Finding all the devices I can use to play PCM with ALSA

Question

I use ALSA to play PCM samples. I open the PCM stream with this function:

int snd_pcm_open(snd_pcm_t** pcmp,
        const char* name,
        snd_pcm_stream_t stream,
        int mode);

I'm currently using "default" as the name parameter. I would like to be able to choose other devices. What I cannot understand is how I can determine what are the names of the other available devices.

I attached a USB microphone to my system and aplay and amixer seems to detect the new device. How do I determine the name of that device? Is there any ALSA function to get a list of available devices with their respective names?

Answer 1

I think you can use snd_device_name_hint for enumerating devices. Here is an example. Beware that I haven't compiled it !

char **hints;
/* Enumerate sound devices */
int err = snd_device_name_hint(-1, "pcm", (void***)&hints);
if (err != 0)
   return;//Error! Just return

char** n = hints;
while (*n != NULL) {

    char *name = snd_device_name_get_hint(*n, "NAME");

    if (name != NULL && 0 != strcmp("null", name)) {
        //Copy name to another buffer and then free it
        free(name);
    }
    n++;
}//End of while

//Free hint buffer too
snd_device_name_free_hint((void**)hints);