# External Control Plugin SDK

## Data Structures

struct | snd_ctl_ext_t
struct | snd_ctl_ext_callback_t

## Files

file | control_ext.c

| External Control Plugin SDK.

## Defines

#define | SND_CTL_PLUGIN_ENTRY(name) _snd_ctl_##name##_open
#define | SND_CTL_PLUGIN_SYMBOL(name) SND_DLSYM_BUILD_VERSION(SND_CTL_PLUGIN_ENTRY(name), SND_CONTROL_DLSYM_VERSION);
#define | SND_CTL_PLUGIN_DEFINE_FUNC(plugin)
#define | SND_CTL_EXT_VERSION_MAJOR 1
#define | SND_CTL_EXT_VERSION_MINOR 0
#define | SND_CTL_EXT_VERSION_TINY 1
#define | SND_CTL_EXT_VERSION
#define | SND_CTL_EXT_KEY_NOT_FOUND (snd_ctl_ext_key_t)(-1)

## Typedefs

typedef unsigned long | snd_ctl_ext_key_t
typedef snd_ctl_ext | snd_ctl_ext_t
typedef snd_ctl_ext_callback | snd_ctl_ext_callback_t
typedef int( | snd_ctl_ext_tlv_rw_t )(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, int op_flag, unsigned int numid, unsigned int *tlv, unsigned int tlv_size)

## Enumerations

enum

snd_ctl_ext_access_t {
SND_CTL_EXT_ACCESS_READ = (1<<0), SND_CTL_EXT_ACCESS_WRITE = (1<<1), SND_CTL_EXT_ACCESS_READWRITE = (3<<0), SND_CTL_EXT_ACCESS_VOLATILE = (1<<2),
SND_CTL_EXT_ACCESS_TLV_READ = (1<<4), SND_CTL_EXT_ACCESS_TLV_WRITE = (1<<5), SND_CTL_EXT_ACCESS_TLV_READWRITE = (3<<4), SND_CTL_EXT_ACCESS_TLV_COMMAND = (1<<6),
SND_CTL_EXT_ACCESS_INACTIVE = (1<<8), SND_CTL_EXT_ACCESS_TLV_CALLBACK = (1<<28)
}

## Functions

int | snd_ctl_ext_create (snd_ctl_ext_t *ext, const char *name, int mode)
| Create an external control plugin instance.
int | snd_ctl_ext_delete (snd_ctl_ext_t *ext)
| Delete the external control plugin.

## Define Documentation

#define SND_CTL_EXT_KEY_NOT_FOUND (snd_ctl_ext_key_t)(-1)

find_elem callback returns this if no matching control element is found

#define SND_CTL_EXT_VERSION

Value:

    ((SND_CTL_EXT_VERSION_MAJOR<<16) |\
                                             (SND_CTL_EXT_VERSION_MINOR<<8) |\
                                             (SND_CTL_EXT_VERSION_TINY))

external plugin protocol version

#define SND_CTL_EXT_VERSION_MAJOR 1

Protocol major version

#define SND_CTL_EXT_VERSION_MINOR 0

Protocol minor version

#define SND_CTL_EXT_VERSION_TINY 1

Protocol tiny version

#define SND_CTL_PLUGIN_DEFINE_FUNC | ( | plugin |  | ) |

Value:

    int SND_CTL_PLUGIN_ENTRY(plugin) (snd_ctl_t **handlep, const char *name,\
                                      snd_config_t *root, snd_config_t *conf, int mode)

Define the control plugin

#define SND_CTL_PLUGIN_ENTRY | ( | name |  | ) | _snd_ctl_##name##_open

Define the object entry for external control plugins

#define SND_CTL_PLUGIN_SYMBOL | ( | name |  | ) | SND_DLSYM_BUILD_VERSION(SND_CTL_PLUGIN_ENTRY(name), SND_CONTROL_DLSYM_VERSION);

Define the symbols of the given control plugin with versions

## Typedef Documentation

typedef struct snd_ctl_ext_callback snd_ctl_ext_callback_t`[read]`

Callback table of control ext

typedef unsigned long snd_ctl_ext_key_t

Key to access a control pointer

typedef struct snd_ctl_ext snd_ctl_ext_t`[read]`

External control plugin handle

typedef int( snd_ctl_ext_tlv_rw_t)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, int op_flag, unsigned int numid, unsigned int *tlv, unsigned int tlv_size)

Callback to handle TLV commands.

## Enumeration Type Documentation

enum snd_ctl_ext_access_t

The access type bits stored in get_attribute callback

## Function Documentation

int snd_ctl_ext_create | ( | snd_ctl_ext_t * | ext,
|  | const char * | name,
|  | int | mode |
| ) |  |  |

Create an external control plugin instance.

Parameters:

  | ext | the plugin handle
  | name | name of control
  | mode | control open mode

Returns:
  0 if successful, or a negative error code

Creates the external control instance.

int snd_ctl_ext_delete | ( | snd_ctl_ext_t * | ext | ) |

Delete the external control plugin.

Parameters:

  | ext | the plugin handle

Returns:
  0 if successful, or a negative error code

All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Defines