Linux 下 列出所有alsa设备代码
static void device_list(void)
{
snd_ctl_t *handle;
int card, err, dev, idx;
snd_ctl_card_info_t *info;
snd_pcm_info_t *pcminfo;
snd_ctl_card_info_alloca(&info);
snd_pcm_info_alloca(&pcminfo);
card = -1;
if (snd_card_next(&card) < 0 || card < 0) {
error(_("no soundcards found..."));
return;
}
printf(_("**** List of %s Hardware Devices ****\n"),
snd_pcm_stream_name(stream));
while (card >= 0) {
char name[32];
sprintf(name, "hw:%d", card);
if ((err = snd_ctl_open(&handle, name, 0)) < 0) {
error("control open (%i): %s", card, snd_strerror(err));
goto next_card;
}
if ((err = snd_ctl_card_info(handle, info)) < 0) {
error("control hardware info (%i): %s", card, snd_strerror(err));
snd_ctl_close(handle);
goto next_card;
}
dev = -1;
while (1) {
unsigned int count;
if (snd_ctl_pcm_next_device(handle, &dev)<0)
error("snd_ctl_pcm_next_device");
if (dev < 0)
break;
snd_pcm_info_set_device(pcminfo, dev);
snd_pcm_info_set_subdevice(pcminfo, 0);
snd_pcm_info_set_stream(pcminfo, stream);
if ((err = snd_ctl_pcm_info(handle, pcminfo)) < 0) {
if (err != -ENOENT)
error("control digital audio info (%i): %s", card, snd_strerror(err));
continue;
}
printf(_("card %i: %s [%s], device %i: %s [%s]\n"),
card, snd_ctl_card_info_get_id(info), snd_ctl_card_info_get_name(info),
dev,
snd_pcm_info_get_id(pcminfo),
snd_pcm_info_get_name(pcminfo));
count = snd_pcm_info_get_subdevices_count(pcminfo);
printf( _(" Subdevices: %i/%i\n"),
snd_pcm_info_get_subdevices_avail(pcminfo), count);
for (idx = 0; idx < (int)count; idx++) {
snd_pcm_info_set_subdevice(pcminfo, idx);
if ((err = snd_ctl_pcm_info(handle, pcminfo)) < 0) {
error("control digital audio playback info (%i): %s", card, snd_strerror(err));
} else {
printf(_(" Subdevice #%i: %s\n"),
idx, snd_pcm_info_get_subdevice_name(pcminfo));
}
}
}
snd_ctl_close(handle);
next_card:
if (snd_card_next(&card) < 0) {
error("snd_card_next");
break;
}
}
}