ALSA project - the C library reference: /test/pcm_min.c

# /test/pcm_min.c

    /*
     *  This extra small demo sends a random samples to your speakers.
     */

    #include "../include/asoundlib.h"

    static char *device = "default";                        /* playback device */

    snd_output_t *output = NULL;
    unsigned char buffer[16*1024];                          /* some random data */

    int main(void)
    {
            int err;
            unsigned int i;
            snd_pcm_t *handle;
            snd_pcm_sframes_t frames;

            for (i = 0; i < sizeof(buffer); i++)
                    buffer[i] = random() & 0xff;

            if ((err = snd_pcm_open(&handle, device, SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
                    printf("Playback open error: %s\n", snd_strerror(err));
                    exit(EXIT_FAILURE);
            }
            if ((err = snd_pcm_set_params(handle,
                                          SND_PCM_FORMAT_U8,
                                          SND_PCM_ACCESS_RW_INTERLEAVED,
                                          1,
                                          48000,
                                          1,
                                          500000)) < 0) {   /* 0.5sec */
                    printf("Playback open error: %s\n", snd_strerror(err));
                    exit(EXIT_FAILURE);
            }

            for (i = 0; i < 16; i++) {
                    frames = snd_pcm_writei(handle, buffer, sizeof(buffer));
                    if (frames < 0)
                            frames = snd_pcm_recover(handle, frames, 0);
                    if (frames < 0) {
                            printf("snd_pcm_writei failed: %s\n", snd_strerror(frames));
                            break;
                    }
                    if (frames > 0 && frames < (long)sizeof(buffer))
                            printf("Short write (expected %li, wrote %li)\n", (long)sizeof(buffer), frames);
            }

            snd_pcm_close(handle);
            return 0;
    }

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