https://blog.wongcw.com/2019/10/31/php-7-4-%e7%9a%84ffi-%e5%b0%87%e6%94%af%e6%8c%81%e6%9b%b4%e5%a5%bd%e5%9c%b0%e5%9c%a8php-%e4%b8%ad%e4%bd%bf%e7%94%a8c-%e5%87%bd%e6%95%b8-%e6%95%b8%e6%93%9a%e7%b5%90%e6%a7%8b/