threading.py 文件源码

def start(self):
        if not self.__initialized:
            raise RuntimeError("thread.__init__() not called")
        if self.__started.is_set():
            raise RuntimeError("threads can only be started once")
        if __debug__:
            self._note("%s.start(): starting thread", self)
        with _active_limbo_lock:
            _limbo[self] = self
        try:
            _start_new_thread(self.__bootstrap, ())
        except Exception:
            with _active_limbo_lock:
                del _limbo[self]
            raise
        self.__started.wait()