Method _try_cleanup_process

python/python3/tornado/process.py:346–355

(cls, pid: int)

    @classmethod
    def _try_cleanup_process(cls, pid: int) -> None:
        try:
            ret_pid, status = os.waitpid(pid, os.WNOHANG)  # type: ignore
        except ChildProcessError:
            return
        if ret_pid == 0:
            return
        assert ret_pid == pid
        subproc = cls._waiting.pop(pid)
        subproc.io_loop.add_callback_from_signal(subproc._set_returncode, status)

    def _set_returncode(self, status: int) -> None:
        if sys.platform == "win32":