ALSA project - the C library reference: Control Interface

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Control Interface

## Modules
| High level Control Interface
| Setup Control Interface

## Data Structures
struct | snd_aes_iec958_t

## Macros
#define | SND_CONTROL_DLSYM_VERSION _dlsym_control_001
#define | SND_CTL_EVENT_MASK_REMOVE
#define | SND_CTL_EVENT_MASK_VALUE
#define | SND_CTL_EVENT_MASK_INFO
#define | SND_CTL_EVENT_MASK_ADD
#define | SND_CTL_EVENT_MASK_TLV
#define | SND_CTL_NAME_NONE ""
#define | SND_CTL_NAME_PLAYBACK "Playback "
#define | SND_CTL_NAME_CAPTURE "Capture "
#define | SND_CTL_NAME_IEC958_NONE ""
#define | SND_CTL_NAME_IEC958_SWITCH "Switch"
#define | SND_CTL_NAME_IEC958_VOLUME "Volume"
#define | SND_CTL_NAME_IEC958_DEFAULT "Default"
#define | SND_CTL_NAME_IEC958_MASK "Mask"
#define | SND_CTL_NAME_IEC958_CON_MASK "Con Mask"
#define | SND_CTL_NAME_IEC958_PRO_MASK "Pro Mask"
#define | SND_CTL_NAME_IEC958_PCM_STREAM "PCM Stream"
#define | SND_CTL_NAME_IEC958(expl, direction, what) "IEC958 " expl SND_CTL_NAME_##direction SND_CTL_NAME_IEC958_##what
#define | SND_CTL_POWER_MASK 0xff00
#define | SND_CTL_POWER_D0 0x0000
#define | SND_CTL_POWER_D1 0x0100
#define | SND_CTL_POWER_D2 0x0200
#define | SND_CTL_POWER_D3 0x0300
#define | SND_CTL_POWER_D3hot (SND_CTL_POWER_D3|0x0000)
#define | SND_CTL_POWER_D3cold (SND_CTL_POWER_D3|0x0001)
#define | SND_CTL_TLVT_CONTAINER 0x0000
#define | SND_CTL_TLVT_DB_SCALE 0x0001
#define | SND_CTL_TLVT_DB_LINEAR 0x0002
#define | SND_CTL_TLVT_DB_RANGE 0x0003
#define | SND_CTL_TLVT_DB_MINMAX 0x0004
#define | SND_CTL_TLVT_DB_MINMAX_MUTE 0x0005
#define | SND_CTL_TLV_DB_GAIN_MUTE -9999999
#define | SND_CTL_TLVT_CHMAP_FIXED 0x00101
#define | SND_CTL_TLVT_CHMAP_VAR 0x00102
#define | SND_CTL_TLVT_CHMAP_PAIRED 0x00103
#define | SND_CTL_NONBLOCK
#define | SND_CTL_ASYNC
#define | SND_CTL_READONLY
#define | SND_SCTL_NOFREE 0x0001
#define | snd_ctl_elem_id_alloca(ptr)
| allocate an invalid snd_ctl_elem_id_t using standard alloca More...
#define | snd_ctl_card_info_alloca(ptr)
| allocate an invalid snd_ctl_card_info_t using standard alloca More...
#define | snd_ctl_event_alloca(ptr)
| allocate an invalid snd_ctl_event_t using standard alloca More...
#define | snd_ctl_elem_list_alloca(ptr)
| allocate an invalid snd_ctl_elem_list_t using standard alloca More...
#define | snd_ctl_elem_info_alloca(ptr)
| allocate an invalid snd_ctl_elem_info_t using standard alloca More...
#define | snd_ctl_elem_value_alloca(ptr)
| allocate an invalid snd_ctl_elem_value_t using standard alloca More...

## Typedefs
typedef struct _snd_ctl_card_info | snd_ctl_card_info_t
typedef struct _snd_ctl_elem_id | snd_ctl_elem_id_t
typedef struct _snd_ctl_elem_list | snd_ctl_elem_list_t
typedef struct _snd_ctl_elem_info | snd_ctl_elem_info_t
typedef struct _snd_ctl_elem_value | snd_ctl_elem_value_t
typedef struct _snd_ctl_event | snd_ctl_event_t
typedef struct _snd_ctl | snd_ctl_t
typedef struct _snd_sctl | snd_sctl_t

## Enumerations
enum | snd_ctl_elem_type_t { SND_CTL_ELEM_TYPE_NONE = 0, SND_CTL_ELEM_TYPE_BOOLEAN, SND_CTL_ELEM_TYPE_INTEGER, SND_CTL_ELEM_TYPE_ENUMERATED, SND_CTL_ELEM_TYPE_BYTES, SND_CTL_ELEM_TYPE_IEC958, SND_CTL_ELEM_TYPE_INTEGER64, SND_CTL_ELEM_TYPE_LAST = SND_CTL_ELEM_TYPE_INTEGER64 }
enum | snd_ctl_elem_iface_t { SND_CTL_ELEM_IFACE_CARD = 0, SND_CTL_ELEM_IFACE_HWDEP, SND_CTL_ELEM_IFACE_MIXER, SND_CTL_ELEM_IFACE_PCM, SND_CTL_ELEM_IFACE_RAWMIDI, SND_CTL_ELEM_IFACE_TIMER, SND_CTL_ELEM_IFACE_SEQUENCER, SND_CTL_ELEM_IFACE_LAST = SND_CTL_ELEM_IFACE_SEQUENCER }
enum | snd_ctl_event_type_t { SND_CTL_EVENT_ELEM = 0, SND_CTL_EVENT_LAST = SND_CTL_EVENT_ELEM }
enum | snd_ctl_type_t { SND_CTL_TYPE_HW, SND_CTL_TYPE_SHM, SND_CTL_TYPE_INET, SND_CTL_TYPE_EXT }

## Functions
int | snd_card_load (int card)
| Try to load the driver for a card. More...
int | snd_card_next (int *card)
| Try to determine the next card. More...
int | snd_card_get_index (const char *name)
| Convert card string to an integer value. More...
int | snd_card_get_name (int card, char **name)
| Obtain the card name. More...
int | snd_card_get_longname (int card, char **name)
| Obtain the card long name. More...
int | snd_device_name_hint (int card, const char *iface, void ***hints)
| Get a set of device name hints. More...
int | snd_device_name_free_hint (void **hints)
| Free a list of device name hints. More...
char * | snd_device_name_get_hint (const void *hint, const char *id)
| Extract a value from a hint. More...
int | snd_ctl_open (snd_ctl_t **ctl, const char *name, int mode)
| Opens a CTL. More...
int | snd_ctl_open_lconf (snd_ctl_t **ctl, const char *name, int mode, snd_config_t *lconf)
| Opens a CTL using local configuration. More...
int | snd_ctl_open_fallback (snd_ctl_t **ctl, snd_config_t *root, const char *name, const char *orig_name, int mode)
| Opens a fallback CTL. More...
int | snd_ctl_close (snd_ctl_t *ctl)
| close CTL handle More...
int | snd_ctl_nonblock (snd_ctl_t *ctl, int nonblock)
| set nonblock mode More...
int | snd_async_add_ctl_handler (snd_async_handler_t **handler, snd_ctl_t *ctl, snd_async_callback_t callback, void *private_data)
| Add an async handler for a CTL. More...
snd_ctl_t * | snd_async_handler_get_ctl (snd_async_handler_t *handler)
| Return CTL handle related to an async handler. More...
int | snd_ctl_poll_descriptors_count (snd_ctl_t *ctl)
| get count of poll descriptors for CTL handle More...
int | snd_ctl_poll_descriptors (snd_ctl_t *ctl, struct pollfd *pfds, unsigned int space)
| get poll descriptors More...
int | snd_ctl_poll_descriptors_revents (snd_ctl_t *ctl, struct pollfd *pfds, unsigned int nfds, unsigned short *revents)
| get returned events from poll descriptors More...
int | snd_ctl_subscribe_events (snd_ctl_t *ctl, int subscribe)
| Ask to be informed about events (poll, snd_async_add_ctl_handler, snd_ctl_read) More...
int | snd_ctl_card_info (snd_ctl_t *ctl, snd_ctl_card_info_t *info)
| Get card related information. More...
int | snd_ctl_elem_list (snd_ctl_t *ctl, snd_ctl_elem_list_t *list)
| Get a list of element identifiers. More...
int | snd_ctl_elem_info (snd_ctl_t *ctl, snd_ctl_elem_info_t *info)
| Get CTL element information. More...
int | snd_ctl_elem_read (snd_ctl_t *ctl, snd_ctl_elem_value_t *data)
| Get CTL element value. More...
int | snd_ctl_elem_write (snd_ctl_t *ctl, snd_ctl_elem_value_t *data)
| Set CTL element value. More...
int | snd_ctl_elem_lock (snd_ctl_t *ctl, snd_ctl_elem_id_t *id)
| Lock CTL element. More...
int | snd_ctl_elem_unlock (snd_ctl_t *ctl, snd_ctl_elem_id_t *id)
| Unlock CTL element. More...
int | snd_ctl_elem_tlv_read (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, unsigned int *tlv, unsigned int tlv_size)
| Read structured data from an element set to given buffer. More...
int | snd_ctl_elem_tlv_write (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, const unsigned int *tlv)
| Write structured data from given buffer to an element set. More...
int | snd_ctl_elem_tlv_command (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, const unsigned int *tlv)
| Process structured data from given buffer for an element set. More...
int | snd_ctl_set_power_state (snd_ctl_t *ctl, unsigned int state)
| Set Power State to given SND_CTL_POWER_* value and do the power management. More...
int | snd_ctl_get_power_state (snd_ctl_t *ctl, unsigned int *state)
| Get actual Power State. More...
int | snd_ctl_read (snd_ctl_t *ctl, snd_ctl_event_t *event)
| Read an event. More...
int | snd_ctl_wait (snd_ctl_t *ctl, int timeout)
| Wait for a CTL to become ready (i.e. at least one event pending) More...
const char * | snd_ctl_name (snd_ctl_t *ctl)
| get identifier of CTL handle More...
snd_ctl_type_t | snd_ctl_type (snd_ctl_t *ctl)
| get type of CTL handle More...
const char * | snd_ctl_elem_type_name (snd_ctl_elem_type_t type)
| get name of a CTL element type More...
const char * | snd_ctl_elem_iface_name (snd_ctl_elem_iface_t iface)
| get name of a CTL element related interface More...
const char * | snd_ctl_event_type_name (snd_ctl_event_type_t type)
| get name of a CTL event type More...
unsigned int | snd_ctl_event_elem_get_mask (const snd_ctl_event_t *obj)
| Get event mask for an element related event. More...
unsigned int | snd_ctl_event_elem_get_numid (const snd_ctl_event_t *obj)
| Get element numeric identifier for an element related event. More...
void | snd_ctl_event_elem_get_id (const snd_ctl_event_t *obj, snd_ctl_elem_id_t *ptr)
| Get CTL element identifier for an element related event. More...
snd_ctl_elem_iface_t | snd_ctl_event_elem_get_interface (const snd_ctl_event_t *obj)
| Get interface part of CTL element identifier for an element related event. More...
unsigned int | snd_ctl_event_elem_get_device (const snd_ctl_event_t *obj)
| Get device part of CTL element identifier for an element related event. More...
unsigned int | snd_ctl_event_elem_get_subdevice (const snd_ctl_event_t *obj)
| Get subdevice part of CTL element identifier for an element related event. More...
const char * | snd_ctl_event_elem_get_name (const snd_ctl_event_t *obj)
| Get name part of CTL element identifier for an element related event. More...
unsigned int | snd_ctl_event_elem_get_index (const snd_ctl_event_t *obj)
| Get index part of CTL element identifier for an element related event. More...
int | snd_ctl_elem_list_alloc_space (snd_ctl_elem_list_t *obj, unsigned int entries)
| allocate space for CTL element identifiers list More...
void | snd_ctl_elem_list_free_space (snd_ctl_elem_list_t *obj)
| free previously allocated space for CTL element identifiers list More...
char * | snd_ctl_ascii_elem_id_get (snd_ctl_elem_id_t *id)
| return ASCII CTL element identifier name More...
int | snd_ctl_ascii_elem_id_parse (snd_ctl_elem_id_t *dst, const char *str)
| parse ASCII string as CTL element identifier More...
int | snd_ctl_ascii_value_parse (snd_ctl_t *handle, snd_ctl_elem_value_t *dst, snd_ctl_elem_info_t *info, const char *value)
| parse ASCII string as CTL element value More...
size_t | snd_ctl_elem_id_sizeof (void)
| get size of snd_ctl_elem_id_t More...
int | snd_ctl_elem_id_malloc (snd_ctl_elem_id_t **ptr)
| allocate an invalid snd_ctl_elem_id_t using standard malloc More...
void | snd_ctl_elem_id_free (snd_ctl_elem_id_t *obj)
| frees a previously allocated snd_ctl_elem_id_t More...
void | snd_ctl_elem_id_clear (snd_ctl_elem_id_t *obj)
| clear given snd_ctl_elem_id_t object More...
void | snd_ctl_elem_id_copy (snd_ctl_elem_id_t *dst, const snd_ctl_elem_id_t *src)
| copy one snd_ctl_elem_id_t to another More...
unsigned int | snd_ctl_elem_id_get_numid (const snd_ctl_elem_id_t *obj)
| Get numeric identifier from a CTL element identifier. More...
snd_ctl_elem_iface_t | snd_ctl_elem_id_get_interface (const snd_ctl_elem_id_t *obj)
| Get interface part of a CTL element identifier. More...
unsigned int | snd_ctl_elem_id_get_device (const snd_ctl_elem_id_t *obj)
| Get device part of a CTL element identifier. More...
unsigned int | snd_ctl_elem_id_get_subdevice (const snd_ctl_elem_id_t *obj)
| Get subdevice part of a CTL element identifier. More...
const char * | snd_ctl_elem_id_get_name (const snd_ctl_elem_id_t *obj)
| Get name part of a CTL element identifier. More...
unsigned int | snd_ctl_elem_id_get_index (const snd_ctl_elem_id_t *obj)
| Get index part of a CTL element identifier. More...
void | snd_ctl_elem_id_set_numid (snd_ctl_elem_id_t *obj, unsigned int val)
| Set numeric identifier for a CTL element identifier. More...
void | snd_ctl_elem_id_set_interface (snd_ctl_elem_id_t *obj, snd_ctl_elem_iface_t val)
| Set interface part for a CTL element identifier. More...
void | snd_ctl_elem_id_set_device (snd_ctl_elem_id_t *obj, unsigned int val)
| Set device part for a CTL element identifier. More...
void | snd_ctl_elem_id_set_subdevice (snd_ctl_elem_id_t *obj, unsigned int val)
| Set subdevice part for a CTL element identifier. More...
void | snd_ctl_elem_id_set_name (snd_ctl_elem_id_t *obj, const char *val)
| Set name part for a CTL element identifier. More...
void | snd_ctl_elem_id_set_index (snd_ctl_elem_id_t *obj, unsigned int val)
| Set index part for a CTL element identifier. More...
size_t | snd_ctl_card_info_sizeof (void)
| get size of snd_ctl_card_info_t More...
int | snd_ctl_card_info_malloc (snd_ctl_card_info_t **ptr)
| allocate an invalid snd_ctl_card_info_t using standard malloc More...
void | snd_ctl_card_info_free (snd_ctl_card_info_t *obj)
| frees a previously allocated snd_ctl_card_info_t More...
void | snd_ctl_card_info_clear (snd_ctl_card_info_t *obj)
| clear given snd_ctl_card_info_t object More...
void | snd_ctl_card_info_copy (snd_ctl_card_info_t *dst, const snd_ctl_card_info_t *src)
| copy one snd_ctl_card_info_t to another More...
int | snd_ctl_card_info_get_card (const snd_ctl_card_info_t *obj)
| Get card number from a CTL card info. More...
const char * | snd_ctl_card_info_get_id (const snd_ctl_card_info_t *obj)
| Get card identifier from a CTL card info. More...
const char * | snd_ctl_card_info_get_driver (const snd_ctl_card_info_t *obj)
| Get card driver name from a CTL card info. More...
const char * | snd_ctl_card_info_get_name (const snd_ctl_card_info_t *obj)
| Get card name from a CTL card info. More...
const char * | snd_ctl_card_info_get_longname (const snd_ctl_card_info_t *obj)
| Get card long name from a CTL card info. More...
const char * | snd_ctl_card_info_get_mixername (const snd_ctl_card_info_t *obj)
| Get card mixer name from a CTL card info. More...
const char * | snd_ctl_card_info_get_components (const snd_ctl_card_info_t *obj)
| Get card component list from a CTL card info. More...
size_t | snd_ctl_event_sizeof (void)
| get size of snd_ctl_event_t More...
int | snd_ctl_event_malloc (snd_ctl_event_t **ptr)
| allocate an invalid snd_ctl_event_t using standard malloc More...
void | snd_ctl_event_free (snd_ctl_event_t *obj)
| frees a previously allocated snd_ctl_event_t More...
void | snd_ctl_event_clear (snd_ctl_event_t *obj)
| clear given snd_ctl_event_t object More...
void | snd_ctl_event_copy (snd_ctl_event_t *dst, const snd_ctl_event_t *src)
| copy one snd_ctl_event_t to another More...
snd_ctl_event_type_t | snd_ctl_event_get_type (const snd_ctl_event_t *obj)
| Get type of a CTL event. More...
size_t | snd_ctl_elem_list_sizeof (void)
| get size of snd_ctl_elem_list_t More...
int | snd_ctl_elem_list_malloc (snd_ctl_elem_list_t **ptr)
| allocate an invalid snd_ctl_elem_list_t using standard malloc More...
void | snd_ctl_elem_list_free (snd_ctl_elem_list_t *obj)
| frees a previously allocated snd_ctl_elem_list_t More...
void | snd_ctl_elem_list_clear (snd_ctl_elem_list_t *obj)
| clear given snd_ctl_elem_list_t object More...
void | snd_ctl_elem_list_copy (snd_ctl_elem_list_t *dst, const snd_ctl_elem_list_t *src)
| copy one snd_ctl_elem_list_t to another More...
void | snd_ctl_elem_list_set_offset (snd_ctl_elem_list_t *obj, unsigned int val)
| Set index of first wanted CTL element identifier in a CTL element identifiers list. More...
unsigned int | snd_ctl_elem_list_get_used (const snd_ctl_elem_list_t *obj)
| Get number of used entries in CTL element identifiers list. More...
unsigned int | snd_ctl_elem_list_get_count (const snd_ctl_elem_list_t *obj)
| Get total count of elements present in CTL device (information present in every filled CTL element identifiers list) More...
void | snd_ctl_elem_list_get_id (const snd_ctl_elem_list_t *obj, unsigned int idx, snd_ctl_elem_id_t *ptr)
| Get CTL element identifier for an entry of a CTL element identifiers list. More...
unsigned int | snd_ctl_elem_list_get_numid (const snd_ctl_elem_list_t *obj, unsigned int idx)
| Get CTL element numeric identifier for an entry of a CTL element identifiers list. More...
snd_ctl_elem_iface_t | snd_ctl_elem_list_get_interface (const snd_ctl_elem_list_t *obj, unsigned int idx)
| Get interface part of CTL element identifier for an entry of a CTL element identifiers list. More...
unsigned int | snd_ctl_elem_list_get_device (const snd_ctl_elem_list_t *obj, unsigned int idx)
| Get device part of CTL element identifier for an entry of a CTL element identifiers list. More...
unsigned int | snd_ctl_elem_list_get_subdevice (const snd_ctl_elem_list_t *obj, unsigned int idx)
| Get subdevice part of CTL element identifier for an entry of a CTL element identifiers list. More...
const char * | snd_ctl_elem_list_get_name (const snd_ctl_elem_list_t *obj, unsigned int idx)
| Get name part of CTL element identifier for an entry of a CTL element identifiers list. More...
unsigned int | snd_ctl_elem_list_get_index (const snd_ctl_elem_list_t *obj, unsigned int idx)
| Get index part of CTL element identifier for an entry of a CTL element identifiers list. More...
size_t | snd_ctl_elem_info_sizeof (void)
| get size of snd_ctl_elem_info_t More...
int | snd_ctl_elem_info_malloc (snd_ctl_elem_info_t **ptr)
| allocate an invalid snd_ctl_elem_info_t using standard malloc More...
void | snd_ctl_elem_info_free (snd_ctl_elem_info_t *obj)
| frees a previously allocated snd_ctl_elem_info_t More...
void | snd_ctl_elem_info_clear (snd_ctl_elem_info_t *obj)
| clear given snd_ctl_elem_info_t object More...
void | snd_ctl_elem_info_copy (snd_ctl_elem_info_t *dst, const snd_ctl_elem_info_t *src)
| copy one snd_ctl_elem_info_t to another More...
snd_ctl_elem_type_t | snd_ctl_elem_info_get_type (const snd_ctl_elem_info_t *obj)
| Get type from a CTL element id/info. More...
int | snd_ctl_elem_info_is_readable (const snd_ctl_elem_info_t *obj)
| Get info about readability from a CTL element id/info. More...
int | snd_ctl_elem_info_is_writable (const snd_ctl_elem_info_t *obj)
| Get info about writability from a CTL element id/info. More...
int | snd_ctl_elem_info_is_volatile (const snd_ctl_elem_info_t *obj)
| Get info about notification feasibility from a CTL element id/info. More...
int | snd_ctl_elem_info_is_inactive (const snd_ctl_elem_info_t *obj)
| Get info about status from a CTL element id/info. More...
int | snd_ctl_elem_info_is_locked (const snd_ctl_elem_info_t *obj)
| Get info whether an element is locked. More...
int | snd_ctl_elem_info_is_tlv_readable (const snd_ctl_elem_info_t *obj)
| Get info about TLV readability from a CTL element id/info. More...
int | snd_ctl_elem_info_is_tlv_writable (const snd_ctl_elem_info_t *obj)
| Get info about TLV writeability from a CTL element id/info. More...
int | snd_ctl_elem_info_is_tlv_commandable (const snd_ctl_elem_info_t *obj)
| Get info about TLV command possibility from a CTL element id/info. More...
int | snd_ctl_elem_info_is_owner (const snd_ctl_elem_info_t *obj)
| Get info if I own an element. More...
int | snd_ctl_elem_info_is_user (const snd_ctl_elem_info_t *obj)
| Get info if it's a user element. More...
pid_t | snd_ctl_elem_info_get_owner (const snd_ctl_elem_info_t *obj)
| Get owner of a locked element. More...
unsigned int | snd_ctl_elem_info_get_count (const snd_ctl_elem_info_t *obj)
| Get number of value entries from a CTL element id/info. More...
long | snd_ctl_elem_info_get_min (const snd_ctl_elem_info_t *obj)
| Get minimum value from a SND_CTL_ELEM_TYPE_INTEGER CTL element id/info. More...
long | snd_ctl_elem_info_get_max (const snd_ctl_elem_info_t *obj)
| Get maximum value from a SND_CTL_ELEM_TYPE_INTEGER CTL element id/info. More...
long | snd_ctl_elem_info_get_step (const snd_ctl_elem_info_t *obj)
| Get value step from a SND_CTL_ELEM_TYPE_INTEGER CTL element id/info. More...
long long | snd_ctl_elem_info_get_min64 (const snd_ctl_elem_info_t *obj)
| Get minimum value from a SND_CTL_ELEM_TYPE_INTEGER64 CTL element id/info. More...
long long | snd_ctl_elem_info_get_max64 (const snd_ctl_elem_info_t *obj)
| Get maximum value from a SND_CTL_ELEM_TYPE_INTEGER64 CTL element id/info. More...
long long | snd_ctl_elem_info_get_step64 (const snd_ctl_elem_info_t *obj)
| Get value step from a SND_CTL_ELEM_TYPE_INTEGER64 CTL element id/info. More...
unsigned int | snd_ctl_elem_info_get_items (const snd_ctl_elem_info_t *obj)
| Get number of items available from a SND_CTL_ELEM_TYPE_ENUMERATED CTL element id/info. More...
void | snd_ctl_elem_info_set_item (snd_ctl_elem_info_t *obj, unsigned int val)
| Select item in a SND_CTL_ELEM_TYPE_ENUMERATED CTL element id/info. More...
const char * | snd_ctl_elem_info_get_item_name (const snd_ctl_elem_info_t *obj)
| Get name for selected item in a SND_CTL_ELEM_TYPE_ENUMERATED CTL element id/info. More...
int | snd_ctl_elem_info_get_dimensions (const snd_ctl_elem_info_t *obj)
| Get count of dimensions for given element. More...
int | snd_ctl_elem_info_get_dimension (const snd_ctl_elem_info_t *obj, unsigned int idx)
| Get specified of dimension width for given element. More...
int | snd_ctl_elem_info_set_dimension (snd_ctl_elem_info_t *info, const int dimension[4])
| Set width to a specified dimension level of given element information. More...
void | snd_ctl_elem_info_get_id (const snd_ctl_elem_info_t *obj, snd_ctl_elem_id_t *ptr)
| Get CTL element identifier of a CTL element id/info. More...
unsigned int | snd_ctl_elem_info_get_numid (const snd_ctl_elem_info_t *obj)
| Get element numeric identifier of a CTL element id/info. More...
snd_ctl_elem_iface_t | snd_ctl_elem_info_get_interface (const snd_ctl_elem_info_t *obj)
| Get interface part of CTL element identifier of a CTL element id/info. More...
unsigned int | snd_ctl_elem_info_get_device (const snd_ctl_elem_info_t *obj)
| Get device part of CTL element identifier of a CTL element id/info. More...
unsigned int | snd_ctl_elem_info_get_subdevice (const snd_ctl_elem_info_t *obj)
| Get subdevice part of CTL element identifier of a CTL element id/info. More...
const char * | snd_ctl_elem_info_get_name (const snd_ctl_elem_info_t *obj)
| Get name part of CTL element identifier of a CTL element id/info. More...
unsigned int | snd_ctl_elem_info_get_index (const snd_ctl_elem_info_t *obj)
| Get index part of CTL element identifier of a CTL element id/info. More...
void | snd_ctl_elem_info_set_id (snd_ctl_elem_info_t *obj, const snd_ctl_elem_id_t *ptr)
| Set CTL element identifier of a CTL element id/info. More...
void | snd_ctl_elem_info_set_numid (snd_ctl_elem_info_t *obj, unsigned int val)
| Set element numeric identifier of a CTL element id/info. More...
void | snd_ctl_elem_info_set_interface (snd_ctl_elem_info_t *obj, snd_ctl_elem_iface_t val)
| Set interface part of CTL element identifier of a CTL element id/info. More...
void | snd_ctl_elem_info_set_device (snd_ctl_elem_info_t *obj, unsigned int val)
| Set device part of CTL element identifier of a CTL element id/info. More...
void | snd_ctl_elem_info_set_subdevice (snd_ctl_elem_info_t *obj, unsigned int val)
| Set subdevice part of CTL element identifier of a CTL element id/info. More...
void | snd_ctl_elem_info_set_name (snd_ctl_elem_info_t *obj, const char *val)
| Set name part of CTL element identifier of a CTL element id/info. More...
void | snd_ctl_elem_info_set_index (snd_ctl_elem_info_t *obj, unsigned int val)
| Set index part of CTL element identifier of a CTL element id/info. More...
int | snd_ctl_add_integer_elem_set (snd_ctl_t *ctl, snd_ctl_elem_info_t *info, unsigned int element_count, unsigned int member_count, long min, long max, long step)
| Create and add some user-defined control elements of integer type. More...
int | snd_ctl_add_integer64_elem_set (snd_ctl_t *ctl, snd_ctl_elem_info_t *info, unsigned int element_count, unsigned int member_count, long long min, long long max, long long step)
| Create and add some user-defined control elements of integer64 type. More...
int | snd_ctl_add_boolean_elem_set (snd_ctl_t *ctl, snd_ctl_elem_info_t *info, unsigned int element_count, unsigned int member_count)
| Create and add some user-defined control elements of boolean type. More...
int | snd_ctl_add_enumerated_elem_set (snd_ctl_t *ctl, snd_ctl_elem_info_t *info, unsigned int element_count, unsigned int member_count, unsigned int items, const char *const labels[])
| Create and add some user-defined control elements of enumerated type. More...
int | snd_ctl_add_bytes_elem_set (snd_ctl_t *ctl, snd_ctl_elem_info_t *info, unsigned int element_count, unsigned int member_count)
| Create and add some user-defined control elements of bytes type. More...
int | snd_ctl_elem_add_integer (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, unsigned int count, long imin, long imax, long istep)
| Create and add an user-defined control element of integer type. More...
int | snd_ctl_elem_add_integer64 (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, unsigned int count, long long imin, long long imax, long long istep)
| Create and add an user-defined control element of integer64 type. More...
int | snd_ctl_elem_add_boolean (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, unsigned int count)
| Create and add an user-defined control element of boolean type. More...
int | snd_ctl_elem_add_enumerated (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, unsigned int count, unsigned int items, const char *const names[])
| Create and add a user-defined control element of enumerated type. More...
int | snd_ctl_elem_add_iec958 (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id)
| Create and add a user-defined control element of IEC958 type. More...
int | snd_ctl_elem_remove (snd_ctl_t *ctl, snd_ctl_elem_id_t *id)
| Remove an user CTL element. More...
size_t | snd_ctl_elem_value_sizeof (void)
| Get size of data structure for an element. More...
int | snd_ctl_elem_value_malloc (snd_ctl_elem_value_t **ptr)
| Allocate an invalid snd_ctl_elem_value_t using standard malloc(3). More...
void | snd_ctl_elem_value_free (snd_ctl_elem_value_t *obj)
| Frees a previously allocated data of an element. More...
void | snd_ctl_elem_value_clear (snd_ctl_elem_value_t *obj)
| Clear given data of an element. More...
void | snd_ctl_elem_value_copy (snd_ctl_elem_value_t *dst, const snd_ctl_elem_value_t *src)
| Copy two data of elements. More...
int | snd_ctl_elem_value_compare (snd_ctl_elem_value_t *left, const snd_ctl_elem_value_t *right)
| Compare one data of an element to the other. More...
void | snd_ctl_elem_value_get_id (const snd_ctl_elem_value_t *obj, snd_ctl_elem_id_t *ptr)
| Get element identifier from given data of an element. More...
unsigned int | snd_ctl_elem_value_get_numid (const snd_ctl_elem_value_t *obj)
| Get element numeric identifier from given data of an element. More...
snd_ctl_elem_iface_t | snd_ctl_elem_value_get_interface (const snd_ctl_elem_value_t *obj)
| Get interface part of element identifier from given data of an element. More...
unsigned int | snd_ctl_elem_value_get_device (const snd_ctl_elem_value_t *obj)
| Get device part of element identifier from given data of an element. More...
unsigned int | snd_ctl_elem_value_get_subdevice (const snd_ctl_elem_value_t *obj)
| Get subdevice part of element identifier from given data of an element. More...
const char * | snd_ctl_elem_value_get_name (const snd_ctl_elem_value_t *obj)
| Get name part of element identifier from given data of an element. More...
unsigned int | snd_ctl_elem_value_get_index (const snd_ctl_elem_value_t *obj)
| Get index part of element identifier from given data of an element. More...
void | snd_ctl_elem_value_set_id (snd_ctl_elem_value_t *obj, const snd_ctl_elem_id_t *ptr)
| Set element identifier to given data of an element. More...
void | snd_ctl_elem_value_set_numid (snd_ctl_elem_value_t *obj, unsigned int val)
| Set numeric identifier to given data of an element. More...
void | snd_ctl_elem_value_set_interface (snd_ctl_elem_value_t *obj, snd_ctl_elem_iface_t val)
| Set interface part of element identifier to given data of an element. More...
void | snd_ctl_elem_value_set_device (snd_ctl_elem_value_t *obj, unsigned int val)
| Set device part of element identifier to given data of an element. More...
void | snd_ctl_elem_value_set_subdevice (snd_ctl_elem_value_t *obj, unsigned int val)
| Set subdevice part of element identifier to given data of an element. More...
void | snd_ctl_elem_value_set_name (snd_ctl_elem_value_t *obj, const char *val)
| Set name part of element identifier to given data of an element. More...
void | snd_ctl_elem_value_set_index (snd_ctl_elem_value_t *obj, unsigned int val)
| Set index part of element identifier to given data of an element. More...
int | snd_ctl_elem_value_get_boolean (const snd_ctl_elem_value_t *obj, unsigned int idx)
| Get value of a specified member from given data as an element of boolean type. More...
long | snd_ctl_elem_value_get_integer (const snd_ctl_elem_value_t *obj, unsigned int idx)
| Get value of a specified member from given data as an element of integer type. More...
long long | snd_ctl_elem_value_get_integer64 (const snd_ctl_elem_value_t *obj, unsigned int idx)
| Get value of a specified member from given data as an element of integer64 type. More...
unsigned int | snd_ctl_elem_value_get_enumerated (const snd_ctl_elem_value_t *obj, unsigned int idx)
| Get value of a specified member from given data as an element of enumerated type. More...
unsigned char | snd_ctl_elem_value_get_byte (const snd_ctl_elem_value_t *obj, unsigned int idx)
| Get value of a specified member from given data as an element of bytes type. More...
void | snd_ctl_elem_value_set_boolean (snd_ctl_elem_value_t *obj, unsigned int idx, long val)
| Set value of a specified member to given data as an element of boolean type. More...
void | snd_ctl_elem_value_set_integer (snd_ctl_elem_value_t *obj, unsigned int idx, long val)
| Set value of a specified member to given data as an element of integer type. More...
void | snd_ctl_elem_value_set_integer64 (snd_ctl_elem_value_t *obj, unsigned int idx, long long val)
| Set value of a specified member to given data as an element of integer64 type. More...
void | snd_ctl_elem_value_set_enumerated (snd_ctl_elem_value_t *obj, unsigned int idx, unsigned int val)
| Set value of a specified member to given data as an element of enumerated type. More...
void | snd_ctl_elem_value_set_byte (snd_ctl_elem_value_t *obj, unsigned int idx, unsigned char val)
| Set value for a specified member to given data as an element of byte type. More...
void | snd_ctl_elem_set_bytes (snd_ctl_elem_value_t *obj, void *data, size_t size)
| Set values to given data as an element of bytes type. More...
const void * | snd_ctl_elem_value_get_bytes (const snd_ctl_elem_value_t *obj)
| Get memory block from given data as an element of bytes type. More...
void | snd_ctl_elem_value_get_iec958 (const snd_ctl_elem_value_t *obj, snd_aes_iec958_t *ptr)
| Get value from given data to given pointer as an element of IEC958 type. More...
void | snd_ctl_elem_value_set_iec958 (snd_ctl_elem_value_t *obj, const snd_aes_iec958_t *ptr)
| Set value from given pointer to given data as an element of IEC958 type. More...
int | snd_tlv_parse_dB_info (unsigned int *tlv, unsigned int tlv_size, unsigned int **db_tlvp)
| Parse TLV stream and retrieve dB information. More...
int | snd_tlv_get_dB_range (unsigned int *tlv, long rangemin, long rangemax, long *min, long *max)
| Get the dB min/max values. More...
int | snd_tlv_convert_to_dB (unsigned int *tlv, long rangemin, long rangemax, long volume, long *db_gain)
| Convert the given raw volume value to a dB gain. More...
int | snd_tlv_convert_from_dB (unsigned int *tlv, long rangemin, long rangemax, long db_gain, long *value, int xdir)
| Convert from dB gain to the corresponding raw value. More...
int | snd_ctl_get_dB_range (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, long *min, long *max)
| Get the dB min/max values on the given control element. More...
int | snd_ctl_convert_to_dB (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, long volume, long *db_gain)
| Convert the volume value to dB on the given control element. More...
int | snd_ctl_convert_from_dB (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, long db_gain, long *value, int xdir)
| Convert from dB gain to the raw volume value on the given control element. More...

## Detailed Description

The control interface. See Control interface page for more details.

## Macro Definition Documentation

#define SND_CONTROL_DLSYM_VERSION _dlsym_control_001

dlsym version for interface entry callback

#define SND_CTL_ASYNC

Async notification (flag for open mode)

#define snd_ctl_card_info_alloca | ( |  | ptr | ) |

allocate an invalid snd_ctl_card_info_t using standard alloca

Parameters

  ptr | returned pointer

#define snd_ctl_elem_id_alloca | ( |  | ptr | ) |

allocate an invalid snd_ctl_elem_id_t using standard alloca

Parameters

  ptr | returned pointer

#define snd_ctl_elem_info_alloca | ( |  | ptr | ) |

allocate an invalid snd_ctl_elem_info_t using standard alloca

Parameters

  ptr | returned pointer

#define snd_ctl_elem_list_alloca | ( |  | ptr | ) |

allocate an invalid snd_ctl_elem_list_t using standard alloca

Parameters

  ptr | returned pointer

#define snd_ctl_elem_value_alloca | ( |  | ptr | ) |

allocate an invalid snd_ctl_elem_value_t using standard alloca

Parameters

  ptr | returned pointer

#define snd_ctl_event_alloca | ( |  | ptr | ) |

allocate an invalid snd_ctl_event_t using standard alloca

Parameters

  ptr | returned pointer

#define SND_CTL_EVENT_MASK_ADD

Element has been added

#define SND_CTL_EVENT_MASK_INFO

Element info has been changed

#define SND_CTL_EVENT_MASK_REMOVE

Element has been removed (Warning: test this first and if set don't test the other masks)

#define SND_CTL_EVENT_MASK_TLV

Element's TLV value has been changed

#define SND_CTL_EVENT_MASK_VALUE

Element value has been changed

#define SND_CTL_NAME_CAPTURE "Capture "

CTL name helper

#define SND_CTL_NAME_IEC958 | ( |  | expl,
|  |  | direction,
|  |  | what
| ) |  | "IEC958 " expl SND_CTL_NAME_##direction SND_CTL_NAME_IEC958_##what

Element name for IEC958 (S/PDIF)

#define SND_CTL_NAME_IEC958_CON_MASK "Con Mask"

CTL name helper

#define SND_CTL_NAME_IEC958_DEFAULT "Default"

CTL name helper

#define SND_CTL_NAME_IEC958_MASK "Mask"

CTL name helper

#define SND_CTL_NAME_IEC958_NONE ""

CTL name helper

#define SND_CTL_NAME_IEC958_PCM_STREAM "PCM Stream"

CTL name helper

#define SND_CTL_NAME_IEC958_PRO_MASK "Pro Mask"

CTL name helper

#define SND_CTL_NAME_IEC958_SWITCH "Switch"

CTL name helper

#define SND_CTL_NAME_IEC958_VOLUME "Volume"

CTL name helper

#define SND_CTL_NAME_NONE ""

CTL name helper

#define SND_CTL_NAME_PLAYBACK "Playback "

CTL name helper

#define SND_CTL_NONBLOCK

Non blocking mode (flag for open mode)

#define SND_CTL_POWER_D0 0x0000

ACPI/PCI Power State D0

#define SND_CTL_POWER_D1 0x0100

ACPI/PCI Power State D1

#define SND_CTL_POWER_D2 0x0200

ACPI/PCI Power State D2

#define SND_CTL_POWER_D3 0x0300

ACPI/PCI Power State D3

#define SND_CTL_POWER_D3cold (SND_CTL_POWER_D3|0x0001)

ACPI/PCI Power State D3cold

#define SND_CTL_POWER_D3hot (SND_CTL_POWER_D3|0x0000)

ACPI/PCI Power State D3hot

#define SND_CTL_POWER_MASK 0xff00

Mask for the major Power State identifier

#define SND_CTL_READONLY

Read only (flag for open mode)

#define SND_CTL_TLV_DB_GAIN_MUTE -9999999

Mute state

#define SND_CTL_TLVT_CHMAP_FIXED 0x00101

TLV type - fixed channel map positions

#define SND_CTL_TLVT_CHMAP_PAIRED 0x00103

TLV type - pair-wise swappable channel map positions

#define SND_CTL_TLVT_CHMAP_VAR 0x00102

TLV type - freely swappable channel map positions

#define SND_CTL_TLVT_CONTAINER 0x0000

TLV type - Container

#define SND_CTL_TLVT_DB_LINEAR 0x0002

TLV type - linear volume

#define SND_CTL_TLVT_DB_MINMAX 0x0004

TLV type - dB scale specified by min/max values

#define SND_CTL_TLVT_DB_MINMAX_MUTE 0x0005

TLV type - dB scale specified by min/max values (with mute)

#define SND_CTL_TLVT_DB_RANGE 0x0003

TLV type - dB range container

#define SND_CTL_TLVT_DB_SCALE 0x0001

TLV type - basic dB scale

#define SND_SCTL_NOFREE 0x0001

Don't destroy the ctl handle when close

## Typedef Documentation

typedef struct _snd_ctl_card_info snd_ctl_card_info_t

CTL card info container

typedef struct _snd_ctl_elem_id snd_ctl_elem_id_t

CTL element identifier container

typedef struct _snd_ctl_elem_info snd_ctl_elem_info_t

CTL element info container

typedef struct _snd_ctl_elem_list snd_ctl_elem_list_t

CTL element identifier list container

typedef struct _snd_ctl_elem_value snd_ctl_elem_value_t

CTL element value container

typedef struct _snd_ctl_event snd_ctl_event_t

CTL event container

typedef struct _snd_ctl snd_ctl_t

CTL handle

typedef struct _snd_sctl snd_sctl_t

SCTL type

## Enumeration Type Documentation

enum snd_ctl_elem_iface_t

CTL related interface

Enumerator
SND_CTL_ELEM_IFACE_CARD | Card level
SND_CTL_ELEM_IFACE_HWDEP | Hardware dependent device
SND_CTL_ELEM_IFACE_MIXER | Mixer
SND_CTL_ELEM_IFACE_PCM | PCM
SND_CTL_ELEM_IFACE_RAWMIDI | RawMidi
SND_CTL_ELEM_IFACE_TIMER | Timer
SND_CTL_ELEM_IFACE_SEQUENCER | Sequencer

enum snd_ctl_elem_type_t

CTL element type

Enumerator
SND_CTL_ELEM_TYPE_NONE | Invalid type
SND_CTL_ELEM_TYPE_BOOLEAN | Boolean contents
SND_CTL_ELEM_TYPE_INTEGER | Integer contents
SND_CTL_ELEM_TYPE_ENUMERATED | Enumerated contents
SND_CTL_ELEM_TYPE_BYTES | Bytes contents
SND_CTL_ELEM_TYPE_IEC958 | IEC958 (S/PDIF) setting content
SND_CTL_ELEM_TYPE_INTEGER64 | 64-bit integer contents

enum snd_ctl_event_type_t

Event class

Enumerator
SND_CTL_EVENT_ELEM | Elements related event

enum snd_ctl_type_t

CTL type

Enumerator
SND_CTL_TYPE_HW | Kernel level CTL
SND_CTL_TYPE_SHM | Shared memory client CTL
SND_CTL_TYPE_INET | INET client CTL (not yet implemented)
SND_CTL_TYPE_EXT | External control plugin

## Function Documentation

int snd_async_add_ctl_handler | ( | snd_async_handler_t ** | handler,
|  | snd_ctl_t * | ctl,
|  | snd_async_callback_t | callback,
|  | void * | private_data
| ) |  |

Add an async handler for a CTL.

Parameters

  handler | Returned handler handle
  ctl | CTL handle
  callback | Callback function
  private_data | Callback private data

Returns
  0 otherwise a negative error code on failure

snd_ctl_t* snd_async_handler_get_ctl | ( | snd_async_handler_t * | handler | ) |

Return CTL handle related to an async handler.

Parameters

  handler | Async handler handle

Returns
  CTL handle

int snd_card_get_index | ( | const char * | string | ) |

Convert card string to an integer value.

Parameters

  string | String containing card identifier

Returns
  zero if success, otherwise a negative error code

The accepted format is an integer value in ASCII representation or the card identifier (the id parameter for sound-card drivers). The control device name like /dev/snd/controlC0 is accepted, too.

int snd_card_get_longname | ( | int | card,
|  | char ** | name
| ) |  |

Obtain the card long name.

Parameters

  card | Card number
  name | Result - card long name corresponding to card number

Returns
  zero if success, otherwise a negative error code

The value returned in name is allocated with strdup and should be freed when no longer used.

int snd_card_get_name | ( | int | card,
|  | char ** | name
| ) |  |

Obtain the card name.

Parameters

  card | Card number
  name | Result - card name corresponding to card number

Returns
  zero if success, otherwise a negative error code

The value returned in name is allocated with strdup and should be freed when no longer used.

int snd_card_load | ( | int | card | ) |

Try to load the driver for a card.

Parameters

  card | Card number.

Returns
  1 if driver is present, zero if driver is not present

int snd_card_next | ( | int * | rcard | ) |

Try to determine the next card.

Parameters

  rcard | pointer to card number

Returns
  zero if success, otherwise a negative error code

Tries to determine the next card from given card number. If card number is -1, then the first available card is returned. If the result card number is -1, no more cards are available.

int snd_ctl_add_boolean_elem_set | ( | snd_ctl_t * | ctl,
|  | snd_ctl_elem_info_t * | info,
|  | unsigned int | element_count,
|  | unsigned int | member_count
| ) |  |

Create and add some user-defined control elements of boolean type.

Parameters

  ctl | A handle of backend module for control interface.
  info | Common iformation for a new element set, with ID of the first new element.
  element_count | The number of elements added by this operation.
  member_count | The number of members which a element has to represent its states.

This function creates some user elements with boolean type. These elements are not controlled by device drivers in kernel. They can be operated by the same way as usual elements added by the device drivers.

The name field of id must be set with unique value to identify new control elements. After returning, all fields of id are filled. A element can be identified by the combination of name and index, or by numid.

All of members in the new elements are locked. The value of each member is initialized with false.

Errors:
  -EBUSY
    A element with ID id already exists.
  -EINVAL
    Some parameters include invalid value; i.e. ID has no name, or the number of members is not between 1 to 127.
  -ENOMEM
    Out of memory, or there are too many user elements.
  -ENXIO
    This backend module does not support user elements of boolean type.
  -ENODEV
    Device unplugged.

Compatibility:
  This function is added in version 1.1.2.

int snd_ctl_add_bytes_elem_set | ( | snd_ctl_t * | ctl,
|  | snd_ctl_elem_info_t * | info,
|  | unsigned int | element_count,
|  | unsigned int | member_count
| ) |  |

Create and add some user-defined control elements of bytes type.

Parameters

  ctl | A handle of backend module for control interface.
  info | Common iformation for a new element set, with ID of the first new element.
  element_count | The number of elements added by this operation.
  member_count | The number of members which a element has to represent its states.

Returns
  Zero on success, otherwise a negative error code.

This function creates some user elements with bytes type. These elements are not controlled by device drivers in kernel. They can be operated by the same way as usual elements added by the device drivers.

The name field of id must be set with unique value to identify new control elements. After returning, all fields of id are filled. A element can be identified by the combination of name and index, or by numid.

All of members in the new elements are locked. The value of each member is initialized with the minimum value.

Errors:
  -EBUSY
    A element with ID id already exists.
  -EINVAL
    Some arguments include invalid value; i.e. ID has no name, or the number of members is not between 1 to 511.
  -ENOMEM
    Out of memory, or there are too many user elements.
  -ENXIO
    This backend module does not support user elements of bytes type.
  -ENODEV
    Device unplugged.

Compatibility:
  This function is added in version 1.1.2.

int snd_ctl_add_enumerated_elem_set | ( | snd_ctl_t * | ctl,
|  | snd_ctl_elem_info_t * | info,
|  | unsigned int | element_count,
|  | unsigned int | member_count,
|  | unsigned int | items,
|  | const char *const | labels[]
| ) |  |

Create and add some user-defined control elements of enumerated type.

Parameters

  ctl | A handle of backend module for control interface.
  info | Common iformation for a new element set, with ID of the first new element.
  element_count | The number of elements added by this operation.
  member_count | The number of members which a element has to represent its states.
  items | Range of possible values (0 ... items - 1).
  labels | An array containing items strings.

Returns
  Zero on success, otherwise a negative error code.

This function creates some user elements with enumerated type. These elements are not controlled by device drivers in kernel. They can be operated by the same way as usual elements added by the device drivers.

The name field of id must be set with unique value to identify new control elements. After returning, all fields of id are filled. A element can be identified by the combination of name and index, or by numid.

All of members in the new elements are locked. The value of each member is initialized with the first entry of labels.

Errors:
  -EBUSY
    A control element with ID id already exists.
  -EINVAL
    Some arguments include invalid value; i.e. element_count is not between 1 to 127, or items is not at least one, or a string in labels is empty, or longer than 63 bytes, or total length of the labels requires more than 64 KiB storage.
  -ENOMEM
    Out of memory, or there are too many user control elements.
  -ENXIO
    This driver does not support (enumerated) user controls.
  -ENODEV
    Device unplugged.

Compatibility:
  This function is added in version 1.1.2.

int snd_ctl_add_integer64_elem_set | ( | snd_ctl_t * | ctl,
|  | snd_ctl_elem_info_t * | info,
|  | unsigned int | element_count,
|  | unsigned int | member_count,
|  | long long | min,
|  | long long | max,
|  | long long | step
| ) |  |

Create and add some user-defined control elements of integer64 type.

Parameters

  ctl | A handle of backend module for control interface.
  info | Common iformation for a new element set, with ID of the first new element.
  element_count | The number of elements added by this operation.
  member_count | The number of members which a element has to represent its states.
  min | Minimum value for each member of the elements.
  max | Maximum value for each member of the elements.
  step | The step of value for each member in the elements.

Returns
  Zero on success, otherwise a negative error code.

This function creates some user elements with integer64 type. These elements are not controlled by device drivers in kernel. They can be operated by the same way as usual elements added by the device drivers.

The name field of id must be set with unique value to identify new control elements. After returning, all fields of id are filled. A element can be identified by the combination of name and index, or by numid.

All of members in the new elements are locked. The value of each member is initialized with the minimum value.

Errors:
  -EBUSY
    A element with ID id already exists.
  -EINVAL
    Some arguments include invalid value; i.e. ID has no name, or the number of members is not between 1 to 127.
  -ENOMEM
    Out of memory, or there are too many user elements.
  -ENXIO
    This backend module does not support user elements of integer64 type.
  -ENODEV
    Device unplugged.

Compatibility:
  This function is added in version 1.1.2.

int snd_ctl_add_integer_elem_set | ( | snd_ctl_t * | ctl,
|  | snd_ctl_elem_info_t * | info,
|  | unsigned int | element_count,
|  | unsigned int | member_count,
|  | long | min,
|  | long | max,
|  | long | step
| ) |  |

Create and add some user-defined control elements of integer type.

Parameters

  ctl | A handle of backend module for control interface.
  info | Common iformation for a new element set, with ID of the first new element.
  element_count | The number of elements added by this operation.
  member_count | The number of members which a element has to represent its states.
  min | Minimum value for each member of the elements.
  max | Maximum value for each member of the elements.
  step | The step of value for each member in the elements.

Returns
  Zero on success, otherwise a negative error code.

This function creates some user elements with integer type. These elements are not controlled by device drivers in kernel. They can be operated by the same way as usual elements added by the device drivers.

The name field of id must be set with unique value to identify new control elements. After returning, all fields of id are filled. A element can be identified by the combination of name and index, or by numid.

All of members in the new elements are locked. The value of each member is initialized with the minimum value.

Errors:
  -EBUSY
    A element with ID id already exists.
  -EINVAL
    Some arguments include invalid value; i.e. ID field in info has no name, or the number of members is not between 1 to 127.
  -ENOMEM
    Out of memory, or there are too many user elements.
  -ENXIO
    This backend module does not support user elements of integer type.
  -ENODEV
    Device unplugged.

Compatibility:
  This function is added in version 1.1.2.

char* snd_ctl_ascii_elem_id_get | ( | snd_ctl_elem_id_t * | id | ) |

return ASCII CTL element identifier name

Parameters

  id | CTL identifier

Returns
  ascii identifier of CTL element

The string is allocated using strdup().

int snd_ctl_ascii_elem_id_parse | ( | snd_ctl_elem_id_t * | dst,
|  | const char * | str
| ) |  |

parse ASCII string as CTL element identifier

Parameters

  dst | destination CTL identifier
  str | source ASCII string

Returns
  zero on success, otherwise a negative error code

int snd_ctl_ascii_value_parse | ( | snd_ctl_t * | handle,
|  | snd_ctl_elem_value_t * | dst,
|  | snd_ctl_elem_info_t * | info,
|  | const char * | value
| ) |  |

parse ASCII string as CTL element value

Parameters

  handle | CTL handle
  dst | destination CTL element value
  info | CTL element info structure
  value | source ASCII string

Returns
  zero on success, otherwise a negative error code

Note: For toggle command, the dst must contain previous (current) state (do the snd_ctl_elem_read call to obtain it).

int snd_ctl_card_info | ( | snd_ctl_t * | ctl,
|  | snd_ctl_card_info_t * | info
| ) |  |

Get card related information.

Parameters

  ctl | CTL handle
  info | Card info pointer

Returns
  0 on success otherwise a negative error code

void snd_ctl_card_info_clear | ( | snd_ctl_card_info_t * | obj | ) |

clear given snd_ctl_card_info_t object

Parameters

  obj | pointer to object to clear

void snd_ctl_card_info_copy | ( | snd_ctl_card_info_t * | dst,
|  | const snd_ctl_card_info_t * | src
| ) |  |

copy one snd_ctl_card_info_t to another

Parameters

  dst | pointer to destination
  src | pointer to source

void snd_ctl_card_info_free | ( | snd_ctl_card_info_t * | obj | ) |

frees a previously allocated snd_ctl_card_info_t

Parameters

  obj | pointer to object to free

int snd_ctl_card_info_get_card | ( | const snd_ctl_card_info_t * | obj | ) |

Get card number from a CTL card info.

Parameters

  obj | CTL card info

Returns
  card number

const char* snd_ctl_card_info_get_components | ( | const snd_ctl_card_info_t * | obj | ) |

Get card component list from a CTL card info.

Parameters

  obj | CTL card info

Returns
  card mixer identifier

const char* snd_ctl_card_info_get_driver | ( | const snd_ctl_card_info_t * | obj | ) |

Get card driver name from a CTL card info.

Parameters

  obj | CTL card info

Returns
  card driver name

const char* snd_ctl_card_info_get_id | ( | const snd_ctl_card_info_t * | obj | ) |

Get card identifier from a CTL card info.

Parameters

  obj | CTL card info

Returns
  card identifier

const char* snd_ctl_card_info_get_longname | ( | const snd_ctl_card_info_t * | obj | ) |

Get card long name from a CTL card info.

Parameters

  obj | CTL card info

Returns
  card long name

const char* snd_ctl_card_info_get_mixername | ( | const snd_ctl_card_info_t * | obj | ) |

Get card mixer name from a CTL card info.

Parameters

  obj | CTL card info

Returns
  card mixer name

const char* snd_ctl_card_info_get_name | ( | const snd_ctl_card_info_t * | obj | ) |

Get card name from a CTL card info.

Parameters

  obj | CTL card info

Returns
  card name

int snd_ctl_card_info_malloc | ( | snd_ctl_card_info_t ** | ptr | ) |

allocate an invalid snd_ctl_card_info_t using standard malloc

Parameters

  ptr | returned pointer

Returns
  0 on success otherwise negative error code

size_t snd_ctl_card_info_sizeof | ( | void |  | ) |

get size of snd_ctl_card_info_t

Returns
  size in bytes

int snd_ctl_close | ( | snd_ctl_t * | ctl | ) |

close CTL handle

Parameters

  ctl | CTL handle

Returns
  0 on success otherwise a negative error code

Closes the specified CTL handle and frees all associated resources.

int snd_ctl_convert_from_dB | ( | snd_ctl_t * | ctl,
|  | const snd_ctl_elem_id_t * | id,
|  | long | db_gain,
|  | long * | value,
|  | int | xdir
| ) |  |

Convert from dB gain to the raw volume value on the given control element.

Parameters

  ctl | the control handler
  id | the element id
  db_gain | the dB gain to convert (in 0.01dB unit)
  value | the pointer to store the converted raw volume value
  xdir | the direction for round-up. The value is round up when this is positive.

Returns
  0 if successful, or a negative error code

int snd_ctl_convert_to_dB | ( | snd_ctl_t * | ctl,
|  | const snd_ctl_elem_id_t * | id,
|  | long | volume,
|  | long * | db_gain
| ) |  |

Convert the volume value to dB on the given control element.

Parameters

  ctl | the control handler
  id | the element id
  volume | the raw volume value to convert
  db_gain | the dB gain (in 0.01dB unit)

Returns
  0 if successful, or a negative error code

int snd_ctl_elem_add_boolean | ( | snd_ctl_t * | ctl,
|  | const snd_ctl_elem_id_t * | id,
|  | unsigned int | member_count
| ) |  |

Create and add an user-defined control element of boolean type.

This is a wrapper function to snd_ctl_add_boolean_elem_set() for a single control element. This doesn't fill the id data with full information, thus it's recommended to use snd_ctl_add_boolean_elem_set(), instead.

int snd_ctl_elem_add_enumerated | ( | snd_ctl_t * | ctl,
|  | const snd_ctl_elem_id_t * | id,
|  | unsigned int | member_count,
|  | unsigned int | items,
|  | const char *const | labels[]
| ) |  |

Create and add a user-defined control element of enumerated type.

This is a wrapper function to snd_ctl_add_enumerated_elem_set() for a single control element. This doesn't fill the id data with full information, thus it's recommended to use snd_ctl_add_enumerated_elem_set(), instead.

This function is added in version 1.0.25.

int snd_ctl_elem_add_iec958 | ( | snd_ctl_t * | ctl,
|  | const snd_ctl_elem_id_t * | id
| ) |  |

Create and add a user-defined control element of IEC958 type.

Parameters

  [in] | ctl | A handle of backend module for control interface.
  [in,out] | id | ID of the new control element.

This function creates an user element with IEC958 type. This element is not controlled by device drivers in kernel. It can be operated by the same way as usual elements added by the device drivers.

The name field of id must be set with unique value to identify a new control element. After returning, all fields of id are filled. A element can be identified by the combination of name and index, or by numid.

A member in the new element is locked and filled with zero.

Errors:
  -EBUSY
    A control element with ID id already exists.
  -EINVAL
    ID has no name.
  -ENOMEM
    Out of memory, or there are too many user elements.
  -ENXIO
    This backend module does not support user elements of IEC958 type.
  -ENODEV
    Device unplugged.

int snd_ctl_elem_add_integer | ( | snd_ctl_t * | ctl,
|  | const snd_ctl_elem_id_t * | id,
|  | unsigned int | member_count,
|  | long | min,
|  | long | max,
|  | long | step
| ) |  |

Create and add an user-defined control element of integer type.

This is a wrapper function to snd_ctl_add_integer_elem_set() for a control element. This doesn't fill the id data with full information, thus it's recommended to use snd_ctl_add_integer_elem_set(), instead.

int snd_ctl_elem_add_integer64 | ( | snd_ctl_t * | ctl,
|  | const snd_ctl_elem_id_t * | id,
|  | unsigned int | member_count,
|  | long long | min,
|  | long long | max,
|  | long long | step
| ) |  |

Create and add an user-defined control element of integer64 type.

This is a wrapper function to snd_ctl_add_integer64_elem_set() for a single control element. This doesn't fill the id data with full information, thus it's recommended to use snd_ctl_add_integer64_elem_set(), instead.

void snd_ctl_elem_id_clear | ( | snd_ctl_elem_id_t * | obj | ) |

clear given snd_ctl_elem_id_t object

Parameters

  obj | pointer to object to clear

void snd_ctl_elem_id_copy | ( | snd_ctl_elem_id_t * | dst,
|  | const snd_ctl_elem_id_t * | src
| ) |  |

copy one snd_ctl_elem_id_t to another

Parameters

  dst | pointer to destination
  src | pointer to source

void snd_ctl_elem_id_free | ( | snd_ctl_elem_id_t * | obj | ) |

frees a previously allocated snd_ctl_elem_id_t

Parameters

  obj | pointer to object to free

unsigned int snd_ctl_elem_id_get_device | ( | const snd_ctl_elem_id_t * | obj | ) |

Get device part of a CTL element identifier.

Parameters

  obj | CTL element identifier

Returns
  CTL element related device

unsigned int snd_ctl_elem_id_get_index | ( | const snd_ctl_elem_id_t * | obj | ) |

Get index part of a CTL element identifier.

Parameters

  obj | CTL element identifier

Returns
  CTL element index

snd_ctl_elem_iface_t snd_ctl_elem_id_get_interface | ( | const snd_ctl_elem_id_t * | obj | ) |

Get interface part of a CTL element identifier.

Parameters

  obj | CTL element identifier

Returns
  CTL element related interface

const char* snd_ctl_elem_id_get_name | ( | const snd_ctl_elem_id_t * | obj | ) |

Get name part of a CTL element identifier.

Parameters

  obj | CTL element identifier

Returns
  CTL element name

unsigned int snd_ctl_elem_id_get_numid | ( | const snd_ctl_elem_id_t * | obj | ) |

Get numeric identifier from a CTL element identifier.

Parameters

  obj | CTL element identifier

Returns
  CTL element numeric identifier

unsigned int snd_ctl_elem_id_get_subdevice | ( | const snd_ctl_elem_id_t * | obj | ) |

Get subdevice part of a CTL element identifier.

Parameters

  obj | CTL element identifier

Returns
  CTL element related subdevice

int snd_ctl_elem_id_malloc | ( | snd_ctl_elem_id_t ** | ptr | ) |

allocate an invalid snd_ctl_elem_id_t using standard malloc

Parameters

  ptr | returned pointer

Returns
  0 on success otherwise negative error code

void snd_ctl_elem_id_set_device | ( | snd_ctl_elem_id_t * | obj,
|  | unsigned int | val
| ) |  |

Set device part for a CTL element identifier.

Parameters

  obj | CTL element identifier
  val | CTL element related device

void snd_ctl_elem_id_set_index | ( | snd_ctl_elem_id_t * | obj,
|  | unsigned int | val
| ) |  |

Set index part for a CTL element identifier.

Parameters

  obj | CTL element identifier
  val | CTL element index

void snd_ctl_elem_id_set_interface | ( | snd_ctl_elem_id_t * | obj,
|  | snd_ctl_elem_iface_t | val
| ) |  |

Set interface part for a CTL element identifier.

Parameters

  obj | CTL element identifier
  val | CTL element related interface

void snd_ctl_elem_id_set_name | ( | snd_ctl_elem_id_t * | obj,
|  | const char * | val
| ) |  |

Set name part for a CTL element identifier.

Parameters

  obj | CTL element identifier
  val | CTL element name

void snd_ctl_elem_id_set_numid | ( | snd_ctl_elem_id_t * | obj,
|  | unsigned int | val
| ) |  |

Set numeric identifier for a CTL element identifier.

Parameters

  obj | CTL element identifier
  val | CTL element numeric identifier

void snd_ctl_elem_id_set_subdevice | ( | snd_ctl_elem_id_t * | obj,
|  | unsigned int | val
| ) |  |

Set subdevice part for a CTL element identifier.

Parameters

  obj | CTL element identifier
  val | CTL element related subdevice

size_t snd_ctl_elem_id_sizeof | ( | void |  | ) |

get size of snd_ctl_elem_id_t

Returns
  size in bytes

const char* snd_ctl_elem_iface_name | ( | snd_ctl_elem_iface_t | iface | ) |

get name of a CTL element related interface

Parameters

  iface | CTL element related interface

Returns
  ascii name of CTL element related interface

int snd_ctl_elem_info | ( | snd_ctl_t * | ctl,
|  | snd_ctl_elem_info_t * | info
| ) |  |

Get CTL element information.

Parameters

  ctl | CTL handle
  info | CTL element id/information pointer

Returns
  0 on success otherwise a negative error code

void snd_ctl_elem_info_clear | ( | snd_ctl_elem_info_t * | obj | ) |

clear given snd_ctl_elem_info_t object

Parameters

  obj | pointer to object to clear

void snd_ctl_elem_info_copy | ( | snd_ctl_elem_info_t * | dst,
|  | const snd_ctl_elem_info_t * | src
| ) |  |

copy one snd_ctl_elem_info_t to another

Parameters

  dst | pointer to destination
  src | pointer to source

void snd_ctl_elem_info_free | ( | snd_ctl_elem_info_t * | obj | ) |

frees a previously allocated snd_ctl_elem_info_t

Parameters

  obj | pointer to object to free

unsigned int snd_ctl_elem_info_get_count | ( | const snd_ctl_elem_info_t * | obj | ) |

Get number of value entries from a CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  value entries count

unsigned int snd_ctl_elem_info_get_device | ( | const snd_ctl_elem_info_t * | obj | ) |

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

Parameters

  obj | CTL element id/info

Returns
  device part of element identifier

int snd_ctl_elem_info_get_dimension | ( | const snd_ctl_elem_info_t * | obj,
|  | unsigned int | idx
| ) |  |

Get specified of dimension width for given element.

Parameters

  obj | CTL element id/info
  idx | The dimension index

Returns
  zero value if no dimension width is defined, otherwise positive value with with of specified dimension

Deprecated:
  Since 1.1.5 snd_ctl_elem_info_get_dimension is deprecated without any replacement.

int snd_ctl_elem_info_get_dimensions | ( | const snd_ctl_elem_info_t * | obj | ) |

Get count of dimensions for given element.

Parameters

  obj | CTL element id/info

Returns
  zero value if no dimensions are defined, otherwise positive value with count of dimensions

Deprecated:
  Since 1.1.5 snd_ctl_elem_info_get_dimensions is deprecated without any replacement.

void snd_ctl_elem_info_get_id | ( | const snd_ctl_elem_info_t * | obj,
|  | snd_ctl_elem_id_t * | ptr
| ) |  |

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

Parameters

  obj | CTL element id/info
  ptr | Pointer to returned CTL element identifier

unsigned int snd_ctl_elem_info_get_index | ( | const snd_ctl_elem_info_t * | obj | ) |

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

Parameters

  obj | CTL element id/info

Returns
  index part of element identifier

snd_ctl_elem_iface_t snd_ctl_elem_info_get_interface | ( | const snd_ctl_elem_info_t * | obj | ) |

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

Parameters

  obj | CTL element id/info

Returns
  interface part of element identifier

const char* snd_ctl_elem_info_get_item_name | ( | const snd_ctl_elem_info_t * | obj | ) |

Get name for selected item in a SND_CTL_ELEM_TYPE_ENUMERATED CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  name of chosen item

unsigned int snd_ctl_elem_info_get_items | ( | const snd_ctl_elem_info_t * | obj | ) |

Get number of items available from a SND_CTL_ELEM_TYPE_ENUMERATED CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  items count

long snd_ctl_elem_info_get_max | ( | const snd_ctl_elem_info_t * | obj | ) |

Get maximum value from a SND_CTL_ELEM_TYPE_INTEGER CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  Maximum value

long long snd_ctl_elem_info_get_max64 | ( | const snd_ctl_elem_info_t * | obj | ) |

Get maximum value from a SND_CTL_ELEM_TYPE_INTEGER64 CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  Maximum value

long snd_ctl_elem_info_get_min | ( | const snd_ctl_elem_info_t * | obj | ) |

Get minimum value from a SND_CTL_ELEM_TYPE_INTEGER CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  Minimum value

long long snd_ctl_elem_info_get_min64 | ( | const snd_ctl_elem_info_t * | obj | ) |

Get minimum value from a SND_CTL_ELEM_TYPE_INTEGER64 CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  Minimum value

const char* snd_ctl_elem_info_get_name | ( | const snd_ctl_elem_info_t * | obj | ) |

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

Parameters

  obj | CTL element id/info

Returns
  name part of element identifier

unsigned int snd_ctl_elem_info_get_numid | ( | const snd_ctl_elem_info_t * | obj | ) |

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

Parameters

  obj | CTL element id/info

Returns
  element numeric identifier

pid_t snd_ctl_elem_info_get_owner | ( | const snd_ctl_elem_info_t * | obj | ) |

Get owner of a locked element.

Parameters

  obj | CTL element id/info

Returns
  value entries count

long snd_ctl_elem_info_get_step | ( | const snd_ctl_elem_info_t * | obj | ) |

Get value step from a SND_CTL_ELEM_TYPE_INTEGER CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  Step

long long snd_ctl_elem_info_get_step64 | ( | const snd_ctl_elem_info_t * | obj | ) |

Get value step from a SND_CTL_ELEM_TYPE_INTEGER64 CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  Step

unsigned int snd_ctl_elem_info_get_subdevice | ( | const snd_ctl_elem_info_t * | obj | ) |

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

Parameters

  obj | CTL element id/info

Returns
  subdevice part of element identifier

snd_ctl_elem_type_t snd_ctl_elem_info_get_type | ( | const snd_ctl_elem_info_t * | obj | ) |

Get type from a CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  CTL element content type

int snd_ctl_elem_info_is_inactive | ( | const snd_ctl_elem_info_t * | obj | ) |

Get info about status from a CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  0 if element value is not active, 1 if is active

int snd_ctl_elem_info_is_locked | ( | const snd_ctl_elem_info_t * | obj | ) |

Get info whether an element is locked.

Parameters

  obj | CTL element id/info

Returns
  0 if element value is currently changeable, 1 if it's locked by another application

int snd_ctl_elem_info_is_owner | ( | const snd_ctl_elem_info_t * | obj | ) |

Get info if I own an element.

Parameters

  obj | CTL element id/info

Returns
  0 if element value is currently changeable, 1 if it's locked by another application

int snd_ctl_elem_info_is_readable | ( | const snd_ctl_elem_info_t * | obj | ) |

Get info about readability from a CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  0 if element is not readable, 1 if element is readable

int snd_ctl_elem_info_is_tlv_commandable | ( | const snd_ctl_elem_info_t * | obj | ) |

Get info about TLV command possibility from a CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  0 if element's TLV command is not possible, 1 if element's TLV command is supported

int snd_ctl_elem_info_is_tlv_readable | ( | const snd_ctl_elem_info_t * | obj | ) |

Get info about TLV readability from a CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  0 if element's TLV is not readable, 1 if element's TLV is readable

int snd_ctl_elem_info_is_tlv_writable | ( | const snd_ctl_elem_info_t * | obj | ) |

Get info about TLV writeability from a CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  0 if element's TLV is not writable, 1 if element's TLV is writable

int snd_ctl_elem_info_is_user | ( | const snd_ctl_elem_info_t * | obj | ) |

Get info if it's a user element.

Parameters

  obj | CTL element id/info

Returns
  0 if element value is a system element, 1 if it's a user-created element

int snd_ctl_elem_info_is_volatile | ( | const snd_ctl_elem_info_t * | obj | ) |

Get info about notification feasibility from a CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  0 if all element value changes are notified to subscribed applications, 1 otherwise

int snd_ctl_elem_info_is_writable | ( | const snd_ctl_elem_info_t * | obj | ) |

Get info about writability from a CTL element id/info.

Parameters

  obj | CTL element id/info

Returns
  0 if element is not writable, 1 if element is not writable

int snd_ctl_elem_info_malloc | ( | snd_ctl_elem_info_t ** | ptr | ) |

allocate an invalid snd_ctl_elem_info_t using standard malloc

Parameters

  ptr | returned pointer

Returns
  0 on success otherwise negative error code

void snd_ctl_elem_info_set_device | ( | snd_ctl_elem_info_t * | obj,
|  | unsigned int | val
| ) |  |

Set device part of CTL element identifier of a CTL element id/info.

Parameters

  obj | CTL element id/info
  val | device part of element identifier

int snd_ctl_elem_info_set_dimension | ( | snd_ctl_elem_info_t * | info,
|  | const int | dimension[4]
| ) |  |

Set width to a specified dimension level of given element information.

Parameters

  info | Information of an element.
  dimension | Dimension width for each level by member unit.

Returns
  Zero on success, otherwise a negative error code.

Errors:
  -EINVAL
    Invalid arguments are given as parameters.

Compatibility:
  This function is added in version 1.1.2.

Deprecated:
  Since 1.1.5 snd_ctl_elem_info_set_dimension is deprecated without any replacement.

void snd_ctl_elem_info_set_id | ( | snd_ctl_elem_info_t * | obj,
|  | const snd_ctl_elem_id_t * | ptr
| ) |  |

Set CTL element identifier of a CTL element id/info.

Parameters

  obj | CTL element id/info
  ptr | CTL element identifier

void snd_ctl_elem_info_set_index | ( | snd_ctl_elem_info_t * | obj,
|  | unsigned int | val
| ) |  |

Set index part of CTL element identifier of a CTL element id/info.

Parameters

  obj | CTL element id/info
  val | index part of element identifier

void snd_ctl_elem_info_set_interface | ( | snd_ctl_elem_info_t * | obj,
|  | snd_ctl_elem_iface_t | val
| ) |  |

Set interface part of CTL element identifier of a CTL element id/info.

Parameters

  obj | CTL element id/info
  val | interface part of element identifier

void snd_ctl_elem_info_set_item | ( | snd_ctl_elem_info_t * | obj,
|  | unsigned int | val
| ) |  |

Select item in a SND_CTL_ELEM_TYPE_ENUMERATED CTL element id/info.

Parameters

  obj | CTL element id/info
  val | item number

void snd_ctl_elem_info_set_name | ( | snd_ctl_elem_info_t * | obj,
|  | const char * | val
| ) |  |

Set name part of CTL element identifier of a CTL element id/info.

Parameters

  obj | CTL element id/info
  val | name part of element identifier

void snd_ctl_elem_info_set_numid | ( | snd_ctl_elem_info_t * | obj,
|  | unsigned int | val
| ) |  |

Set element numeric identifier of a CTL element id/info.

Parameters

  obj | CTL element id/info
  val | element numeric identifier

void snd_ctl_elem_info_set_subdevice | ( | snd_ctl_elem_info_t * | obj,
|  | unsigned int | val
| ) |  |

Set subdevice part of CTL element identifier of a CTL element id/info.

Parameters

  obj | CTL element id/info
  val | subdevice part of element identifier

size_t snd_ctl_elem_info_sizeof | ( | void |  | ) |

get size of snd_ctl_elem_info_t

Returns
  size in bytes

int snd_ctl_elem_list | ( | snd_ctl_t * | ctl,
|  | snd_ctl_elem_list_t * | list
| ) |  |

Get a list of element identifiers.

Parameters

  ctl | CTL handle
  list | CTL element identifiers list pointer

Returns
  0 on success otherwise a negative error code

int snd_ctl_elem_list_alloc_space | ( | snd_ctl_elem_list_t * | obj,
|  | unsigned int | entries
| ) |  |

allocate space for CTL element identifiers list

Parameters

  obj | CTL element identifiers list
  entries | Entries to allocate

Returns
  0 on success otherwise a negative error code

void snd_ctl_elem_list_clear | ( | snd_ctl_elem_list_t * | obj | ) |

clear given snd_ctl_elem_list_t object

Parameters

  obj | pointer to object to clear

void snd_ctl_elem_list_copy | ( | snd_ctl_elem_list_t * | dst,
|  | const snd_ctl_elem_list_t * | src
| ) |  |

copy one snd_ctl_elem_list_t to another

Parameters

  dst | pointer to destination
  src | pointer to source

void snd_ctl_elem_list_free | ( | snd_ctl_elem_list_t * | obj | ) |

frees a previously allocated snd_ctl_elem_list_t

Parameters

  obj | pointer to object to free

void snd_ctl_elem_list_free_space | ( | snd_ctl_elem_list_t * | obj | ) |

free previously allocated space for CTL element identifiers list

Parameters

  obj | CTL element identifiers list

unsigned int snd_ctl_elem_list_get_count | ( | const snd_ctl_elem_list_t * | obj | ) |

Get total count of elements present in CTL device (information present in every filled CTL element identifiers list)

Parameters

  obj | CTL element identifier list

Returns
  total number of elements

unsigned int snd_ctl_elem_list_get_device | ( | const snd_ctl_elem_list_t * | obj,
|  | unsigned int | idx
| ) |  |

Get device part of CTL element identifier for an entry of a CTL element identifiers list.

Parameters

  obj | CTL element identifier list
  idx | Index of entry

Returns
  CTL element related device

void snd_ctl_elem_list_get_id | ( | const snd_ctl_elem_list_t * | obj,
|  | unsigned int | idx,
|  | snd_ctl_elem_id_t * | ptr
| ) |  |

Get CTL element identifier for an entry of a CTL element identifiers list.

Parameters

  obj | CTL element identifier list
  idx | Index of entry
  ptr | Pointer to returned CTL element identifier

unsigned int snd_ctl_elem_list_get_index | ( | const snd_ctl_elem_list_t * | obj,
|  | unsigned int | idx
| ) |  |

Get index part of CTL element identifier for an entry of a CTL element identifiers list.

Parameters

  obj | CTL element identifier list
  idx | Index of entry

Returns
  CTL element index

snd_ctl_elem_iface_t snd_ctl_elem_list_get_interface | ( | const snd_ctl_elem_list_t * | obj,
|  | unsigned int | idx
| ) |  |

Get interface part of CTL element identifier for an entry of a CTL element identifiers list.

Parameters

  obj | CTL element identifier list
  idx | Index of entry

Returns
  CTL element related interface

const char* snd_ctl_elem_list_get_name | ( | const snd_ctl_elem_list_t * | obj,
|  | unsigned int | idx
| ) |  |

Get name part of CTL element identifier for an entry of a CTL element identifiers list.

Parameters

  obj | CTL element identifier list
  idx | Index of entry

Returns
  CTL element name

unsigned int snd_ctl_elem_list_get_numid | ( | const snd_ctl_elem_list_t * | obj,
|  | unsigned int | idx
| ) |  |

Get CTL element numeric identifier for an entry of a CTL element identifiers list.

Parameters

  obj | CTL element identifier list
  idx | Index of entry

Returns
  CTL element numeric identifier

unsigned int snd_ctl_elem_list_get_subdevice | ( | const snd_ctl_elem_list_t * | obj,
|  | unsigned int | idx
| ) |  |

Get subdevice part of CTL element identifier for an entry of a CTL element identifiers list.

Parameters

  obj | CTL element identifier list
  idx | Index of entry

Returns
  CTL element related subdevice

unsigned int snd_ctl_elem_list_get_used | ( | const snd_ctl_elem_list_t * | obj | ) |

Get number of used entries in CTL element identifiers list.

Parameters

  obj | CTL element identifier list

Returns
  number of used entries

int snd_ctl_elem_list_malloc | ( | snd_ctl_elem_list_t ** | ptr | ) |

allocate an invalid snd_ctl_elem_list_t using standard malloc

Parameters

  ptr | returned pointer

Returns
  0 on success otherwise negative error code

void snd_ctl_elem_list_set_offset | ( | snd_ctl_elem_list_t * | obj,
|  | unsigned int | val
| ) |  |

Set index of first wanted CTL element identifier in a CTL element identifiers list.

Parameters

  obj | CTL element identifiers list
  val | index of CTL element to put at position 0 of list

size_t snd_ctl_elem_list_sizeof | ( | void |  | ) |

get size of snd_ctl_elem_list_t

Returns
  size in bytes

int snd_ctl_elem_lock | ( | snd_ctl_t * | ctl,
|  | snd_ctl_elem_id_t * | id
| ) |  |

Lock CTL element.

Parameters

  ctl | CTL handle
  id | CTL element id pointer

Returns
  0 on success otherwise a negative error code

int snd_ctl_elem_read | ( | snd_ctl_t * | ctl,
|  | snd_ctl_elem_value_t * | data
| ) |  |

Get CTL element value.

Parameters

  ctl | CTL handle
  data | Data of an element.

Returns
  0 on success otherwise a negative error code

int snd_ctl_elem_remove | ( | snd_ctl_t * | ctl,
|  | snd_ctl_elem_id_t * | id
| ) |  |

Remove an user CTL element.

Parameters

  ctl | CTL handle
  id | CTL element identification

Returns
  0 on success otherwise a negative error code

void snd_ctl_elem_set_bytes | ( | snd_ctl_elem_value_t * | obj,
|  | void * | data,
|  | size_t | size
| ) |  |

Set values to given data as an element of bytes type.

Parameters

  obj | Data of an element.
  data | Pointer for byte array.
  size | The number of bytes included in the memory block.

int snd_ctl_elem_tlv_command | ( | snd_ctl_t * | ctl,
|  | const snd_ctl_elem_id_t * | id,
|  | const unsigned int * | tlv
| ) |  |

Process structured data from given buffer for an element set.

Parameters

  ctl | A handle of backend module for control interface.
  id | ID of an element.
  tlv | An array with members of unsigned int type. The second member must represent total bytes of the rest of array.

Return values

  0 | on success
  >0 | on success when value was changed
  <0 | a negative error code

The format of an array of tlv argument is: tlv[0]: Type. One of SND_CTL_TLVT_XXX. tlv[1]: Length. The length of value in units of byte. tlv[2..]: Value. Depending on the type.

Details are described in <sound/tlv.h>.

int snd_ctl_elem_tlv_read | ( | snd_ctl_t * | ctl,
|  | const snd_ctl_elem_id_t * | id,
|  | unsigned int * | tlv,
|  | unsigned int | tlv_size
| ) |  |

Read structured data from an element set to given buffer.

Parameters

  ctl | A handle of backend module for control interface.
  id | ID of an element.
  tlv | An array with members of unsigned int type.
  tlv_size | The length of the array.

Returns
  0 on success otherwise a negative error code

The format of an array of tlv argument is: tlv[0]: Type. One of SND_CTL_TLVT_XXX. tlv[1]: Length. The length of value in units of byte. tlv[2..]: Value. Depending on the type.

Details are described in <sound/tlv.h>.

int snd_ctl_elem_tlv_write | ( | snd_ctl_t * | ctl,
|  | const snd_ctl_elem_id_t * | id,
|  | const unsigned int * | tlv
| ) |  |

Write structured data from given buffer to an element set.

Parameters

  ctl | A handle of backend module for control interface.
  id | ID of an element.
  tlv | An array with members of unsigned int type. The second member must represent total bytes of the rest of array.

Return values

  0 | on success
  >0 | on success when value was changed
  <0 | a negative error code

The format of an array of tlv argument is: tlv[0]: Type. One of SND_CTL_TLVT_XXX. tlv[1]: Length. The length of value in units of byte. tlv[2..]: Value. Depending on the type.

Details are described in <sound/tlv.h>.

const char* snd_ctl_elem_type_name | ( | snd_ctl_elem_type_t | type | ) |

get name of a CTL element type

Parameters

  type | CTL element type

Returns
  ascii name of CTL element type

int snd_ctl_elem_unlock | ( | snd_ctl_t * | ctl,
|  | snd_ctl_elem_id_t * | id
| ) |  |

Unlock CTL element.

Parameters

  ctl | CTL handle
  id | CTL element id pointer

Returns
  0 on success otherwise a negative error code

void snd_ctl_elem_value_clear | ( | snd_ctl_elem_value_t * | obj | ) |

Clear given data of an element.

Parameters

  obj | Data of an element.

int snd_ctl_elem_value_compare | ( | snd_ctl_elem_value_t * | left,
|  | const snd_ctl_elem_value_t * | right
| ) |  |

Compare one data of an element to the other.

Parameters

  left | Pointer to first data.
  right | Pointer to second data.

Returns
  0 on match, less than or greater than otherwise, see memcmp(3).

void snd_ctl_elem_value_copy | ( | snd_ctl_elem_value_t * | dst,
|  | const snd_ctl_elem_value_t * | src
| ) |  |

Copy two data of elements.

Parameters

  dst | Pointer to destination.
  src | Pointer to source.

void snd_ctl_elem_value_free | ( | snd_ctl_elem_value_t * | obj | ) |

Frees a previously allocated data of an element.

Parameters

  obj | Data of an element.

int snd_ctl_elem_value_get_boolean | ( | const snd_ctl_elem_value_t * | obj,
|  | unsigned int | idx
| ) |  |

Get value of a specified member from given data as an element of boolean type.

Parameters

  obj | Data of an element.
  idx | Index of member in the element.

Returns
  Value for the member.

unsigned char snd_ctl_elem_value_get_byte | ( | const snd_ctl_elem_value_t * | obj,
|  | unsigned int | idx
| ) |  |

Get value of a specified member from given data as an element of bytes type.

Parameters

  obj | Data of an element.
  idx | Index of member in the element.

Returns
  Value for the member.

const void* snd_ctl_elem_value_get_bytes | ( | const snd_ctl_elem_value_t * | obj | ) |

Get memory block from given data as an element of bytes type.

Parameters

  obj | Data of an element.

Returns
  Pointer for byte array.

unsigned int snd_ctl_elem_value_get_device | ( | const snd_ctl_elem_value_t * | obj | ) |

Get device part of element identifier from given data of an element.

Parameters

  obj | Data of an element.

Returns
  Device part of element identifier.

unsigned int snd_ctl_elem_value_get_enumerated | ( | const snd_ctl_elem_value_t * | obj,
|  | unsigned int | idx
| ) |  |

Get value of a specified member from given data as an element of enumerated type.

Parameters

  obj | Data of an element.
  idx | Index of member in the element.

Returns
  Value for the member. This is an index of name set in the element.

void snd_ctl_elem_value_get_id | ( | const snd_ctl_elem_value_t * | obj,
|  | snd_ctl_elem_id_t * | ptr
| ) |  |

Get element identifier from given data of an element.

Parameters

  obj | Data of an element.
  ptr | Pointer for element identifier.

void snd_ctl_elem_value_get_iec958 | ( | const snd_ctl_elem_value_t * | obj,
|  | snd_aes_iec958_t * | ptr
| ) |  |

Get value from given data to given pointer as an element of IEC958 type.

Parameters

  obj | Data of an element.
  ptr | Pointer to IEC958 data.

unsigned int snd_ctl_elem_value_get_index | ( | const snd_ctl_elem_value_t * | obj | ) |

Get index part of element identifier from given data of an element.

Parameters

  obj | Data of an element.

Returns
  Index part of element identifier.

long snd_ctl_elem_value_get_integer | ( | const snd_ctl_elem_value_t * | obj,
|  | unsigned int | idx
| ) |  |

Get value of a specified member from given data as an element of integer type.

Parameters

  obj | Data of an element.
  idx | Index of member in the element.

Returns
  Value for the member.

long long snd_ctl_elem_value_get_integer64 | ( | const snd_ctl_elem_value_t * | obj,
|  | unsigned int | idx
| ) |  |

Get value of a specified member from given data as an element of integer64 type.

Parameters

  obj | Data of an element.
  idx | Index of member in the element.

Returns
  Value for the member.

snd_ctl_elem_iface_t snd_ctl_elem_value_get_interface | ( | const snd_ctl_elem_value_t * | obj | ) |

Get interface part of element identifier from given data of an element.

Parameters

  obj | Data of an element.

Returns
  Interface part of element identifier.

const char* snd_ctl_elem_value_get_name | ( | const snd_ctl_elem_value_t * | obj | ) |

Get name part of element identifier from given data of an element.

Parameters

  obj | Data of an element.

Returns
  Name part of element identifier.

unsigned int snd_ctl_elem_value_get_numid | ( | const snd_ctl_elem_value_t * | obj | ) |

Get element numeric identifier from given data of an element.

Parameters

  obj | Data of an element.

Returns
  Element numeric identifier.

unsigned int snd_ctl_elem_value_get_subdevice | ( | const snd_ctl_elem_value_t * | obj | ) |

Get subdevice part of element identifier from given data of an element.

Parameters

  obj | Data of an element.

Returns
  Subdevice part of element identifier.

int snd_ctl_elem_value_malloc | ( | snd_ctl_elem_value_t ** | ptr | ) |

Allocate an invalid snd_ctl_elem_value_t using standard malloc(3).

Parameters

  ptr | Returned pointer for data of an element.

Returns
  0 on success otherwise negative error code.

void snd_ctl_elem_value_set_boolean | ( | snd_ctl_elem_value_t * | obj,
|  | unsigned int | idx,
|  | long | val
| ) |  |

Set value of a specified member to given data as an element of boolean type.

Parameters

  obj | Data of an element.
  idx | Index of member in the element.
  val | Value for the member.

void snd_ctl_elem_value_set_byte | ( | snd_ctl_elem_value_t * | obj,
|  | unsigned int | idx,
|  | unsigned char | val
| ) |  |

Set value for a specified member to given data as an element of byte type.

Parameters

  obj | Data of an element.
  idx | Index of member in the element.
  val | Value for the member.

void snd_ctl_elem_value_set_device | ( | snd_ctl_elem_value_t * | obj,
|  | unsigned int | val
| ) |  |

Set device part of element identifier to given data of an element.

Parameters

  obj | Data of an element.
  val | Value for device part of element identifier.

void snd_ctl_elem_value_set_enumerated | ( | snd_ctl_elem_value_t * | obj,
|  | unsigned int | idx,
|  | unsigned int | val
| ) |  |

Set value of a specified member to given data as an element of enumerated type.

Parameters

  obj | Data of an element.
  idx | Index of member in the element.
  val | Value for the member.

void snd_ctl_elem_value_set_id | ( | snd_ctl_elem_value_t * | obj,
|  | const snd_ctl_elem_id_t * | ptr
| ) |  |

Set element identifier to given data of an element.

Parameters

  obj | Data of an element.
  ptr | Pointer to an element identifier.

void snd_ctl_elem_value_set_iec958 | ( | snd_ctl_elem_value_t * | obj,
|  | const snd_aes_iec958_t * | ptr
| ) |  |

Set value from given pointer to given data as an element of IEC958 type.

Parameters

  obj | Data of an element.
  ptr | Pointer to IEC958 data.

void snd_ctl_elem_value_set_index | ( | snd_ctl_elem_value_t * | obj,
|  | unsigned int | val
| ) |  |

Set index part of element identifier to given data of an element.

Parameters

  obj | Data of an element.
  val | Value for index part of element identifier.

void snd_ctl_elem_value_set_integer | ( | snd_ctl_elem_value_t * | obj,
|  | unsigned int | idx,
|  | long | val
| ) |  |

Set value of a specified member to given data as an element of integer type.

Parameters

  obj | Data of an element.
  idx | Index of member in the element.
  val | Value for the member.

void snd_ctl_elem_value_set_integer64 | ( | snd_ctl_elem_value_t * | obj,
|  | unsigned int | idx,
|  | long long | val
| ) |  |

Set value of a specified member to given data as an element of integer64 type.

Parameters

  obj | Data of an element.
  idx | Index of member in the element.
  val | Value for the member.

void snd_ctl_elem_value_set_interface | ( | snd_ctl_elem_value_t * | obj,
|  | snd_ctl_elem_iface_t | val
| ) |  |

Set interface part of element identifier to given data of an element.

Parameters

  obj | Data of an element.
  val | Value for interface part of element identifier.

void snd_ctl_elem_value_set_name | ( | snd_ctl_elem_value_t * | obj,
|  | const char * | val
| ) |  |

Set name part of element identifier to given data of an element.

Parameters

  obj | Data of an element.
  val | Value for name part of element identifier,

void snd_ctl_elem_value_set_numid | ( | snd_ctl_elem_value_t * | obj,
|  | unsigned int | val
| ) |  |

Set numeric identifier to given data of an element.

Parameters

  obj | Data of an element.
  val | Value for numeric identifier.

void snd_ctl_elem_value_set_subdevice | ( | snd_ctl_elem_value_t * | obj,
|  | unsigned int | val
| ) |  |

Set subdevice part of element identifier to given data of an element.

Parameters

  obj | Data of an element.
  val | Value for subdevice part of element identifier.

size_t snd_ctl_elem_value_sizeof | ( | void |  | ) |

Get size of data structure for an element.

Returns
  Size in bytes.

int snd_ctl_elem_write | ( | snd_ctl_t * | ctl,
|  | snd_ctl_elem_value_t * | data
| ) |  |

Set CTL element value.

Parameters

  ctl | CTL handle
  data | Data of an element.

Return values

  0 | on success
  >0 | on success when value was changed
  <0 | a negative error code

void snd_ctl_event_clear | ( | snd_ctl_event_t * | obj | ) |

clear given snd_ctl_event_t object

Parameters

  obj | pointer to object to clear

void snd_ctl_event_copy | ( | snd_ctl_event_t * | dst,
|  | const snd_ctl_event_t * | src
| ) |  |

copy one snd_ctl_event_t to another

Parameters

  dst | pointer to destination
  src | pointer to source

unsigned int snd_ctl_event_elem_get_device | ( | const snd_ctl_event_t * | obj | ) |

Get device part of CTL element identifier for an element related event.

Parameters

  obj | CTL event

Returns
  device part of element identifier

void snd_ctl_event_elem_get_id | ( | const snd_ctl_event_t * | obj,
|  | snd_ctl_elem_id_t * | ptr
| ) |  |

Get CTL element identifier for an element related event.

Parameters

  obj | CTL event
  ptr | Pointer to returned CTL element identifier

unsigned int snd_ctl_event_elem_get_index | ( | const snd_ctl_event_t * | obj | ) |

Get index part of CTL element identifier for an element related event.

Parameters

  obj | CTL event

Returns
  index part of element identifier

snd_ctl_elem_iface_t snd_ctl_event_elem_get_interface | ( | const snd_ctl_event_t * | obj | ) |

Get interface part of CTL element identifier for an element related event.

Parameters

  obj | CTL event

Returns
  interface part of element identifier

unsigned int snd_ctl_event_elem_get_mask | ( | const snd_ctl_event_t * | obj | ) |

Get event mask for an element related event.

Parameters

  obj | CTL event

Returns
  event mask for element related event

const char* snd_ctl_event_elem_get_name | ( | const snd_ctl_event_t * | obj | ) |

Get name part of CTL element identifier for an element related event.

Parameters

  obj | CTL event

Returns
  name part of element identifier

unsigned int snd_ctl_event_elem_get_numid | ( | const snd_ctl_event_t * | obj | ) |

Get element numeric identifier for an element related event.

Parameters

  obj | CTL event

Returns
  element numeric identifier

unsigned int snd_ctl_event_elem_get_subdevice | ( | const snd_ctl_event_t * | obj | ) |

Get subdevice part of CTL element identifier for an element related event.

Parameters

  obj | CTL event

Returns
  subdevice part of element identifier

void snd_ctl_event_free | ( | snd_ctl_event_t * | obj | ) |

frees a previously allocated snd_ctl_event_t

Parameters

  obj | pointer to object to free

snd_ctl_event_type_t snd_ctl_event_get_type | ( | const snd_ctl_event_t * | obj | ) |

Get type of a CTL event.

Parameters

  obj | CTL event

Returns
  CTL event type

int snd_ctl_event_malloc | ( | snd_ctl_event_t ** | ptr | ) |

allocate an invalid snd_ctl_event_t using standard malloc

Parameters

  ptr | returned pointer

Returns
  0 on success otherwise negative error code

size_t snd_ctl_event_sizeof | ( | void |  | ) |

get size of snd_ctl_event_t

Returns
  size in bytes

const char* snd_ctl_event_type_name | ( | snd_ctl_event_type_t | type | ) |

get name of a CTL event type

Parameters

  type | CTL event type

Returns
  ascii name of CTL event type

int snd_ctl_get_dB_range | ( | snd_ctl_t * | ctl,
|  | const snd_ctl_elem_id_t * | id,
|  | long * | min,
|  | long * | max
| ) |  |

Get the dB min/max values on the given control element.

Parameters

  ctl | the control handler
  id | the element id
  min | the pointer to store the minimum dB value (in 0.01dB unit)
  max | the pointer to store the maximum dB value (in 0.01dB unit)

Returns
  0 if successful, or a negative error code

int snd_ctl_get_power_state | ( | snd_ctl_t * | ctl,
|  | unsigned int * | state
| ) |  |

Get actual Power State.

Parameters

  ctl | CTL handle
  state | Destination value

Returns
  0 on success otherwise a negative error code

const char* snd_ctl_name | ( | snd_ctl_t * | ctl | ) |

get identifier of CTL handle

Parameters

  ctl | CTL handle

Returns
  ascii identifier of CTL handle

Returns the ASCII identifier of given CTL handle. It's the same identifier specified in snd_ctl_open().

int snd_ctl_nonblock | ( | snd_ctl_t * | ctl,
|  | int | nonblock
| ) |  |

set nonblock mode

Parameters

  ctl | CTL handle
  nonblock | 0 = block, 1 = nonblock mode, 2 = abort

Returns
  0 on success otherwise a negative error code

int snd_ctl_open | ( | snd_ctl_t ** | ctlp,
|  | const char * | name,
|  | int | mode
| ) |  |

Opens a CTL.

Parameters

  ctlp | Returned CTL handle
  name | ASCII identifier of the CTL handle
  mode | Open mode (see SND_CTL_NONBLOCK, SND_CTL_ASYNC)

Returns
  0 on success otherwise a negative error code

int snd_ctl_open_fallback | ( | snd_ctl_t ** | ctlp,
|  | snd_config_t * | root,
|  | const char * | name,
|  | const char * | orig_name,
|  | int | mode
| ) |  |

Opens a fallback CTL.

Parameters

  ctlp | Returned CTL handle
  root | Configuration root
  name | ASCII identifier of the CTL handle used as fallback
  orig_name | The original ASCII name
  mode | Open mode (see SND_CTL_NONBLOCK, SND_CTL_ASYNC)

Returns
  0 on success otherwise a negative error code

int snd_ctl_open_lconf | ( | snd_ctl_t ** | ctlp,
|  | const char * | name,
|  | int | mode,
|  | snd_config_t * | lconf
| ) |  |

Opens a CTL using local configuration.

Parameters

  ctlp | Returned CTL handle
  name | ASCII identifier of the CTL handle
  mode | Open mode (see SND_CTL_NONBLOCK, SND_CTL_ASYNC)
  lconf | Local configuration

Returns
  0 on success otherwise a negative error code

int snd_ctl_poll_descriptors | ( | snd_ctl_t * | ctl,
|  | struct pollfd * | pfds,
|  | unsigned int | space
| ) |  |

get poll descriptors

Parameters

  ctl | CTL handle
  pfds | array of poll descriptors
  space | space in the poll descriptor array

Returns
  count of filled descriptors

int snd_ctl_poll_descriptors_count | ( | snd_ctl_t * | ctl | ) |

get count of poll descriptors for CTL handle

Parameters

  ctl | CTL handle

Returns
  count of poll descriptors

int snd_ctl_poll_descriptors_revents | ( | snd_ctl_t * | ctl,
|  | struct pollfd * | pfds,
|  | unsigned int | nfds,
|  | unsigned short * | revents
| ) |  |

get returned events from poll descriptors

Parameters

  ctl | CTL handle
  pfds | array of poll descriptors
  nfds | count of poll descriptors
  revents | returned events

Returns
  zero if success, otherwise a negative error code

int snd_ctl_read | ( | snd_ctl_t * | ctl,
|  | snd_ctl_event_t * | event
| ) |  |

Read an event.

Parameters

  ctl | CTL handle
  event | Event pointer

Returns
  number of events read otherwise a negative error code on failure

int snd_ctl_set_power_state | ( | snd_ctl_t * | ctl,
|  | unsigned int | state
| ) |  |

Set Power State to given SND_CTL_POWER_* value and do the power management.

Parameters

  ctl | CTL handle
  state | Desired Power State

Returns
  0 on success otherwise a negative error code

int snd_ctl_subscribe_events | ( | snd_ctl_t * | ctl,
|  | int | subscribe
| ) |  |

Ask to be informed about events (poll, snd_async_add_ctl_handler, snd_ctl_read)

Parameters

  ctl | CTL handle
  subscribe | 0 = unsubscribe, 1 = subscribe, -1 = check subscribe or not

Returns
  0 on success otherwise a negative error code

snd_ctl_type_t snd_ctl_type | ( | snd_ctl_t * | ctl | ) |

get type of CTL handle

Parameters

  ctl | CTL handle

Returns
  type of CTL handle

Returns the type snd_ctl_type_t of given CTL handle.

int snd_ctl_wait | ( | snd_ctl_t * | ctl,
|  | int | timeout
| ) |  |

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

Parameters

  ctl | CTL handle
  timeout | maximum time in milliseconds to wait

Returns
  0 otherwise a negative error code on failure

int snd_device_name_free_hint | ( | void ** | hints | ) |

Free a list of device name hints.

Parameters

  hints | List to free

Returns
  zero if success, otherwise a negative error code

char* snd_device_name_get_hint | ( | const void * | hint,
|  | const char * | id
| ) |  |

Extract a value from a hint.

Parameters

  hint | A pointer to hint
  id | Hint value to extract ("NAME", "DESC", or "IOID", see below)

Returns
  an allocated ASCII string if success, otherwise NULL

List of valid IDs: NAME - name of device DESC - description of device IOID - input / output identification ("Input" or "Output"), NULL means both

The return value should be freed when no longer needed.

int snd_device_name_hint | ( | int | card,
|  | const char * | iface,
|  | void *** | hints
| ) |  |

Get a set of device name hints.

Parameters

  card | Card number or -1 (means all cards)
  iface | Interface identification (like "pcm", "rawmidi", "timer", "seq")
  hints | Result - array of device name hints

Returns
  zero if success, otherwise a negative error code

hints will receive a NULL-terminated array of device name hints, which can be passed to snd_device_name_get_hint to extract usable values. When no longer needed, hints should be passed to snd_device_name_free_hint to release resources.

User-defined hints are gathered from namehint.IFACE tree like:

`namehint.pcm {
myfile "file:FILE=/tmp/soundwave.raw|Save sound output to /tmp/soundwave.raw"
myplug "plug:front:Do all conversions for front speakers"
}`

Note: The device description is separated with '|' char.

Special variables: defaults.namehint.showall specifies if all device definitions are accepted (boolean type).

int snd_tlv_convert_from_dB | ( | unsigned int * | tlv,
|  | long | rangemin,
|  | long | rangemax,
|  | long | db_gain,
|  | long * | value,
|  | int | xdir
| ) |  |

Convert from dB gain to the corresponding raw value.

Parameters

  tlv | the TLV source returned by snd_tlv_parse_dB_info()
  rangemin | the minimum value of the raw volume
  rangemax | the maximum value of the raw volume
  db_gain | the dB gain to convert (in 0.01dB unit)
  value | the pointer to store the converted raw volume value
  xdir | the direction for round-up. The value is round up when this is positive.

Returns
  0 if successful, or a negative error code

int snd_tlv_convert_to_dB | ( | unsigned int * | tlv,
|  | long | rangemin,
|  | long | rangemax,
|  | long | volume,
|  | long * | db_gain
| ) |  |

Convert the given raw volume value to a dB gain.

Parameters

  tlv | the TLV source returned by snd_tlv_parse_dB_info()
  rangemin | the minimum value of the raw volume
  rangemax | the maximum value of the raw volume
  volume | the raw volume value to convert
  db_gain | the dB gain (in 0.01dB unit)

Returns
  0 if successful, or a negative error code

int snd_tlv_get_dB_range | ( | unsigned int * | tlv,
|  | long | rangemin,
|  | long | rangemax,
|  | long * | min,
|  | long * | max
| ) |  |

Get the dB min/max values.

Parameters

  tlv | the TLV source returned by snd_tlv_parse_dB_info()
  rangemin | the minimum value of the raw volume
  rangemax | the maximum value of the raw volume
  min | the pointer to store the minimum dB value (in 0.01dB unit)
  max | the pointer to store the maximum dB value (in 0.01dB unit)

Returns
  0 if successful, or a negative error code

int snd_tlv_parse_dB_info | ( | unsigned int * | tlv,
|  | unsigned int | tlv_size,
|  | unsigned int ** | db_tlvp
| ) |  |

Parse TLV stream and retrieve dB information.

Parameters

  tlv | the TLV source
  tlv_size | the byte size of TLV source
  db_tlvp | the pointer stored the dB TLV information

Returns
  the byte size of dB TLV information if found in the given TLV source, or a negative error code.

This function parses the given TLV source and stores the TLV start point if the TLV information regarding dB conversion is found. The stored TLV pointer can be passed to the convesion functions snd_tlv_convert_to_dB(), snd_tlv_convert_from_dB() and snd_tlv_get_dB_range().