When using VULKAN_HPP_ENABLE_EXPERIMENTAL_CPP20_MODULES=ON with CMake 3.27.0 or 3.27.1,
you will get a very confusing error message:
```
CMake Error at CMakeLists.txt:346 (target_sources):
target_sources File set TYPE may only be "HEADERS"
```
This is because the value of `CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API`
is not update to the correct value, disabling all experimental CMake
features.
This PR adds the value for 3.27.X and triggers an error for higher CMake
versions where this feature needs to be revised and
CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API if the feature is still
experimental.
The error message will look similar to this one (simulated for CMake
3.27.1)
```
CMake Error at CMakeLists.txt:30 (message):
VULKAN_HPP_ENABLE_EXPERIMENTAL_CPP20_MODULES is currently not supported for
CMake version 3.27.1! To add support inform yourself about the state of the
feature at
https://github.com/Kitware/CMake/blob/master/Help/dev/experimental.rst and
add the corresponding value of CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API to
Vulkan-Hpp's CMakeLists.txt
```
* Bug fixes for C++20 module
- Removed nested `export` keyword for `vk::raii` namespace in C++ module file
- Fixed macro in `vulkan.cppm` for `vk::DynamicLoader`: changed from `VULKAN_HPP_DYNAMIC_LOADER_TOOL` to `VULKAN_HPP_ENABLE_DYNAMIC_LOADER_TOOL`
- Moved VulkanHppModule declaration before generator
- Fixed `CMakeLists.txt` for `Cpp20Modules` executable target
* Use `VULKAN_HPP_CONSTEXPR_INLINE` for constants in `vulkan.hpp`
- Added VULKAN_HPP_CONSTEXPR_INLINE macro definition
- Allow external linkage for these constants in C++17 and later
* feat: exported vk::raii types in vulkan.ixx, with a small test
* feat: *almost* complete vulkan.ixx; missing functions in vulkan_funcs.hpp and constexpr auto defines
* Exported free functions in `vulkan_funcs.hpp` in `vulkan.ixx`
* Completed vulkan.ixx
Exported all types, structs, functions; need to handle anonymous namespace and getDispatchLoaderStatic()
* Moved `vk::anon-namespace::throwResultException` to `vk::detail::throwResultException` to solve linking errors
* Made `vk::getDispatchLoaderStatic` not `static`
`static`in namespace/global scope has to do with internal/external linkage, and not lifetime
* Fixed debug assert fail in `generateCppModuleStructUsings`
* Removed references to `.cppm`
* Formatting and versioning changes
- CMake version handling simplified
- vulkan.ixx includes new structs from new versions
- vulkan.hpp and vulkan_raii.hpp reformatted with clang-format 14
* Removed extraneous includes
- std::optional -> std::string::empty
- std::filesystem was unused
* Fixed constexpr function and value generation
- 'c' prefix removed
- Constants casing fixed
- Types for constants fixed
- Constants assigned to macros
- Ordering of constants and consteval functions fixed
* Moved constexprs to `vulkan.hpp`
- Added corresponding `using` statements to `vulkan.ixx`
- Changed `consteval auto(auto)` functions into templated SFINAE `constexpr` functions
* Formatting, signposting, misc fixes
- Added newlines around macro guards
- Added signposting comments for relevant groups of `using`-statements in `vulkan.ixx`
- Guarded createInstanceUnique with macro guard
- Use m_handles.at("").commands for Funcs
* Changed module file extension to `.cppm`
- It follows the rest of the project convention; `ixx` looks really weird next to `.hpp` and `.cpp`
- CMake transparently handles any extension anyway
* Added `VULKAN_HPP_DEFAULT_DISPATCH_LOADER_DYNAMIC_STORAGE` to `vulkan.cppm`
* Added format traits and extension inspections
- Straightforward, since everything is hard-coded
* Added documentation about Vulkan-Hpp C++ module
- Compiler requirements
- CMake compilation
- Command-line examples
* Added vulkan_hash.hpp
- No need for `using`, since all declarations are template specialisations of existing `std` objects
* Documentation and comment fixes
- Removed extraneous CMake version comments
- Documentation about default dynamic dispatcher with the module
- Comment updates in the source code
* Moved constexpr defines and using statements
- Moved to after resultUsings in both vulkan.hpp and vulkan.cppm
- Also split up constexprDefinesAndUsings
- Used const_cast for constexprDefines()
* Used std::string instead of std::stringstream
- Some changes also in previous commit
- Also removed overly-clever ranges algorithms
* Simplified protection generation
- Removed `generateNotProtection`
- Added optional `bool` parameter to `generateProtection` for `#if !defined( ... )`
* Simplified Cpp20Modules CMakeLists
- Made C++ standard and libraries into parameters
- Removed FindVulkan call; already done
* `constexpr` generation fixed
- Made all generating functions `const`
- Removed typos and extra comments
- Extracted out filtering functionality into separate functions
* Simplified defines partition generation
- Added `DefinesPartition` struct as a member variable
- Added non-const function to write to the above in `readTypeDefines`
- Removed previous implementation that made many copies
* Added `generateUsingsAndProtection` lambda to RAII name generation
* Moved around `partitionDefines` to make more sense
- called once at the end of the constructor
- edited comments
* Updated headers to 1.3.255
* Removed std::ranges and ranges view adaptors
- CI isn't passing with them
* Fixed constexpr functions for C++11 and C++14
- Removed `enable_if_t` and `is_integral_v`
- Changed `auto` return type into `uint32_t`
---------
Co-authored-by: Sharadh Rajaraman <r.sharadh@yahoo.com.sg>