linux alsa 播放

#include <stdio.h>
#include <stdlib.h>
#include <alsa/asoundlib.h>

int main() {
    snd_pcm_t *handle;
    snd_pcm_hw_params_t *params;
    unsigned int rate = 44100;
    int dir;
    char *buffer;
    int size, loops;

    /* Open PCM device for playback. */
    if (snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0) < 0) {
        fprintf(stderr, "Unable to open PCM device\n");
        exit(1);
    }

    /* Allocate a hardware parameters object. */
    snd_pcm_hw_params_alloca(&params);

    /* Fill it in with default values. */
    snd_pcm_hw_params_any(handle, params);

    /* Set the desired hardware parameters. */
    snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
    snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE);
    snd_pcm_hw_params_set_rate_near(handle, params, &rate, &dir);
    snd_pcm_hw_params_set_channels(handle, params, 2);

    /* Apply the hardware parameters. */
    snd_pcm_hw_params(handle, params);

    /* Allocate buffer to hold single period. */
    snd_pcm_hw_params_get_period_size(params, &size, &dir);
    buffer = (char *) malloc(size * 4);

    /* Fill the buffer with some data. */
    for (loops = 0; loops < 3; loops++) {
        for (int i = 0; i < size; i++) {
            buffer[i * 4] = 0;       /* Left channel */
            buffer[i * 4 + 1] = 0;   /* Right channel */
            buffer[i * 4 + 2] = 0;   /* Left channel */
            buffer[i * 4 + 3] = 0;   /* Right channel */
        }
        snd_pcm_writei(handle, buffer, size);
    }

    free(buffer);
    snd_pcm_close(handle);
    return 0;
}

gcc -o alsa_playback alsa_playback.c -lasound
./alsa_playback