#include <unistd.h>#include <fcntl.h>#include <sys/types.h>#include <sys/ioctl.h>#include <stdlib.h>#include <stdio.h>#include <linux/soundcard.h>/* 下面的三个参数是跟具体文件相关 * cmd： file 音频文件 * [file pass.wav] =>> pass.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, mono 44100 Hz *　　1. 16位 *　　2. mono为当声道=1, Stereo为立体声=2 *　　3. 44100HZ为频率这个大家都知道，及一秒钟采集或者播放音频的bit数量。 */#define RATE 44100#define SIZE 16#define CHANNELS 1  // 1表示单声道，2为立体/* 缓冲区 */unsigned char buff[RATE * SIZE * CHANNELS / 8]; //buff里面正好放一秒钟的音频int main(){    int fd;    int wavfd; /* wav文件的描述符 */    int arg;   /* ioctl参数 */    int ret;   /* 返回值 */    /* 打开dsp音频设备 */    fd = open("/dev/dsp", O_WRONLY);    if (fd < 0) {        printf("open of /dev/dsp failed");        exit(1);    }    wavfd = open("pass.wav",O_RDONLY);    if (wavfd < 0) {        printf("open of wav failed");        close(fd);        exit(1);    }    /* 设置bit */    arg = SIZE;    ret = ioctl(fd, SOUND_PCM_WRITE_BITS, &arg);    if (ret == -1)         perror("SOUND_PCM_WRITE_BITS ioctl failed");    if (arg != SIZE)         perror("unable to set sample size");    /* 设置channels */    arg = CHANNELS;    ret = ioctl(fd, SOUND_PCM_WRITE_CHANNELS, &arg);    if (ret == -1)        perror("SOUND_PCM_WRITE_CHANNELS ioctl failed");    if (arg != CHANNELS)        perror("unable to set number of channels");    /* 设置rate */    arg = RATE;    ret = ioctl(fd, SOUND_PCM_WRITE_RATE, &arg);    if (ret == -1)        perror("SOUND_PCM_WRITE_WRITE ioctl failed");    /* 从wav文件中读buff大小的内容，然后写入/dev/dsp中，直到文件结束 */　　/* Q：这里我试验时播放了两次，不知道啥情况，如果大家也遇到了请指教。*/    while ((ret = read(wavfd, buff, sizeof(buff))) > 0) {        //printf("read size = %d\n", ret);        write(fd, buff, sizeof(buff));        /* 下面的代码用于在更改播放文件的参数时，播放掉缓冲区内的内容 */        ret = ioctl(fd, SOUND_PCM_SYNC, 0);        if (ret == -1)            perror("SOUND_PCM_SYNC ioctl failed");    }    close(fd);    close(wavfd);}下面是封装的接口可以直接拿过来使用：void play_audio(int rate, int bits, int channels, char *filename){    int fd;    int wavfd; /* wav文件的描述符 */    int arg;   /* ioctl arg */    int ret;   /* return value */    unsigned char buff[rate * bits * channels / 8]; //buff里面正好放一秒钟的音频    /* open device */    fd = open("/dev/dsp", O_WRONLY);    if (fd < 0) {        printf("open of /dev/dsp failed");        exit(1);    }    wavfd = open(filename, O_RDONLY);    if (wavfd < 0) {        printf("open of wav failed");        close(fd);        exit(1);    }    /* set bits */    arg = bits;    ret = ioctl(fd, SOUND_PCM_WRITE_BITS, &arg);    if (ret == -1)         perror("SOUND_PCM_WRITE_BITS ioctl failed");    if (arg != SIZE)         perror("unable to set sample size");    /* set channels */    arg = channels;    ret = ioctl(fd, SOUND_PCM_WRITE_CHANNELS, &arg);    if (ret == -1)        perror("SOUND_PCM_WRITE_CHANNELS ioctl failed");    if (arg != CHANNELS)        perror("unable to set number of channels");    /* set rate */    arg = rate;    ret = ioctl(fd, SOUND_PCM_WRITE_RATE, &arg);    if (ret == -1)        perror("SOUND_PCM_WRITE_WRITE ioctl failed");    /* 从wav文件中读buff大小的内容，然后写入/dev/dsp中，直到文件结束 */    while ((ret = read(wavfd, buff, sizeof(buff))) > 0) {        printf("read size = %d\n", ret);        write(fd, buff, sizeof(buff));        /* 下面的代码用于在更改播放文件的参数时，播放掉缓冲区内的内容 */        ret = ioctl(fd, SOUND_PCM_SYNC, 0);        if (ret == -1)            perror("SOUND_PCM_SYNC ioctl failed");    }    close(fd);    close(wavfd);}