snd_switch_t

Information about a mixer's switch

Synopsis:

typedef struct snd_switch
{
    int32_t iface;
    int32_t device;
    int32_t channel;
    uint8_t name[36];
    uint32_t type;
    uint32_t subtype;
    union
    {
        uint32_t enable:1;

        struct
        {
            uint8_t data;
            uint8_t low;
            uint8_t high;
        }
        byte;

        struct
        {
            uint16_t data;
            uint16_t low;
            uint16_t high;
        }
        word;

        struct
        {
            uint32_t data;
            uint32_t low;
            uint32_t high;
        }
        dword;

        struct
        {
            uint32_t data;
            uint32_t items[30];
            uint32_t items_cnt;
        }
        list;

        struct
        {
            uint8_t selection;
            char    strings[11][11];
            uint8_t strings_cnt;
        }
        string_11;
    }
    value;
}

Description:

The snd_switch_t structure describes the switches for a mixer. You can fill this structure by calling snd_ctl_mixer_switch_read().

The members include:

iface

The audio interface associated with the switch.

device

The device number associated with the switch.

channel

Currently only set to “0”.

name

The text name of the switch.

type

The kind of switch. The following types are supported:

SND_SW_TYPE_BOOLEAN

A simple on and off switch. See the enable union member.

SND_TYPE_BYTE

An 8-bit value constrained between a minimum and maximum setting. See the byte union member.

SND_TYPE_WORD

A 16-bit value constrained between a minimum and maximum setting. See the word union member.

SND_TYPE_DWORD

A 32-bit value constrained between a minimum and maximum setting. See the dword union member.

SND_TYPE_LIST

A 32-bit value selected from a list of values. See the list union member. The items_cnt argument is the number of valid items in the array.

SND_TYPE_STRING_11

An array of string selections with a maximum length of 11 bytes. The strings_cnt argument is the number of valid strings in the array. The selection argument is the index of the selected string.

subtype

The switch's subtype. The following types are supported:

SND_SW_SUBTYPE_DEC

Display the value in decimal notation.

SND_SW_SUBTYPE_HEXA

Display the value in hexadecimal notation.

Classification:

QNX Neutrino

See also:

snd_ctl_mixer_switch_read(), snd_ctl_mixer_switch_write()