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 */
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);
	}

	/* pass the remaining samples, otherwise they're dropped in close */
	err = snd_pcm_drain(handle);
	if (err < 0)
		printf("snd_pcm_drain failed: %s\n", snd_strerror(err));
	snd_pcm_close(handle);
	return 0;
}