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Typedefs | Functions
High level Control Interface

Typedefs

typedef struct _snd_hctl_elem snd_hctl_elem_t
 
typedef struct _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. More...
 
typedef int(* snd_hctl_callback_t )(snd_hctl_t *hctl, unsigned int mask, snd_hctl_elem_t *elem)
 HCTL callback function. More...
 
typedef int(* snd_hctl_elem_callback_t )(snd_hctl_elem_t *elem, unsigned int mask)
 HCTL element callback function. More...
 

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. More...
 
int snd_hctl_open (snd_hctl_t **hctl, const char *name, int mode)
 Opens an HCTL. More...
 
int snd_hctl_open_ctl (snd_hctl_t **hctlp, snd_ctl_t *ctl)
 Opens an HCTL. More...
 
int snd_hctl_close (snd_hctl_t *hctl)
 close HCTL handle More...
 
int snd_hctl_nonblock (snd_hctl_t *hctl, int nonblock)
 set nonblock mode More...
 
int snd_hctl_poll_descriptors_count (snd_hctl_t *hctl)
 get count of poll descriptors for HCTL handle More...
 
int snd_hctl_poll_descriptors (snd_hctl_t *hctl, struct pollfd *pfds, unsigned int space)
 get poll descriptors More...
 
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 More...
 
unsigned int snd_hctl_get_count (snd_hctl_t *hctl)
 Get number of loaded elements for an HCTL. More...
 
int snd_hctl_set_compare (snd_hctl_t *hctl, snd_hctl_compare_t hsort)
 Change HCTL compare function and reorder elements. More...
 
snd_hctl_elem_tsnd_hctl_first_elem (snd_hctl_t *hctl)
 get first element for an HCTL More...
 
snd_hctl_elem_tsnd_hctl_last_elem (snd_hctl_t *hctl)
 get last element for an HCTL More...
 
snd_hctl_elem_tsnd_hctl_find_elem (snd_hctl_t *hctl, const snd_ctl_elem_id_t *id)
 Search an HCTL element. More...
 
void snd_hctl_set_callback (snd_hctl_t *hctl, snd_hctl_callback_t callback)
 Set callback function for an HCTL. More...
 
void snd_hctl_set_callback_private (snd_hctl_t *hctl, void *data)
 Set callback private value for an HCTL. More...
 
void * snd_hctl_get_callback_private (snd_hctl_t *hctl)
 Get callback private value for an HCTL. More...
 
int snd_hctl_load (snd_hctl_t *hctl)
 Load an HCTL with all elements and sort them. More...
 
int snd_hctl_free (snd_hctl_t *hctl)
 free HCTL loaded elements More...
 
int snd_hctl_handle_events (snd_hctl_t *hctl)
 Handle pending HCTL events invoking callbacks. More...
 
const char * snd_hctl_name (snd_hctl_t *hctl)
 get identifier of HCTL handle More...
 
int snd_hctl_wait (snd_hctl_t *hctl, int timeout)
 Wait for a HCTL to become ready (i.e. at least one event pending) More...
 
snd_ctl_tsnd_hctl_ctl (snd_hctl_t *hctl)
 Get a ctl handle associated to the given hctl handle. More...
 
snd_hctl_elem_tsnd_hctl_elem_next (snd_hctl_elem_t *elem)
 get next HCTL element More...
 
snd_hctl_elem_tsnd_hctl_elem_prev (snd_hctl_elem_t *elem)
 get previous HCTL element More...
 
int snd_hctl_elem_info (snd_hctl_elem_t *elem, snd_ctl_elem_info_t *info)
 Get information for an HCTL element. More...
 
int snd_hctl_elem_read (snd_hctl_elem_t *elem, snd_ctl_elem_value_t *value)
 Get value for an HCTL element. More...
 
int snd_hctl_elem_write (snd_hctl_elem_t *elem, snd_ctl_elem_value_t *value)
 Set value for an HCTL element. More...
 
int snd_hctl_elem_tlv_read (snd_hctl_elem_t *elem, unsigned int *tlv, unsigned int tlv_size)
 Get TLV value for an HCTL element. More...
 
int snd_hctl_elem_tlv_write (snd_hctl_elem_t *elem, const unsigned int *tlv)
 Set TLV value for an HCTL element. More...
 
int snd_hctl_elem_tlv_command (snd_hctl_elem_t *elem, const unsigned int *tlv)
 Set TLV value for an HCTL element. More...
 
snd_hctl_tsnd_hctl_elem_get_hctl (snd_hctl_elem_t *elem)
 Get HCTL handle for an HCTL element. More...
 
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. More...
 
unsigned int snd_hctl_elem_get_numid (const snd_hctl_elem_t *obj)
 Get element numeric identifier of a CTL element id/value. More...
 
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. More...
 
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. More...
 
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. More...
 
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. More...
 
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. More...
 
void snd_hctl_elem_set_callback (snd_hctl_elem_t *obj, snd_hctl_elem_callback_t val)
 Set callback function for an HCTL element. More...
 
void * snd_hctl_elem_get_callback_private (const snd_hctl_elem_t *obj)
 Get callback private value for an HCTL element. More...
 
void snd_hctl_elem_set_callback_private (snd_hctl_elem_t *obj, void *val)
 Set callback private value for an HCTL element. More...
 

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
hctlHCTL handle
maskevent mask
elemrelated 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
e1First element
e2Second 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
elemHCTL element
maskevent 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
hctlHCTL 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
c1First HCTL element
c2Second 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
hctlHCTL 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
objHCTL 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
objCTL 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
elemHCTL 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
objCTL element id/value
ptrPointer 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
objCTL 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
objCTL 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
objCTL 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
objCTL 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
objCTL 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
elemHCTL element
infoHCTL 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
elemHCTL element
Returns
pointer to next element
snd_hctl_elem_t* snd_hctl_elem_prev ( snd_hctl_elem_t elem)

get previous HCTL element

Parameters
elemHCTL 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
elemHCTL element
valueHCTL 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
objHCTL element
valcallback function
void snd_hctl_elem_set_callback_private ( snd_hctl_elem_t obj,
void *  val 
)

Set callback private value for an HCTL element.

Parameters
objHCTL element
valcallback private value
int snd_hctl_elem_tlv_command ( snd_hctl_elem_t elem,
const unsigned int *  tlv 
)

Set TLV value for an HCTL element.

Parameters
elemHCTL element
tlvTLV array for value
Return values
0on success
>1on success when value was changed
<0a negative error code on failure
int snd_hctl_elem_tlv_read ( snd_hctl_elem_t elem,
unsigned int *  tlv,
unsigned int  tlv_size 
)

Get TLV value for an HCTL element.

Parameters
elemHCTL element
tlvTLV array for value
tlv_sizesize of TLV array in bytes
Returns
0 otherwise a negative error code on failure
int snd_hctl_elem_tlv_write ( snd_hctl_elem_t elem,
const unsigned int *  tlv 
)

Set TLV value for an HCTL element.

Parameters
elemHCTL element
tlvTLV array for value
Return values
0on success
>1on success when value was changed
<0a negative error code on failure
int snd_hctl_elem_write ( snd_hctl_elem_t elem,
snd_ctl_elem_value_t value 
)

Set value for an HCTL element.

Parameters
elemHCTL element
valueHCTL element value
Return values
0on success
>1on success when value was changed
<0a 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
hctlHCTL handle
idElement 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
hctlHCTL handle
Returns
pointer to first element
int snd_hctl_free ( snd_hctl_t hctl)

free HCTL loaded elements

Parameters
hctlHCTL 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
hctlHCTL handle
Returns
callback private value
unsigned int snd_hctl_get_count ( snd_hctl_t hctl)

Get number of loaded elements for an HCTL.

Parameters
hctlHCTL handle
Returns
elements count
int snd_hctl_handle_events ( snd_hctl_t hctl)

Handle pending HCTL events invoking callbacks.

Parameters
hctlHCTL 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
hctlHCTL handle
Returns
pointer to last element
int snd_hctl_load ( snd_hctl_t hctl)

Load an HCTL with all elements and sort them.

Parameters
hctlHCTL 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
hctlHCTL 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
hctlHCTL handle
nonblock0 = 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
hctlpReturned HCTL handle
nameASCII identifier of the underlying CTL handle
modeOpen 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
hctlpReturned HCTL handle
ctlunderlying 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
hctlHCTL handle
pfdsarray of poll descriptors
spacespace 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
hctlHCTL 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
hctlHCTL handle
pfdsarray of poll descriptors
nfdscount of poll descriptors
reventsreturned 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
hctlHCTL handle
callbackcallback function
void snd_hctl_set_callback_private ( snd_hctl_t hctl,
void *  callback_private 
)

Set callback private value for an HCTL.

Parameters
hctlHCTL handle
callback_privatecallback private value
int snd_hctl_set_compare ( snd_hctl_t hctl,
snd_hctl_compare_t  compare 
)

Change HCTL compare function and reorder elements.

Parameters
hctlHCTL handle
compareElement 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
hctlHCTL handle
timeoutmaximum time in milliseconds to wait
Returns
a positive value on success otherwise a negative error code
Return values
0timeout occurred
1an event is pending

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