p6.9.c

linux编程源代码,其中是由大量的实例

#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <linux/soundcard.h>

#define Audio_Device "/dev/dsp"
/*
  the following feature will be different according to different sound file,
  use file command to get detail information about the wave file
*/
#define Sample_Size 32  /*there're two kinds of bits, 8 bits and 16 bits */
#define Sample_Rate 220050 /* sampling rate */

int play_sound(char *filename){
  struct stat stat_buf;
  unsigned char *buf = NULL;
  int handler,fd;
  int result;
  int arg,status;

/*
  open the sound file and get related information,read the whole file 
  into the buffer memory
*/
  fd = open(filename, O_RDONLY);
  if (fd<0)
      return -1;

  if (fstat(fd, &stat_buf)) {
     close(fd);
     return -1;
 }
  if (!stat_buf.st_size) {
	close(fd);
	return -1;
  }

  buf = malloc(stat_buf.st_size);
  if (!buf) {
	close(fd);
	return -1;
  }

  if (read(fd, buf, stat_buf.st_size) < 0) {
	free(buf);
	close(fd);
	return -1;
  }

 /*
  open the sound card device and set the sound card hardware options
 */
  handler = open(Audio_Device, O_WRONLY);
  if (handler == -1) {
	perror("open Audio_Device fail");
	return -1;
 }
 
  arg=Sample_Rate;
  status=ioctl(handler,SOUND_PCM_WRITE_RATE,&arg);
  if(status==-1){
        perror("error from SOUND_PCM_WRITE_RATE ioctl");
        return -1;
}

  arg=Sample_Size;
  status=ioctl(handler,SOUND_PCM_WRITE_BITS,&arg);
  if(status==-1){
	  perror("error from SOUND_PCM_WRITE_BITS ioctl");
	  return -1;
  }

  result=write(handler,buf,stat_buf.st_size);
  if(result==-1){
       perror("Fail to play the sound!");
       return -1;
  }


  free(buf);
  close(fd);
  close(handler);
  return result;
}


void main(void)
{
  play_sound("/home/program/a.mp3");
}