/* * Copyright (C) 2021 Alibaba Group Holding Limited * Author: LuChongzhi * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include #include #include union { struct cmsghdr cm; // control msg char ctl[CMSG_SPACE(sizeof(int))]; // the pointer of char } ctl_un;