Hello,

Starting to write an ALSA app and trying to just list sound card info. The type "snd_ctl_card_info_t" doesn't seem to resolve by just including <alsa/asoundlib.h>. This type is needed for me to call snd_ctl_card_info(). OS is Ubuntu 11.10 with libasound2-dev installed. What am I doing wrong? Code is below:

#include <stdio.h> #include <alsa/asoundlib.h>

void print_card_info(snd_ctl_card_info_t info) { printf("Card #=%d, id=%s, driver=%s, name=%s, longname=%s, mixername=%s, components=%s\n", info.card, info.id, info.driver, info.name, info.longname, info.mixername, info.components); }

int main(int argc, char **argv) { int card = -1; char cardascii[3]; char *name, *longname; snd_ctl_t *handle; snd_ctl_card_info_t info;

while (snd_card_next(&card) >= 0) { if (card < 0) { printf("No more cards!\n"); break; } printf("Card %d\n", card); if (snd_card_get_name(card, &name)) { printf("Error getting card %d's name, skipping\n", card); continue; } printf("Name = %s\n", name); if (snd_card_get_longname(card, &longname)) { printf("Error getting card %d's long name, skipping\n", card); continue; } printf("Long name = %s\n", longname); snprintf(cardascii, sizeof(cardascii), "%d", card); if (snd_ctl_open(&handle, cardascii, 0)) { printf("Error opening card #%d, skipping\n", card); continue; } if (snd_ctl_card_info(handle, &info)) { printf("Error getting info for card #%d, skipping\n", card); snd_ctl_close(handle); continue; } print_card_info(info); snd_ctl_close(handle); }

return 0; }

$ make mkdir .deps cc -O2 -std=gnu99 -Wall -Wextra -pedantic -g -c -DPREFIX="/usr/local" -Wp,-MD,.deps/list.d -o list.o list.c list.c:4:42: error: parameter 1 (âinfoâ) has incomplete type list.c: In function âprint_card_infoâ: list.c:4:42: warning: unused parameter âinfoâ [-Wunused-parameter] list.c: In function âmainâ: list.c:16:22: error: storage size of âinfoâ isnât known list.c:16:22: warning: unused variable âinfoâ [-Wunused-variable] list.c:10:14: warning: unused parameter âargcâ [-Wunused-parameter] list.c:10:27: warning: unused parameter âargvâ [-Wunused-parameter] make: *** [list.o] Error 1