Alsa : list all device, name and description

ref:

• linux:找到我可以使用ALSA播放PCM的所有設備

就是.. 在使用 alsalib, opendevice 時，要找到要用的 device, 利用 snd library ，可以enumerate 所有 alsa
為了防止網站消失，把他的 code copy 下來...

#include <stdio.h>
#include <limits.h>
#include <stdlib.h>
#include <unistd.h>
#include <alsa/asoundlib.h>
void listdev(char *devname)
{
    char** hints;
    int    err;
    char** n;
    char*  name;
    char*  desc;
    char*  ioid;
    /* Enumerate sound devices */
    err = snd_device_name_hint(-1, devname, (void***)&hints);
    if (err != 0) {
        fprintf(stderr, "*** Cannot get device names\n");
        exit(1);
    }
    n = hints;
    while (*n != NULL) {
        name = snd_device_name_get_hint(*n, "NAME");
        desc = snd_device_name_get_hint(*n, "DESC");
        ioid = snd_device_name_get_hint(*n, "IOID");
        printf("Name of device: %s\n", name);
        printf("Description of device: %s\n", desc);
        printf("I/O type of device: %s\n", ioid);
        printf("\n");
        if (name && strcmp("null", name)) free(name);
        if (desc && strcmp("null", desc)) free(desc);
        if (ioid && strcmp("null", ioid)) free(ioid);
        n++;
    }
    //Free hint buffer too
    snd_device_name_free_hint((void**)hints);
}
int main(void)
{
    printf("PCM devices:\n");
    printf("\n");
    listdev("pcm");
    printf("MIDI devices:\n");
    printf("\n");
    listdev("rawmidi");
    return 0;
}

make 的時候加上 -lasound 來 link alsa library

 sudo apt-get install libasound2-dev