Main Page | Modules | Data Structures | Directories | File List | Data Fields | Globals | Related Pages | Examples

High level Control Interface
[Control Interface]


Typedefs

typedef _snd_hctl_elem snd_hctl_elem_t
typedef _snd_hctl snd_hctl_t
typedef int(* snd_hctl_compare_t )(const snd_hctl_elem_t *e1, const snd_hctl_elem_t *e2)
 Compare function for sorting HCTL elements.
typedef int(* snd_hctl_callback_t )(snd_hctl_t *hctl, unsigned int mask, snd_hctl_elem_t *elem)
 HCTL callback function.
typedef int(* snd_hctl_elem_callback_t )(snd_hctl_elem_t *elem, unsigned int mask)
 HCTL element callback function.

Functions

int snd_hctl_compare_fast (const snd_hctl_elem_t *c1, const snd_hctl_elem_t *c2)
 A "don't care" fast compare functions that may be used with snd_hctl_set_compare.
int snd_hctl_open (snd_hctl_t **hctl, const char *name, int mode)
 Opens an HCTL.
int snd_hctl_open_ctl (snd_hctl_t **hctlp, snd_ctl_t *ctl)
 Opens an HCTL.
int snd_hctl_close (snd_hctl_t *hctl)
 close HCTL handle
int snd_hctl_nonblock (snd_hctl_t *hctl, int nonblock)
 set nonblock mode
int snd_hctl_poll_descriptors_count (snd_hctl_t *hctl)
 get count of poll descriptors for HCTL handle
int snd_hctl_poll_descriptors (snd_hctl_t *hctl, struct pollfd *pfds, unsigned int space)
 get poll descriptors
int snd_hctl_poll_descriptors_revents (snd_hctl_t *ctl, struct pollfd *pfds, unsigned int nfds, unsigned short *revents)
 get returned events from poll descriptors
unsigned int snd_hctl_get_count (snd_hctl_t *hctl)
 Get number of loaded elements for an HCTL.
int snd_hctl_set_compare (snd_hctl_t *hctl, snd_hctl_compare_t hsort)
 Change HCTL compare function and reorder elements.
snd_hctl_elem_t * snd_hctl_first_elem (snd_hctl_t *hctl)
 get first element for an HCTL
snd_hctl_elem_t * snd_hctl_last_elem (snd_hctl_t *hctl)
 get last element for an HCTL
snd_hctl_elem_t * snd_hctl_find_elem (snd_hctl_t *hctl, const snd_ctl_elem_id_t *id)
 Search an HCTL element.
void snd_hctl_set_callback (snd_hctl_t *hctl, snd_hctl_callback_t callback)
 Set callback function for an HCTL.
void snd_hctl_set_callback_private (snd_hctl_t *hctl, void *data)
 Set callback private value for an HCTL.
void * snd_hctl_get_callback_private (snd_hctl_t *hctl)
 Get callback private value for an HCTL.
int snd_hctl_load (snd_hctl_t *hctl)
 Load an HCTL with all elements and sort them.
int snd_hctl_free (snd_hctl_t *hctl)
 free HCTL loaded elements
int snd_hctl_handle_events (snd_hctl_t *hctl)
 Handle pending HCTL events invoking callbacks.
const char * snd_hctl_name (snd_hctl_t *hctl)
 get identifier of HCTL handle
int snd_hctl_wait (snd_hctl_t *hctl, int timeout)
 Wait for a HCTL to become ready (i.e. at least one event pending).
snd_ctl_t * snd_hctl_ctl (snd_hctl_t *hctl)
 Get a ctl handle associated to the given hctl handle.
snd_hctl_elem_t * snd_hctl_elem_next (snd_hctl_elem_t *elem)
 get next HCTL element
snd_hctl_elem_t * snd_hctl_elem_prev (snd_hctl_elem_t *elem)
 get previous HCTL element
int snd_hctl_elem_info (snd_hctl_elem_t *elem, snd_ctl_elem_info_t *info)
 Get information for an HCTL element.
int snd_hctl_elem_read (snd_hctl_elem_t *elem, snd_ctl_elem_value_t *value)
 Get value for an HCTL element.
int snd_hctl_elem_write (snd_hctl_elem_t *elem, snd_ctl_elem_value_t *value)
 Set value for an HCTL element.
snd_hctl_t * snd_hctl_elem_get_hctl (snd_hctl_elem_t *elem)
 Get HCTL handle for an HCTL element.
void snd_hctl_elem_get_id (const snd_hctl_elem_t *obj, snd_ctl_elem_id_t *ptr)
 Get CTL element identifier of a CTL element id/value.
unsigned int snd_hctl_elem_get_numid (const snd_hctl_elem_t *obj)
 Get element numeric identifier of a CTL element id/value.
snd_ctl_elem_iface_t snd_hctl_elem_get_interface (const snd_hctl_elem_t *obj)
 Get interface part of CTL element identifier of a CTL element id/value.
unsigned int snd_hctl_elem_get_device (const snd_hctl_elem_t *obj)
 Get device part of CTL element identifier of a CTL element id/value.
unsigned int snd_hctl_elem_get_subdevice (const snd_hctl_elem_t *obj)
 Get subdevice part of CTL element identifier of a CTL element id/value.
const char * snd_hctl_elem_get_name (const snd_hctl_elem_t *obj)
 Get name part of CTL element identifier of a CTL element id/value.
unsigned int snd_hctl_elem_get_index (const snd_hctl_elem_t *obj)
 Get index part of CTL element identifier of a CTL element id/value.
void snd_hctl_elem_set_callback (snd_hctl_elem_t *obj, snd_hctl_elem_callback_t val)
 Set callback function for an HCTL element.
void * snd_hctl_elem_get_callback_private (const snd_hctl_elem_t *obj)
 Get callback private value for an HCTL element.
void snd_hctl_elem_set_callback_private (snd_hctl_elem_t *obj, void *val)
 Set callback private value for an HCTL element.

Detailed Description

The high level control interface. See High level control interface page for more details.

Typedef Documentation

typedef int(* snd_hctl_callback_t)(snd_hctl_t *hctl, unsigned int mask, snd_hctl_elem_t *elem)
 

HCTL callback function.

Parameters:
hctl HCTL handle
mask event mask
elem related HCTL element (if any)
Returns:
0 on success otherwise a negative error code

typedef int(* snd_hctl_compare_t)(const snd_hctl_elem_t *e1, const snd_hctl_elem_t *e2)
 

Compare function for sorting HCTL elements.

Parameters:
e1 First element
e2 Second element
Returns:
-1 if e1 < e2, 0 if e1 == e2, 1 if e1 > e2

typedef int(* snd_hctl_elem_callback_t)(snd_hctl_elem_t *elem, unsigned int mask)
 

HCTL element callback function.

Parameters:
elem HCTL element
mask event mask
Returns:
0 on success otherwise a negative error code

typedef struct _snd_hctl_elem snd_hctl_elem_t
 

HCTL element handle

typedef struct _snd_hctl snd_hctl_t
 

HCTL handle

Function Documentation

int snd_hctl_close (  snd_hctl_t *  hctl  ) 
 

close HCTL handle

Parameters:
hctl HCTL handle
Returns:
0 on success otherwise a negative error code
Closes the specified HCTL handle and frees all associated resources.

int snd_hctl_compare_fast (  const snd_hctl_elem_t *  c1,
const snd_hctl_elem_t *  c2
) 
 

A "don't care" fast compare functions that may be used with snd_hctl_set_compare.

Parameters:
c1 First HCTL element
c2 Second HCTL element
Returns:
-1 if c1 < c2, 0 if c1 == c2, 1 if c1 > c2

snd_ctl_t* snd_hctl_ctl (  snd_hctl_t *  hctl  ) 
 

Get a ctl handle associated to the given hctl handle.

Parameters:
hctl HCTL handle
Returns:
a ctl handle otherwise NULL

void* snd_hctl_elem_get_callback_private (  const snd_hctl_elem_t *  obj  ) 
 

Get callback private value for an HCTL element.

Parameters:
obj HCTL element
Returns:
callback private value

unsigned int snd_hctl_elem_get_device (  const snd_hctl_elem_t *  obj  ) 
 

Get device part of CTL element identifier of a CTL element id/value.

Parameters:
obj CTL element id/value
Returns:
device part of element identifier

snd_hctl_t* snd_hctl_elem_get_hctl (  snd_hctl_elem_t *  elem  ) 
 

Get HCTL handle for an HCTL element.

Parameters:
elem HCTL element
Returns:
HCTL handle

void snd_hctl_elem_get_id (  const snd_hctl_elem_t *  obj,
snd_ctl_elem_id_t *  ptr
) 
 

Get CTL element identifier of a CTL element id/value.

Parameters:
obj CTL element id/value
ptr Pointer to returned CTL element identifier

unsigned int snd_hctl_elem_get_index (  const snd_hctl_elem_t *  obj  ) 
 

Get index part of CTL element identifier of a CTL element id/value.

Parameters:
obj CTL element id/value
Returns:
index part of element identifier

snd_ctl_elem_iface_t snd_hctl_elem_get_interface (  const snd_hctl_elem_t *  obj  ) 
 

Get interface part of CTL element identifier of a CTL element id/value.

Parameters:
obj CTL element id/value
Returns:
interface part of element identifier

const char* snd_hctl_elem_get_name (  const snd_hctl_elem_t *  obj  ) 
 

Get name part of CTL element identifier of a CTL element id/value.

Parameters:
obj CTL element id/value
Returns:
name part of element identifier

unsigned int snd_hctl_elem_get_numid (  const snd_hctl_elem_t *  obj  ) 
 

Get element numeric identifier of a CTL element id/value.

Parameters:
obj CTL element id/value
Returns:
element numeric identifier

unsigned int snd_hctl_elem_get_subdevice (  const snd_hctl_elem_t *  obj  ) 
 

Get subdevice part of CTL element identifier of a CTL element id/value.

Parameters:
obj CTL element id/value
Returns:
subdevice part of element identifier

int snd_hctl_elem_info (  snd_hctl_elem_t *  elem,
snd_ctl_elem_info_t *  info
) 
 

Get information for an HCTL element.

Parameters:
elem HCTL element
info HCTL element information
Returns:
0 otherwise a negative error code on failure

snd_hctl_elem_t* snd_hctl_elem_next (  snd_hctl_elem_t *  elem  ) 
 

get next HCTL element

Parameters:
elem HCTL element
Returns:
pointer to next element

snd_hctl_elem_t* snd_hctl_elem_prev (  snd_hctl_elem_t *  elem  ) 
 

get previous HCTL element

Parameters:
elem HCTL element
Returns:
pointer to previous element

int snd_hctl_elem_read (  snd_hctl_elem_t *  elem,
snd_ctl_elem_value_t *  value
) 
 

Get value for an HCTL element.

Parameters:
elem HCTL element
value HCTL element value
Returns:
0 otherwise a negative error code on failure

void snd_hctl_elem_set_callback (  snd_hctl_elem_t *  obj,
snd_hctl_elem_callback_t  val
) 
 

Set callback function for an HCTL element.

Parameters:
obj HCTL element
val callback function

void snd_hctl_elem_set_callback_private (  snd_hctl_elem_t *  obj,
void *  val
) 
 

Set callback private value for an HCTL element.

Parameters:
obj HCTL element
val callback private value

int snd_hctl_elem_write (  snd_hctl_elem_t *  elem,
snd_ctl_elem_value_t *  value
) 
 

Set value for an HCTL element.

Parameters:
elem HCTL element
value HCTL element value
Returns:
0 otherwise a negative error code on failure

snd_hctl_elem_t* snd_hctl_find_elem (  snd_hctl_t *  hctl,
const snd_ctl_elem_id_t *  id
) 
 

Search an HCTL element.

Parameters:
hctl HCTL handle
id Element identifier
Returns:
pointer to found HCTL element or NULL if it does not exists

snd_hctl_elem_t* snd_hctl_first_elem (  snd_hctl_t *  hctl  ) 
 

get first element for an HCTL

Parameters:
hctl HCTL handle
Returns:
pointer to first element

int snd_hctl_free (  snd_hctl_t *  hctl  ) 
 

free HCTL loaded elements

Parameters:
hctl HCTL handle
Returns:
0 on success otherwise a negative error code

void* snd_hctl_get_callback_private (  snd_hctl_t *  hctl  ) 
 

Get callback private value for an HCTL.

Parameters:
hctl HCTL handle
Returns:
callback private value

unsigned int snd_hctl_get_count (  snd_hctl_t *  hctl  ) 
 

Get number of loaded elements for an HCTL.

Parameters:
hctl HCTL handle
Returns:
elements count

int snd_hctl_handle_events (  snd_hctl_t *  hctl  ) 
 

Handle pending HCTL events invoking callbacks.

Parameters:
hctl HCTL handle
Returns:
0 otherwise a negative error code on failure

snd_hctl_elem_t* snd_hctl_last_elem (  snd_hctl_t *  hctl  ) 
 

get last element for an HCTL

Parameters:
hctl HCTL handle
Returns:
pointer to last element

int snd_hctl_load (  snd_hctl_t *  hctl  ) 
 

Load an HCTL with all elements and sort them.

Parameters:
hctl HCTL handle
Returns:
0 on success otherwise a negative error code

const char* snd_hctl_name (  snd_hctl_t *  hctl  ) 
 

get identifier of HCTL handle

Parameters:
hctl HCTL handle
Returns:
ascii identifier of HCTL handle
Returns the ASCII identifier of given HCTL handle. It's the same identifier specified in snd_hctl_open().

int snd_hctl_nonblock (  snd_hctl_t *  hctl,
int  nonblock
) 
 

set nonblock mode

Parameters:
hctl HCTL handle
nonblock 0 = block, 1 = nonblock mode
Returns:
0 on success otherwise a negative error code

int snd_hctl_open (  snd_hctl_t **  hctlp,
const char *  name,
int  mode
) 
 

Opens an HCTL.

Parameters:
hctlp Returned HCTL handle
name ASCII identifier of the underlying CTL handle
mode Open mode (see SND_CTL_NONBLOCK, SND_CTL_ASYNC)
Returns:
0 on success otherwise a negative error code

int snd_hctl_open_ctl (  snd_hctl_t **  hctlp,
snd_ctl_t *  ctl
) 
 

Opens an HCTL.

Parameters:
hctlp Returned HCTL handle
ctl underlying CTL handle
Returns:
0 on success otherwise a negative error code

int snd_hctl_poll_descriptors (  snd_hctl_t *  hctl,
struct pollfd *  pfds,
unsigned int  space
) 
 

get poll descriptors

Parameters:
hctl HCTL handle
pfds array of poll descriptors
space space in the poll descriptor array
Returns:
count of filled descriptors

int snd_hctl_poll_descriptors_count (  snd_hctl_t *  hctl  ) 
 

get count of poll descriptors for HCTL handle

Parameters:
hctl HCTL handle
Returns:
count of poll descriptors

int snd_hctl_poll_descriptors_revents (  snd_hctl_t *  hctl,
struct pollfd *  pfds,
unsigned int  nfds,
unsigned short *  revents
) 
 

get returned events from poll descriptors

Parameters:
hctl HCTL handle
pfds array of poll descriptors
nfds count of poll descriptors
revents returned events
Returns:
zero if success, otherwise a negative error code

void snd_hctl_set_callback (  snd_hctl_t *  hctl,
snd_hctl_callback_t  callback
) 
 

Set callback function for an HCTL.

Parameters:
hctl HCTL handle
callback callback function

void snd_hctl_set_callback_private (  snd_hctl_t *  hctl,
void *  callback_private
) 
 

Set callback private value for an HCTL.

Parameters:
hctl HCTL handle
callback_private callback private value

int snd_hctl_set_compare (  snd_hctl_t *  hctl,
snd_hctl_compare_t  compare
) 
 

Change HCTL compare function and reorder elements.

Parameters:
hctl HCTL handle
compare Element compare function
Returns:
0 on success otherwise a negative error code

int snd_hctl_wait (  snd_hctl_t *  hctl,
int  timeout
) 
 

Wait for a HCTL to become ready (i.e. at least one event pending).

Parameters:
hctl HCTL handle
timeout maximum time in milliseconds to wait
Returns:
0 otherwise a negative error code on failure

Generated on Sun Sep 3 10:36:54 2006 for ALSA project - the C library reference by  doxygen 1.4.2