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Diffstat (limited to 'Help/dev/experimental.rst')
| -rw-r--r-- | Help/dev/experimental.rst | 41 |
1 files changed, 30 insertions, 11 deletions
diff --git a/Help/dev/experimental.rst b/Help/dev/experimental.rst index c97d542149..c7581e85cc 100644 --- a/Help/dev/experimental.rst +++ b/Help/dev/experimental.rst @@ -57,17 +57,36 @@ dependency scanning. This is similar to the Fortran modules support, but relies on external tools to scan C++20 translation units for module dependencies. The approach is described by Kitware's `D1483r1`_ paper. -The ``CMAKE_EXPERIMENTAL_CXX_MODULE_DYNDEP`` variable can be set to ``1`` -in order to activate this undocumented experimental infrastructure. This -is **intended to make the functionality available to compiler writers** so -they can use it to develop and test their dependency scanning tool. -The ``CMAKE_EXPERIMENTAL_CXX_SCANDEP_SOURCE`` variable must also be set -to tell CMake how to invoke the C++20 module dependency scanning tool. - -MSVC 19.34 (provided with Visual Studio 17.4) and above contains the support -that CMake needs and has these variables already set up as required and only -the UUID and the ``CMAKE_EXPERIMENTAL_CXX_MODULE_DYNDEP`` variables need to be -set. +In order to activate CMake's experimental support for C++20 module +dependencies, set the following variables: + +``CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API`` + Set this to the UUID documented above. + +``CMAKE_EXPERIMENTAL_CXX_MODULE_DYNDEP`` + Set this to ``1`` in order to activate this undocumented experimental + infrastructure. This is **intended to make the functionality available + to compiler writers** so they can use it to develop and test their + dependency scanning tool. + +Some compilers already have support for module dependency scanning: + +* MSVC 19.34 and newer (provided with Visual Studio 17.4 and newer) +* LLVM/Clang 16.0 and newer + +For those, only the above variables need to be set by project code. +For compilers with in-development support, additional variables must +be set as follows. + +``CMAKE_EXPERIMENTAL_CXX_SCANDEP_SOURCE`` + Set this to tell CMake how to invoke the C++20 module dependency + scanning tool. + +``CMAKE_EXPERIMENTAL_CXX_MODULE_MAP_FORMAT`` + Set this for compilers that generate module maps. See below. + +``CMAKE_EXPERIMENTAL_CXX_MODULE_MAP_FLAG`` + Set this for compilers that generate module maps. See below. For example, add code like the following to a test project: |