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//Æô¶¯ÐźÅÇý¶¯»úÖÆ
signal(SIGIO, input_handler);//ÈÃinput_handler()´¦ÀíSIGIOÐźÅ
fcntl(fd, F_SETOWN, getpid());//ÉèÖñ¾½ø³ÌΪSTDIN_FILENOÎļþµÄÓµÓÐÕߣ¬ÈÃÄÚºËÖªµÀ½«Ðźŷ¢¸ø±¾½ø³Ì
oflags = fcntl(fd, F_GETFL);//ÏÂÃæÁ½¾ä£ºÉèÖÃFASYNC±êÖ¾£¬Æô¶¯Ò첽֪ͨ±êÖ¾
fcntl(fd, F_SETFL, oflags | FASYNC); 
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struct xxx_dev
{
Struct cdev cdev;
……
Struct fasync_struct *async_queue;
}
 
 
Int fasync_helper(int fd, struct file *filp, int mode, struct fasync_struct **fa);
 
Void kill_fasync(struct fasync_struct **fa, int sig, int band);
 
static int globalfifo_fasync(int fd, struct file *filp, int mode)
{
    struct globalfifo_dev *dev = filp->private_data;
    return fasync_helper(fd, filp, mode, &dev->async_queue);
}
 
static ssize_t globalfifo_write(struct file *filp, const char __user *buf,
  size_t count, loff_t *ppos)
{
    struct globalfifo_dev *dev = filp->private_data; //»ñµÃÉ豸½á¹¹ÌåÖ¸Õë
    ……
   
    if (dev->async_queue)
       kill_fasync(&dev->async_queue, SIGIO, POLL_IN);
   
    ret = count;
  }
 
int globalfifo_release(struct inode *inode, struct file *filp)
{
 
   globalfifo_fasync( - 1, filp, 0);
   return 0;
}
 
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