<vulkan/vulkan_hash.hpp> included in vulkan.cppm but std::hash specializations are not exported.

[stripe2933]

Looks like Clang can use them, but MSVC can't. Is it intended behavior?

[sharadhr]

I suppose we need to explicitly export the template specialisations. I haven't quite tested them; if you've got a minimum example that'd be great.

[asuessenbach]

@sharadhr If you're looking for some usage of the vk-hash functions, please have a look at the Hash test (Vulkan-Hpp\tests\Hash\Hash.cpp).

[asuessenbach]

@sharadhr Are you working on resolving this issue? Or could you give me some hint how I could do that?

[sharadhr]

I've been looking at it but I am not certain how to proceed. What I've done is write the following in CppStdModule.cpp (essentially copied the contents of Hash.cpp but replaced the #include lines with import), and try to compile it (assuming all CMake options are set correctly).

CppStdModule.cpp.txt

I then see, with cl.exe:

  C:\PROGRA~1\MIB055~1\2022\ENTERP~1\VC\Tools\MSVC\1441~1.341\bin\Hostx64\x64\cl.exe  /nologo /TP -DCLANG_FORMAT_EXECUTABLE=\"R:/Vulkan-Hpp/clang-format.exe\" -DNOMINMAX -DVK_USE_PLATFORM_WIN32_KHR -DVULKAN_HPP_DISPATCH_LOADER_DYNAMIC=1 -DVULKAN_HPP_ENABLE_STD_MODULE -IR:\Vulkan-Hpp -IR:\Vulkan-Hpp\Vulkan-Headers\include -IR:\Vulkan-Hpp\glm -external:IR:\Vulkan-Hpp\vcpkg\installed\x64-windows\include -external:W0 /DWIN32 /D_WINDOWS /EHsc /O2 /Ob1 /DNDEBUG -std:c++latest -MD -Zi /W4 /WX /showIncludes @tests\CppStdModule\CMakeFiles\CppStdModule.dir\CppStdModule.cpp.obj.modmap /Fotests\CppStdModule\CMakeFiles\CppStdModule.dir\CppStdModule.cpp.obj /Fdtests\CppStdModule\CMakeFiles\CppStdModule.dir\ /FS -c R:\Vulkan-Hpp\tests\CppStdModule\CppStdModule.cpp
R:\Vulkan-Hpp\tests\CppStdModule\CppStdModule.cpp(41): error C2512: 'std::hash<vk::Instance>': no appropriate default constructor available
  R:\Vulkan-Hpp\tests\CppStdModule\CppStdModule.cpp(41): note: Invalid aggregate initialization
R:\Vulkan-Hpp\tests\CppStdModule\CppStdModule.cpp(52): error C2512: 'std::hash<vk::FormatFeatureFlags>': no appropriate default constructor available
  R:\Vulkan-Hpp\tests\CppStdModule\CppStdModule.cpp(52): note: Invalid aggregate initialization
  ninja: build stopped: subcommand failed.