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ALSA project - the C library reference
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HCTL Interface - High Level CTL. More...
Functions | |
| int | snd_hctl_open (snd_hctl_t **hctlp, 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 | |
| const char * | snd_hctl_name (snd_hctl_t *hctl) |
| get identifier of HCTL handle | |
| int | snd_hctl_nonblock (snd_hctl_t *hctl, int nonblock) |
| set nonblock mode | |
| int | snd_hctl_async (snd_hctl_t *hctl, int sig, pid_t pid) |
| set async 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 *hctl, struct pollfd *pfds, unsigned int nfds, unsigned short *revents) |
| get returned events from poll descriptors | |
| int | snd_hctl_free (snd_hctl_t *hctl) |
| free HCTL loaded elements | |
| int | snd_hctl_set_compare (snd_hctl_t *hctl, snd_hctl_compare_t compare) |
| Change HCTL compare function and reorder elements. | |
| 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. | |
| 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_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 | |
| snd_hctl_elem_t * | snd_hctl_find_elem (snd_hctl_t *hctl, const snd_ctl_elem_id_t *id) |
| Search an HCTL element. | |
| int | snd_hctl_load (snd_hctl_t *hctl) |
| Load an HCTL with all elements and sort them. | |
| 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 *callback_private) |
| Set callback private value for an HCTL. | |
| void * | snd_hctl_get_callback_private (snd_hctl_t *hctl) |
| Get callback private value for an HCTL. | |
| unsigned int | snd_hctl_get_count (snd_hctl_t *hctl) |
| Get number of loaded elements for an HCTL. | |
| 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. | |
| int | snd_hctl_handle_events (snd_hctl_t *hctl) |
| Handle pending HCTL events invoking callbacks. | |
| 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_set_callback_private (snd_hctl_elem_t *obj, void *val) |
| Set callback private value 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. | |
HCTL Interface - High Level CTL.
HCTL interface is designed to access preloaded and sorted primitive controls. Callbacks may be used for event handling. See High level control interface page for more details.
| int snd_hctl_async | ( | snd_hctl_t * | hctl, |
| int | sig, | ||
| pid_t | pid ) |
set async mode
| hctl | HCTL handle |
| sig | Signal to raise: < 0 disable, 0 default (SIGIO) |
| pid | Process ID to signal: 0 current |
A signal is raised when a change happens.