wordpress 副标题调用郑州seo外包顾问热狗

实际工作中，可能会遇到c++的一些高级特性，例如std::invoke，此函数是c++17才引入的，如何判断当前的gcc是否支持c++17呢，这里提供两种办法。
1.根据gcc的版本号来推断
gcc --version，可以查看版本号，笔者的电脑，gcc的版本号是8.3.0，然后查看8.3.0是什么时候发布的，查出是2019年发布的，从而推断出是支持，但是不是十分肯定，所以接着看第二种方法
2.直接man gcc

上图中，红色方框-std=表示支持的标准项，可以看到c11,c17之类的

centos 本身自带的版本是不支持到C17的。截取 man gcc如下

 -std=Determine the language standard.   This option is currently only supported when compiling C orC++.The compiler can accept several base standards, such as c90 or c++98, and GNU dialects of thosestandards, such as gnu90 or gnu++98.  When a base standard is specified, the compiler accepts allprograms following that standard plus those using GNU extensions that do not contradict it.  Forexample, -std=c90 turns off certain features of GCC that are incompatible with ISO C90, such asthe "asm" and "typeof" keywords, but not other GNU extensions that do not have a meaning in ISOC90, such as omitting the middle term of a "?:" expression. On the other hand, when a GNU dialectof a standard is specified, all features supported by the compiler are enabled, even when thosefeatures change the meaning of the base standard.  As a result, some strict-conforming programsmay be rejected.  The particular standard is used by -Wpedantic to identify which features areGNU extensions given that version of the standard. For example -std=gnu90 -Wpedantic warns aboutC++ style // comments, while -std=gnu99 -Wpedantic does not.A value for this option must be provided; possible values arec90c89iso9899:1990Support all ISO C90 programs (certain GNU extensions that conflict with ISO C90 aredisabled). Same as -ansi for C code.iso9899:199409ISO C90 as modified in amendment 1.c99c9xiso9899:1999iso9899:199xISO C99.  Note that this standard is not yet fully supported; see<http://gcc.gnu.org/c99status.html> for more information.  The names c9x and iso9899:199x aredeprecated.c11c1xiso9899:2011ISO C11, the 2011 revision of the ISO C standard.  Support is incomplete and experimental.The name c1x is deprecated.gnu90gnu89GNU dialect of ISO C90 (including some C99 features). This is the default for C code.gnu99gnu9xGNU dialect of ISO C99.  When ISO C99 is fully implemented in GCC, this will become thedefault.  The name gnu9x is deprecated.gnu11gnu1xGNU dialect of ISO C11.  Support is incomplete and experimental.  The name gnu1x isdeprecated.c++98c++03The 1998 ISO C++ standard plus the 2003 technical corrigendum and some additional defectreports. Same as -ansi for C++ code.gnu++98gnu++03GNU dialect of -std=c++98.  This is the default for C++ code.c++11c++0xThe 2011 ISO C++ standard plus amendments.  Support for C++11 is still experimental, and maychange in incompatible ways in future releases.  The name c++0x is deprecated.gnu++11gnu++0xGNU dialect of -std=c++11. Support for C++11 is still experimental, and may change inincompatible ways in future releases.  The name gnu++0x is deprecated.c++1yThe next revision of the ISO C++ standard, tentatively planned for 2017.  Support is highlyexperimental, and will almost certainly change in incompatible ways in future releases.gnu++1yGNU dialect of -std=c++1y.  Support is highly experimental, and will almost certainly changein incompatible ways in future releases.