如何判断 g++ 和 clang 可用的 C++ 版本

Question

够简单的。我可以通过传递 --std 选项来选择 g++ 或 clang 的版本。如何让 g++ 或 clang 显示哪些版本可用？

Answer 1

对于叮当声：

$ touch 1.c 1.cpp;clang -std=x 1.c 1.cpp
error: invalid value 'x' in '-std=x'
note: use 'c89', 'c90', or 'iso9899:1990' for 'ISO C 1990' standard
note: use 'iso9899:199409' for 'ISO C 1990 with amendment 1' standard
note: use 'gnu89' or 'gnu90' for 'ISO C 1990 with GNU extensions' standard
note: use 'c99' or 'iso9899:1999' for 'ISO C 1999' standard
note: use 'gnu99' for 'ISO C 1999 with GNU extensions' standard
note: use 'c11' or 'iso9899:2011' for 'ISO C 2011' standard
note: use 'gnu11' for 'ISO C 2011 with GNU extensions' standard
note: use 'c17', 'iso9899:2017', 'c18', or 'iso9899:2018' for 'ISO C 2017' standard
note: use 'gnu17' or 'gnu18' for 'ISO C 2017 with GNU extensions' standard
note: use 'c2x' for 'Working Draft for ISO C2x' standard
note: use 'gnu2x' for 'Working Draft for ISO C2x with GNU extensions' standard
error: invalid value 'x' in '-std=x'
note: use 'c++98' or 'c++03' for 'ISO C++ 1998 with amendments' standard
note: use 'gnu++98' or 'gnu++03' for 'ISO C++ 1998 with amendments and GNU extensions' standard
note: use 'c++11' for 'ISO C++ 2011 with amendments' standard
note: use 'gnu++11' for 'ISO C++ 2011 with amendments and GNU extensions' standard
note: use 'c++14' for 'ISO C++ 2014 with amendments' standard
note: use 'gnu++14' for 'ISO C++ 2014 with amendments and GNU extensions' standard
note: use 'c++17' for 'ISO C++ 2017 with amendments' standard
note: use 'gnu++17' for 'ISO C++ 2017 with amendments and GNU extensions' standard
note: use 'c++20' for 'ISO C++ 2020 DIS' standard
note: use 'gnu++20' for 'ISO C++ 2020 DIS with GNU extensions' standard

对于 gcc，它存在于 gcc -v --help 中。