//======================================================================
//      speaker.cpp -- small application that reads audio samples 
//        from standar output and writes them to the audio device.
// Author: Agustin J. Gonzalez
// October 2002
//======================================================================

#include <stdio.h>
#include <stdlib.h>

// open requires
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
 
// Linux IOCTL and soundcard
#include <sys/ioctl.h>
#include <linux/soundcard.h>

// close requires:
#include <unistd.h>

// errno
#include <errno.h>

int main(int argc, char * argv[]) 
{
  int fd, value, nSamples;
  char buff[256];
  
  printf("usage: %s [sample rate in Hz]\n", argv[0]);
  
  if ((fd = open("/dev/dsp", O_WRONLY)) < 0) {
    if ((errno == EINTR) || (errno == EBUSY)) {
      printf("Audio device is Busy...  \n");
      exit(-1);
    }
    printf("Error opening audio device ... \n");
    exit(-1);
  }
  
  // Set to Mono
  value=0;
  ioctl(fd,SNDCTL_DSP_STEREO,&value);
  
  // Set Audio format to the 8 bits per sample.
  value=AFMT_S8;
  ioctl(fd,SNDCTL_DSP_SETFMT, &value);
  
  // Set sample rate
  if (argc==2) value= atoi(argv[1]);
  else value=8000;
  ioctl(fd,SNDCTL_DSP_SPEED, &value);
  
  while(1) {
    nSamples=read(0, buff, sizeof(buff));
    write(fd, buff, nSamples);
  }
}