ALSA project - the C library reference
 All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
Modules | Data Structures | Macros | Typedefs | Enumerations | Functions
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
#define snd_ctl_card_info_alloca(ptr)
 allocate an invalid snd_ctl_card_info_t using standard alloca
#define snd_ctl_event_alloca(ptr)
 allocate an invalid snd_ctl_event_t using standard alloca
#define snd_ctl_elem_list_alloca(ptr)
 allocate an invalid snd_ctl_elem_list_t using standard alloca
#define snd_ctl_elem_info_alloca(ptr)
 allocate an invalid snd_ctl_elem_info_t using standard alloca
#define snd_ctl_elem_value_alloca(ptr)
 allocate an invalid snd_ctl_elem_value_t using standard alloca

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.
int snd_card_next (int *card)
 Try to determine the next card.
int snd_card_get_index (const char *name)
 Convert card string to an integer value.
int snd_card_get_name (int card, char **name)
 Obtain the card name.
int snd_card_get_longname (int card, char **name)
 Obtain the card long name.
int snd_device_name_hint (int card, const char *iface, void ***hints)
 Get a set of device name hints.
int snd_device_name_free_hint (void **hints)
 Free a list of device name hints.
char * snd_device_name_get_hint (const void *hint, const char *id)
 Extract a value from a hint.
int snd_ctl_open (snd_ctl_t **ctl, const char *name, int mode)
 Opens a CTL.
int snd_ctl_open_lconf (snd_ctl_t **ctl, const char *name, int mode, snd_config_t *lconf)
 Opens a CTL using local configuration.
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.
int snd_ctl_close (snd_ctl_t *ctl)
 close CTL handle
int snd_ctl_nonblock (snd_ctl_t *ctl, int nonblock)
 set nonblock mode
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.
snd_ctl_tsnd_async_handler_get_ctl (snd_async_handler_t *handler)
 Return CTL handle related to an async handler.
int snd_ctl_poll_descriptors_count (snd_ctl_t *ctl)
 get count of poll descriptors for CTL handle
int snd_ctl_poll_descriptors (snd_ctl_t *ctl, struct pollfd *pfds, unsigned int space)
 get 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
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)
int snd_ctl_card_info (snd_ctl_t *ctl, snd_ctl_card_info_t *info)
 Get card related information.
int snd_ctl_elem_list (snd_ctl_t *ctl, snd_ctl_elem_list_t *list)
 Get a list of element identifiers.
int snd_ctl_elem_info (snd_ctl_t *ctl, snd_ctl_elem_info_t *info)
 Get CTL element information.
int snd_ctl_elem_read (snd_ctl_t *ctl, snd_ctl_elem_value_t *data)
 Get CTL element value.
int snd_ctl_elem_write (snd_ctl_t *ctl, snd_ctl_elem_value_t *data)
 Set CTL element value.
int snd_ctl_elem_lock (snd_ctl_t *ctl, snd_ctl_elem_id_t *id)
 Lock CTL element.
int snd_ctl_elem_unlock (snd_ctl_t *ctl, snd_ctl_elem_id_t *id)
 Unlock CTL element.
int snd_ctl_elem_tlv_read (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, unsigned int *tlv, unsigned int tlv_size)
 Set given data to an element as threshold level.
int snd_ctl_elem_tlv_write (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, const unsigned int *tlv)
 Set given data to an element as threshold level.
int snd_ctl_elem_tlv_command (snd_ctl_t *ctl, const snd_ctl_elem_id_t *id, const unsigned int *tlv)
 Set given data to an element as threshold level.
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.
int snd_ctl_get_power_state (snd_ctl_t *ctl, unsigned int *state)
 Get actual Power State.
int snd_ctl_read (snd_ctl_t *ctl, snd_ctl_event_t *event)
 Read an event.
int snd_ctl_wait (snd_ctl_t *ctl, int timeout)
 Wait for a CTL to become ready (i.e. at least one event pending)
const char * snd_ctl_name (snd_ctl_t *ctl)
 get identifier of CTL handle
snd_ctl_type_t snd_ctl_type (snd_ctl_t *ctl)
 get type of CTL handle
const char * snd_ctl_elem_type_name (snd_ctl_elem_type_t type)
 get name of a CTL element type
const char * snd_ctl_elem_iface_name (snd_ctl_elem_iface_t iface)
 get name of a CTL element related interface
const char * snd_ctl_event_type_name (snd_ctl_event_type_t type)
 get name of a CTL event type
unsigned int snd_ctl_event_elem_get_mask (const snd_ctl_event_t *obj)
 Get event mask for an element related event.
unsigned int snd_ctl_event_elem_get_numid (const snd_ctl_event_t *obj)
 Get element numeric identifier for an element related event.
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.
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.
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.
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.
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.
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.
int snd_ctl_elem_list_alloc_space (snd_ctl_elem_list_t *obj, unsigned int entries)
 allocate space for CTL element identifiers list
void snd_ctl_elem_list_free_space (snd_ctl_elem_list_t *obj)
 free previously allocated space for CTL element identifiers list
char * snd_ctl_ascii_elem_id_get (snd_ctl_elem_id_t *id)
 return ASCII CTL element identifier name
int snd_ctl_ascii_elem_id_parse (snd_ctl_elem_id_t *dst, const char *str)
 parse ASCII string as CTL element identifier
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
size_t snd_ctl_elem_id_sizeof (void)
 get size of snd_ctl_elem_id_t
int snd_ctl_elem_id_malloc (snd_ctl_elem_id_t **ptr)
 allocate an invalid snd_ctl_elem_id_t using standard malloc
void snd_ctl_elem_id_free (snd_ctl_elem_id_t *obj)
 frees a previously allocated snd_ctl_elem_id_t
void snd_ctl_elem_id_clear (snd_ctl_elem_id_t *obj)
 clear given snd_ctl_elem_id_t object
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
unsigned int snd_ctl_elem_id_get_numid (const snd_ctl_elem_id_t *obj)
 Get numeric identifier from a CTL element identifier.
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.
unsigned int snd_ctl_elem_id_get_device (const snd_ctl_elem_id_t *obj)
 Get device part of a CTL element identifier.
unsigned int snd_ctl_elem_id_get_subdevice (const snd_ctl_elem_id_t *obj)
 Get subdevice part of a CTL element identifier.
const char * snd_ctl_elem_id_get_name (const snd_ctl_elem_id_t *obj)
 Get name part of a CTL element identifier.
unsigned int snd_ctl_elem_id_get_index (const snd_ctl_elem_id_t *obj)
 Get index part of a CTL element identifier.
void snd_ctl_elem_id_set_numid (snd_ctl_elem_id_t *obj, unsigned int val)
 Set numeric identifier for a CTL element identifier.
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.
void snd_ctl_elem_id_set_device (snd_ctl_elem_id_t *obj, unsigned int val)
 Set device part for a CTL element 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.
void snd_ctl_elem_id_set_name (snd_ctl_elem_id_t *obj, const char *val)
 Set name part for a CTL element identifier.
void snd_ctl_elem_id_set_index (snd_ctl_elem_id_t *obj, unsigned int val)
 Set index part for a CTL element identifier.
size_t snd_ctl_card_info_sizeof (void)
 get size of snd_ctl_card_info_t
int snd_ctl_card_info_malloc (snd_ctl_card_info_t **ptr)
 allocate an invalid snd_ctl_card_info_t using standard malloc
void snd_ctl_card_info_free (snd_ctl_card_info_t *obj)
 frees a previously allocated snd_ctl_card_info_t
void snd_ctl_card_info_clear (snd_ctl_card_info_t *obj)
 clear given snd_ctl_card_info_t object
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
int snd_ctl_card_info_get_card (const snd_ctl_card_info_t *obj)
 Get card number from a CTL card info.
const char * snd_ctl_card_info_get_id (const snd_ctl_card_info_t *obj)
 Get card identifier from a CTL card info.
const char * snd_ctl_card_info_get_driver (const snd_ctl_card_info_t *obj)
 Get card driver name from a CTL card info.
const char * snd_ctl_card_info_get_name (const snd_ctl_card_info_t *obj)
 Get card name from a CTL card info.
const char * snd_ctl_card_info_get_longname (const snd_ctl_card_info_t *obj)
 Get card long name from a CTL card info.
const char * snd_ctl_card_info_get_mixername (const snd_ctl_card_info_t *obj)
 Get card mixer name from a CTL card info.
const char * snd_ctl_card_info_get_components (const snd_ctl_card_info_t *obj)
 Get card component list from a CTL card info.
size_t snd_ctl_event_sizeof (void)
 get size of snd_ctl_event_t
int snd_ctl_event_malloc (snd_ctl_event_t **ptr)
 allocate an invalid snd_ctl_event_t using standard malloc
void snd_ctl_event_free (snd_ctl_event_t *obj)
 frees a previously allocated snd_ctl_event_t
void snd_ctl_event_clear (snd_ctl_event_t *obj)
 clear given snd_ctl_event_t object
void snd_ctl_event_copy (snd_ctl_event_t *dst, const snd_ctl_event_t *src)
 copy one snd_ctl_event_t to another
snd_ctl_event_type_t snd_ctl_event_get_type (const snd_ctl_event_t *obj)
 Get type of a CTL event.
size_t snd_ctl_elem_list_sizeof (void)
 get size of snd_ctl_elem_list_t
int snd_ctl_elem_list_malloc (snd_ctl_elem_list_t **ptr)
 allocate an invalid snd_ctl_elem_list_t using standard malloc
void snd_ctl_elem_list_free (snd_ctl_elem_list_t *obj)
 frees a previously allocated snd_ctl_elem_list_t
void snd_ctl_elem_list_clear (snd_ctl_elem_list_t *obj)
 clear given snd_ctl_elem_list_t object
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
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.
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.
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)
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.
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.
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.
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.
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.
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.
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.
size_t snd_ctl_elem_info_sizeof (void)
 get size of snd_ctl_elem_info_t
int snd_ctl_elem_info_malloc (snd_ctl_elem_info_t **ptr)
 allocate an invalid snd_ctl_elem_info_t using standard malloc
void snd_ctl_elem_info_free (snd_ctl_elem_info_t *obj)
 frees a previously allocated snd_ctl_elem_info_t
void snd_ctl_elem_info_clear (snd_ctl_elem_info_t *obj)
 clear given snd_ctl_elem_info_t object
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
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.
int snd_ctl_elem_info_is_readable (const snd_ctl_elem_info_t *obj)
 Get info about readability from a CTL element id/info.
int snd_ctl_elem_info_is_writable (const snd_ctl_elem_info_t *obj)
 Get info about writability from a CTL element id/info.
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.
int snd_ctl_elem_info_is_inactive (const snd_ctl_elem_info_t *obj)
 Get info about status from a CTL element id/info.
int snd_ctl_elem_info_is_locked (const snd_ctl_elem_info_t *obj)
 Get info whether an element is locked.
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.
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.
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.
int snd_ctl_elem_info_is_owner (const snd_ctl_elem_info_t *obj)
 Get info if I own an element.
int snd_ctl_elem_info_is_user (const snd_ctl_elem_info_t *obj)
 Get info if it's a user element.
pid_t snd_ctl_elem_info_get_owner (const snd_ctl_elem_info_t *obj)
 Get owner of a locked element.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
int snd_ctl_elem_info_get_dimensions (const snd_ctl_elem_info_t *obj)
 Get count of dimensions for given element.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
int snd_ctl_elem_remove (snd_ctl_t *ctl, snd_ctl_elem_id_t *id)
 Remove an user CTL element.
size_t snd_ctl_elem_value_sizeof (void)
 Get size of data structure for an element.
int snd_ctl_elem_value_malloc (snd_ctl_elem_value_t **ptr)
 Allocate an invalid snd_ctl_elem_value_t using standard malloc(3).
void snd_ctl_elem_value_free (snd_ctl_elem_value_t *obj)
 Frees a previously allocated data of an element.
void snd_ctl_elem_value_clear (snd_ctl_elem_value_t *obj)
 Clear given data of an element.
void snd_ctl_elem_value_copy (snd_ctl_elem_value_t *dst, const snd_ctl_elem_value_t *src)
 Copy two data of elements.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
int snd_tlv_parse_dB_info (unsigned int *tlv, unsigned int tlv_size, unsigned int **db_tlvp)
 Parse TLV stream and retrieve dB information.
int snd_tlv_get_dB_range (unsigned int *tlv, long rangemin, long rangemax, long *min, long *max)
 Get the dB min/max values.
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.
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.
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.
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.
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.

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:
ptrreturned pointer
#define snd_ctl_elem_id_alloca (   ptr)

allocate an invalid snd_ctl_elem_id_t using standard alloca

Parameters:
ptrreturned pointer
#define snd_ctl_elem_info_alloca (   ptr)

allocate an invalid snd_ctl_elem_info_t using standard alloca

Parameters:
ptrreturned pointer
#define snd_ctl_elem_list_alloca (   ptr)

allocate an invalid snd_ctl_elem_list_t using standard alloca

Parameters:
ptrreturned pointer
#define snd_ctl_elem_value_alloca (   ptr)

allocate an invalid snd_ctl_elem_value_t using standard alloca

Parameters:
ptrreturned pointer
#define snd_ctl_event_alloca (   ptr)

allocate an invalid snd_ctl_event_t using standard alloca

Parameters:
ptrreturned 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

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

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

Event class

Enumerator:
SND_CTL_EVENT_ELEM 

Elements related event

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:
handlerReturned handler handle
ctlCTL handle
callbackCallback function
private_dataCallback 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:
handlerAsync handler handle
Returns:
CTL handle
int snd_card_get_index ( const char *  string)

Convert card string to an integer value.

Parameters:
stringString 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:
cardCard number
nameResult - 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:
cardCard number
nameResult - 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:
cardCard 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:
rcardpointer 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:
ctlA handle of backend module for control interface.
infoCommon iformation for a new element set, with ID of the first new element.
element_countThe number of elements added by this operation.
member_countThe 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:
ctlA handle of backend module for control interface.
infoCommon iformation for a new element set, with ID of the first new element.
element_countThe number of elements added by this operation.
member_countThe 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:
ctlA handle of backend module for control interface.
infoCommon iformation for a new element set, with ID of the first new element.
element_countThe number of elements added by this operation.
member_countThe number of members which a element has to represent its states.
itemsRange of possible values (0 ... items - 1).
labelsAn 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:
ctlA handle of backend module for control interface.
infoCommon iformation for a new element set, with ID of the first new element.
element_countThe number of elements added by this operation.
member_countThe number of members which a element has to represent its states.
minMinimum value for each member of the elements.
maxMaximum value for each member of the elements.
stepThe 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:
ctlA handle of backend module for control interface.
infoCommon iformation for a new element set, with ID of the first new element.
element_countThe number of elements added by this operation.
member_countThe number of members which a element has to represent its states.
minMinimum value for each member of the elements.
maxMaximum value for each member of the elements.
stepThe 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:
idCTL 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:
dstdestination CTL identifier
strsource 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:
handleCTL handle
dstdestination CTL element value
infoCTL element info structure
valuesource 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:
ctlCTL handle
infoCard 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:
objpointer 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:
dstpointer to destination
srcpointer to source
void snd_ctl_card_info_free ( snd_ctl_card_info_t obj)

frees a previously allocated snd_ctl_card_info_t

Parameters:
objpointer 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
ptrreturned 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:
ctlCTL 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:
ctlthe control handler
idthe element id
db_gainthe dB gain to convert (in 0.01dB unit)
valuethe pointer to store the converted raw volume value
xdirthe 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:
ctlthe control handler
idthe element id
volumethe raw volume value to convert
db_gainthe 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]ctlA handle of backend module for control interface.
[in,out]idID 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:
objpointer 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:
dstpointer to destination
srcpointer to source
void snd_ctl_elem_id_free ( snd_ctl_elem_id_t obj)

frees a previously allocated snd_ctl_elem_id_t

Parameters:
objpointer 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
ptrreturned 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:
objCTL element identifier
valCTL 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:
objCTL element identifier
valCTL 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:
objCTL element identifier
valCTL 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:
objCTL element identifier
valCTL 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:
objCTL element identifier
valCTL 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:
objCTL element identifier
valCTL 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:
ifaceCTL 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:
ctlCTL handle
infoCTL 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:
objpointer 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:
dstpointer to destination
srcpointer to source
void snd_ctl_elem_info_free ( snd_ctl_elem_info_t obj)

frees a previously allocated snd_ctl_elem_info_t

Parameters:
objpointer 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:
objCTL 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:
objCTL 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:
objCTL element id/info
idxThe dimension index
Returns:
zero value if no dimension width is defined, otherwise positive value with with of specified dimension
int snd_ctl_elem_info_get_dimensions ( const snd_ctl_elem_info_t obj)

Get count of dimensions for given element.

Parameters:
objCTL element id/info
Returns:
zero value if no dimensions are defined, otherwise positive value with count of dimensions
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:
objCTL element id/info
ptrPointer 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
ptrreturned 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:
objCTL element id/info
valdevice 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:
infoInformation of an element.
dimensionDimension 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.
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:
objCTL element id/info
ptrCTL 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:
objCTL element id/info
valindex 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:
objCTL element id/info
valinterface 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:
objCTL element id/info
valitem 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:
objCTL element id/info
valname 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:
objCTL element id/info
valelement 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:
objCTL element id/info
valsubdevice 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:
ctlCTL handle
listCTL 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:
objCTL element identifiers list
entriesEntries 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:
objpointer 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:
dstpointer to destination
srcpointer to source
void snd_ctl_elem_list_free ( snd_ctl_elem_list_t obj)

frees a previously allocated snd_ctl_elem_list_t

Parameters:
objpointer 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:
objCTL 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:
objCTL 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:
objCTL element identifier list
idxIndex 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:
objCTL element identifier list
idxIndex of entry
ptrPointer 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:
objCTL element identifier list
idxIndex 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:
objCTL element identifier list
idxIndex 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:
objCTL element identifier list
idxIndex 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:
objCTL element identifier list
idxIndex 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:
objCTL element identifier list
idxIndex 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:
objCTL 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:
ptrreturned 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:
objCTL element identifiers list
valindex 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:
ctlCTL handle
idCTL 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:
ctlCTL handle
dataData 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:
ctlCTL handle
idCTL 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:
objData of an element.
dataPointer for byte array.
sizeThe 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 
)

Set given data to an element as threshold level.

Parameters:
ctlA handle of backend module for control interface.
idID of an element.
tlvAn array with members of unsigned int type. The second member must represent total bytes of the rest of array.
Return values:
0on success
>0on success when value was changed
<0a negative error code
int snd_ctl_elem_tlv_read ( snd_ctl_t ctl,
const snd_ctl_elem_id_t id,
unsigned int *  tlv,
unsigned int  tlv_size 
)

Set given data to an element as threshold level.

Parameters:
ctlA handle of backend module for control interface.
idID of an element.
tlvAn array with members of unsigned int type.
tlv_sizeThe length of the array.
Returns:
0 on success otherwise a negative error code
int snd_ctl_elem_tlv_write ( snd_ctl_t ctl,
const snd_ctl_elem_id_t id,
const unsigned int *  tlv 
)

Set given data to an element as threshold level.

Parameters:
ctlA handle of backend module for control interface.
idID of an element.
tlvAn array with members of unsigned int type. The second member must represent total bytes of the rest of array.
Return values:
0on success
>0on success when value was changed
<0a negative error code
const char* snd_ctl_elem_type_name ( snd_ctl_elem_type_t  type)

get name of a CTL element type

Parameters:
typeCTL 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:
ctlCTL handle
idCTL 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:
objData 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:
leftPointer to first data.
rightPointer 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:
dstPointer to destination.
srcPointer to source.
void snd_ctl_elem_value_free ( snd_ctl_elem_value_t obj)

Frees a previously allocated data of an element.

Parameters:
objData 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:
objData of an element.
idxIndex 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:
objData of an element.
idxIndex 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:
objData 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:
objData 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:
objData of an element.
idxIndex 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:
objData of an element.
ptrPointer 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:
objData of an element.
ptrPointer 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:
objData 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:
objData of an element.
idxIndex 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:
objData of an element.
idxIndex 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:
objData 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:
objData 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:
objData 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:
objData 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:
ptrReturned 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:
objData of an element.
idxIndex of member in the element.
valValue 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:
objData of an element.
idxIndex of member in the element.
valValue 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:
objData of an element.
valValue 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:
objData of an element.
idxIndex of member in the element.
valValue 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:
objData of an element.
ptrPointer 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:
objData of an element.
ptrPointer 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:
objData of an element.
valValue 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:
objData of an element.
idxIndex of member in the element.
valValue 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:
objData of an element.
idxIndex of member in the element.
valValue 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:
objData of an element.
valValue 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:
objData of an element.
valValue 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:
objData of an element.
valValue 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:
objData of an element.
valValue 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:
ctlCTL handle
dataData of an element.
Return values:
0on success
>0on success when value was changed
<0a negative error code
void snd_ctl_event_clear ( snd_ctl_event_t obj)

clear given snd_ctl_event_t object

Parameters:
objpointer 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:
dstpointer to destination
srcpointer 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:
objCTL 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:
objCTL event
ptrPointer 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objCTL 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:
objpointer 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:
objCTL 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:
ptrreturned 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:
typeCTL 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:
ctlthe control handler
idthe element id
minthe pointer to store the minimum dB value (in 0.01dB unit)
maxthe 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:
ctlCTL handle
stateDestination 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:
ctlCTL 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:
ctlCTL handle
nonblock0 = 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:
ctlpReturned CTL handle
nameASCII identifier of the CTL handle
modeOpen 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:
ctlpReturned CTL handle
rootConfiguration root
nameASCII identifier of the CTL handle used as fallback
orig_nameThe original ASCII name
modeOpen 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:
ctlpReturned CTL handle
nameASCII identifier of the CTL handle
modeOpen mode (see SND_CTL_NONBLOCK, SND_CTL_ASYNC)
lconfLocal 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:
ctlCTL handle
pfdsarray of poll descriptors
spacespace 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:
ctlCTL 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:
ctlCTL handle
pfdsarray of poll descriptors
nfdscount of poll descriptors
reventsreturned 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:
ctlCTL handle
eventEvent 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:
ctlCTL handle
stateDesired 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:
ctlCTL handle
subscribe0 = 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:
ctlCTL 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:
ctlCTL handle
timeoutmaximum 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:
hintsList 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:
hintA pointer to hint
idHint 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:
cardCard number or -1 (means all cards)
ifaceInterface identification (like "pcm", "rawmidi", "timer", "seq")
hintsResult - 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:
tlvthe TLV source returned by snd_tlv_parse_dB_info()
rangeminthe minimum value of the raw volume
rangemaxthe maximum value of the raw volume
db_gainthe dB gain to convert (in 0.01dB unit)
valuethe pointer to store the converted raw volume value
xdirthe 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:
tlvthe TLV source returned by snd_tlv_parse_dB_info()
rangeminthe minimum value of the raw volume
rangemaxthe maximum value of the raw volume
volumethe raw volume value to convert
db_gainthe 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:
tlvthe TLV source returned by snd_tlv_parse_dB_info()
rangeminthe minimum value of the raw volume
rangemaxthe maximum value of the raw volume
minthe pointer to store the minimum dB value (in 0.01dB unit)
maxthe 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:
tlvthe TLV source
tlv_sizethe byte size of TLV source
db_tlvpthe 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().