_test_multiprocessing.py 文件源码

def get_high_socket_fd(self):
        if WIN32:
            # The child process will not have any socket handles, so
            # calling socket.fromfd() should produce WSAENOTSOCK even
            # if there is a handle of the same number.
            return socket.socket().detach()
        else:
            # We want to produce a socket with an fd high enough that a
            # freshly created child process will not have any fds as high.
            fd = socket.socket().detach()
            to_close = []
            while fd < 50:
                to_close.append(fd)
                fd = os.dup(fd)
            for x in to_close:
                os.close(x)
            return fd