serialposix.py 文件源码

def out_waiting(self):
        """Return the number of bytes currently in the output buffer."""
        #~ s = fcntl.ioctl(self.fd, termios.FIONREAD, TIOCM_zero_str)
        s = fcntl.ioctl(self.fd, TIOCOUTQ, TIOCM_zero_str)
        return struct.unpack('I', s)[0]