select.py 文件源码

def register(self, fd, events):
        if fd in self.read_fds or fd in self.write_fds or fd in self.error_fds:
            raise IOError("fd %s already registered" % fd)
        if events & IOLoop.READ:
            self.read_fds.add(fd)
        if events & IOLoop.WRITE:
            self.write_fds.add(fd)
        if events & IOLoop.ERROR:
            self.error_fds.add(fd)
            # Closed connections are reported as errors by epoll and kqueue,
            # but as zero-byte reads by select, so when errors are requested
            # we need to listen for both read and error.
            # self.read_fds.add(fd)