cards.c File Reference

Basic Soundcard Operations. More...

Functions
int	snd_card_load (int card)
	Try to load the driver for a card.
int	snd_card_next (int *rcard)
	Iterate over physical sound cards.
int	snd_card_get_index (const char *string)
	Convert a card string to the card index.
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.

Detailed Description

Basic Soundcard Operations.

Author

Jaroslav Kysela perex.nosp@m.@per.nosp@m.ex.cz

Date

1998-2001

Function Documentation

snd_card_get_index()

int snd_card_get_index

(

const char *

string

)

Convert a card string to the card index.

This works only for physical sound cards, not for virtual cards.

Parameters

string

A string identifying the card.

Returns

The index of the card. On error, a a negative error code is returned.

The accepted formats for "string" are:

• The index of the card (as listed in /proc/asound/cards), given as string
• The ID of the card (as listed in /proc/asound/cards)
• The control device name (like /dev/snd/controlC0)

snd_card_get_longname()

int snd_card_get_longname	(	int	card,
		char **	name )

Obtain the card long name.

Parameters

card	Index of the card.
name	Result - card long name corresponding to card index.

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.

snd_card_get_name()

int snd_card_get_name	(	int	card,
		char **	name )

Obtain the card name.

Parameters

card	The index of the card.
name	Result - card name corresponding to card index.

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.

snd_card_load()

int snd_card_load

(

int

card

)

Try to load the driver for a card.

Parameters

card	Card index.

Returns

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

snd_card_next()

int snd_card_next

(

int *

rcard

)

Iterate over physical sound cards.

This function takes the index of a physical sound card and sets it to the index of the next card. If index is -1, it is set to the index of the first card. After the last card, the index is set to -1.

For example, if you have 2 sound cards (with index 0 and 1), the index will be modified as follows:

• -1 --> 0
• 0 --> 1
• 1 --> -1

This does not work for virtual sound cards.

Parameters

rcard

Index of current card. The index of the next card is stored here.

Returns

zero if success, otherwise a negative error code.