[MSVC][/std:c++latest] Ppsspp failed to build with msvc due to error C2679, error C2665 on Windows

[fangzhouxia]

Game or games this happens in

None

What area of the game / PPSSPP

Hi all,
PPsspp fails to build on MSVC due to error C2665, error C2679. Could you help look?
we use commit is b42f6d7.
Repro steps

1. git clone --recursive https://github.com/hrydgard/ppsspp.git F:\gitP\hrydgard\ppsspp_new
2. set CL= /std:c++latest
3. F:\gitP\hrydgard\ppsspp_new
4. makir build_amd64
5. cd F:\gitP\hrydgard\ppsspp_new\build_amd64
6. msbuild /m /p:Platform=x64 /p:Configuration=Release ../Windows/PPSSPP.sln /t:Rebuild /p:OutDir=F:\gitP\hrydgard\ppsspp_new\build_amd64

error info
F:\gitP\hrydgard\ppsspp\ext\armips\ext\tinyformat\tinyformat.h(342,9): error C2679: binary '<<': no operator found which takes a right-hand operand of type 'const T' (or there is no acceptable conversion) [F:\gitP\hrydgard\ppsspp\ext\libarmips.vcxproj]
F:\gitP\hrydgard\ppsspp\ext\armips\Core\Common.cpp(53,9): error C2665: 'std::basic_string<char,std::char_traits,std::allocator>::basic_string': no overloaded function could convert all the argument types [F:\gitP\hrydgard\ppsspp\ext\libarmips.vcxproj]

What should happen

Build successfully

Logs

build.log

Platform

Windows

Mobile phone model or graphics card

None

PPSSPP version affected

None

Last working version

None

Graphics backend (3D API)

Other

Checklist

• Test in the latest git build in case it's already fixed.
• Search for other reports of the same issue.
• Try resetting settings or older versions and include if the issue is related.
• Try without any cheats and without loading any save states.
• Include logs or screenshots of issue.

[hrydgard]

Seems like another one where it's building with a too old C++ standard, for some reason?

[unknownbrackets]

Well, I guess maybe std:c++latest would use c++20? This seems to be a tinyformat issue (dependency of armips), so two layers of indirection from ppsspp itself.

-[Unknown]

[hrydgard]

@Kingcom just fyi

[hrydgard]

Or maybe only an old version of MSVC is installed, so latest isn't actually that new?

[unknownbrackets]

Well, the build log says Visual Studio 2019. It also says warning C4996: 'std::is_pod<T>': warning STL4025: std::is_pod and std::is_pod_v are deprecated in C++20.

-[Unknown]

[Kingcom]

All of the errors seem to be about std::basic_string<char8_t,std::char_traits<char8_t>,std::allocator<char8_t>>, or std::u8string in short. This is only available in C++20. I'm not able to reproduce this with VS 2022 (v17.0.4 per vcvars), so my guess is that the version used does not have complete support for char8_t.

[Kingcom]

Ah, this only happens if ARMIPS_USE_STD_FILESYSTEM is set... so only when it uses Microsoft's std::filesystem implementation and not ghc.

Either way, C++20 is not the most backwards compatible of standards, is there any reason for not sticking to what ppsspp defines?