Method initialize

tornado/process.py:309–327

Initializes the ``SIGCHLD`` handler. The signal handler is run on an `.IOLoop` to avoid locking issues. Note that the `.IOLoop` used for signal handling need not be the same one used by individual Subprocess objects (as long as the ``IOLoops`` are each running in sep

(cls)

    @classmethod
    def initialize(cls) -> None:
        """Initializes the ``SIGCHLD`` handler.

        The signal handler is run on an `.IOLoop` to avoid locking issues.
        Note that the `.IOLoop` used for signal handling need not be the
        same one used by individual Subprocess objects (as long as the
        ``IOLoops`` are each running in separate threads).

        .. versionchanged:: 5.0
           The ``io_loop`` argument (deprecated since version 4.1) has been
           removed.

        Availability: Unix
        """
        if cls._initialized:
            return
        loop = asyncio.get_event_loop()
        loop.add_signal_handler(signal.SIGCHLD, cls._cleanup)
        cls._initialized = True

    @classmethod
    def uninitialize(cls) -> None: