linux U盘格式化

//umount 
 for(i = 0;i < 5;i++)
 {
      ret = system("umount /media/USB\n");
  if(ret == 0)
  {
      ret = 0;
      break;
  }
  else
  {
      fprintf(stderr,"SD Umount try count = %d\n",(i + 1));
  }
  sleep(1);
 }
 sleep(5);
//format 
 sprintf(buffer,"%s /dev/%s\n","mkdosfs",buff);
 printf("3---------------------------------------buffer = %s\n",buffer);
 if(system(buffer) == 0)//success
 {
  ret = 0;
 }else
  {
   ret = -1;
  }
 sleep(5);

//mount
 memset(buffer,'0',sizeof(buffer));
 //sprintf(buffer,"mount -t vfat /dev/%s %s\n",buff,USB_MNT_PATH);
 sprintf(buffer,"mount /dev/%s %s\n",buff,USB_MNT_PATH);
 printf("4---------------------------------------buffer = %s\n",buffer);
 if(system(buffer) == 0)//success
 {
  ret = 0;
 }else
  {
   ret = -1;
  }
 return ret;