os.py 文件源码

def nb_write(fd, buf):
        """Write bytes from buffer `buf` to file descriptor `fd`. Return the
        number of bytes written.

        The file descriptor must be in non-blocking mode.
        """
        hub, event = None, None
        while True:
            try:
                return _write(fd, buf)
            except OSError, e:
                if e.errno not in ignored_errors:
                    raise
                sys.exc_clear()
            if hub is None:
                hub = get_hub()
                event = hub.loop.io(fd, 2)
            hub.wait(event)