alsa-lib/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;
}