compilation error requires c++20

[nihui]

in cmakelists.txt, it claims c++17

set(CMAKE_CXX_STANDARD 17)

however, std::source_location is only available from C++20 onwards

In file included from /home/nihui/osd/MMDeploy/csrc/core/status_code.h:11,
                 from /home/nihui/osd/MMDeploy/csrc/core/status_code.cpp:3:
/home/nihui/osd/MMDeploy/csrc/core/utils/source_location.h:9:29: 错误：‘source_location’不是命名空间‘std’中的一个类型名
    9 | using SourceLocation = std::source_location;
      |                             ^~~~~~~~~~~~~
/home/nihui/osd/MMDeploy/csrc/core/utils/source_location.h:9:24: 附注：‘std::source_location’ is only available from C++20 onwards
    9 | using SourceLocation = std::source_location;
      |                        ^

[lzhangzz]

It looks like there is a bug when detecting whether source_location is available.

std::source_location has experimental support in libstdc++ even without C++20 support for quite a while. We tried to detect whether it's available with some macros, however it failed to work on your compiler.

So, what compiler are you using to compile mmdeploy?

[nihui]

fedora 35
gcc 11.2.1