https://blog.youkuaiyun.com/JuanA1/article/details/6849120
https://blog.youkuaiyun.com/fantasy_wxe/article/details/8066551?utm_source=blogxgwz7
http://www.unixwiz.net/techtips/gnu-c-attributes.html
https://blog.youkuaiyun.com/hpu11/article/details/53326609
https://blog.youkuaiyun.com/solosure/article/details/6144954