mmap_rw field is not set, this function always returns NULL.

void snd_pcm_ioplug_params_reset ( snd_pcm_ioplug_t *  ioplug  ) 

Reset ioplug parameters.

Parameters:
ioplug the ioplug handle

Resets the all parameters for the given ioplug handle.

int snd_pcm_ioplug_reinit_status ( snd_pcm_ioplug_t *  ioplug  ) 

Reinitialize the poll and mmap status.

Parameters:
ioplug the ioplug handle
Returns:
0 if successful, or a negative error code

Reinitializes the poll and the mmap status of the PCM. Call this function to propagate the status change in the ioplug instance to its PCM internals.

int snd_pcm_ioplug_set_param_list ( snd_pcm_ioplug_t *  ioplug,
int  type,
unsigned int  num_list,
const unsigned int *  list 
)

Set parameter as the list.

Parameters:
ioplug the ioplug handle
type parameter type
num_list number of available values
list the list of available values
Returns:
0 if successful, or a negative error code

Sets the parameter as the list. The available values of the given parameter type is restricted to the ones of the given list.

int snd_pcm_ioplug_set_param_minmax ( snd_pcm_ioplug_t *  ioplug,
int  type,
unsigned int  min,
unsigned int  max 
)

Set parameter as the min/max values.

Parameters:
ioplug the ioplug handle
type parameter type
min the minimum value
max the maximum value
Returns:
0 if successful, or a negative error code

Sets the parameter as the min/max values. The available values of the given parameter type is restricted between the given minimum and maximum values.

int snd_pcm_ioplug_set_state ( snd_pcm_ioplug_t *  ioplug,
snd_pcm_state_t  state 
)

Change the ioplug PCM status.

Parameters:
ioplug the ioplug handle
state the PCM status
Returns:
zero if successful or a negative error code

Changes the PCM status of the ioplug to the given value. This function can be used for external plugins to notify the status change, e.g. XRUN.

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