ALSA project – the C library reference

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.
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.
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.
int snd_hctl_elem_tlv_write (snd_hctl_elem_t *elem, const unsigned int *tlv)
Set TLV value for an HCTL element.
int snd_hctl_elem_tlv_command (snd_hctl_elem_t *elem, const unsigned int *tlv)
Set TLV 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.

 


http://www.alsa-project.org/alsa-doc/alsa-lib/group___h_control.html

 

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