CMP0117 | |
------- | |
.. versionadded:: 3.20 | |
MSVC RTTI flag ``/GR`` is not added to | |
:variable:`CMAKE_CXX_FLAGS <CMAKE_<LANG>_FLAGS>` by default. | |
When using MSVC-like compilers in CMake 3.19 and below, the RTTI flag | |
``/GR`` is added to :variable:`CMAKE_CXX_FLAGS <CMAKE_<LANG>_FLAGS>` by | |
default. This behavior is left from support for MSVC versions from Visual | |
Studio 2003 and below that did not enable RTTI by default. It is no longer | |
necessary. Furthermore, it is problematic for projects that want to change | |
to ``/GR-`` programmatically. In particular, it requires string editing of | |
the :variable:`CMAKE_CXX_FLAGS <CMAKE_<LANG>_FLAGS>` variable with knowledge | |
of the CMake builtin default so it can be replaced. | |
CMake 3.20 and above prefer to leave out ``/GR`` from the value of | |
:variable:`CMAKE_CXX_FLAGS <CMAKE_<LANG>_FLAGS>` by default. | |
This policy provides compatibility with projects that have not been updated | |
to expect the lack of the ``/GR`` flag. The policy setting takes effect as | |
of the first :command:`project` or :command:`enable_language` command that | |
initializes :variable:`CMAKE_CXX_FLAGS <CMAKE_<LANG>_FLAGS>`. | |
.. note:: | |
Once the policy has taken effect at the top of a project for a given | |
language, that choice must be used throughout the tree for that language. | |
In projects that have nested projects in subdirectories, be sure to | |
convert everything together. | |
The ``OLD`` behavior for this policy is to place the MSVC ``/GR`` flag in the | |
default :variable:`CMAKE_CXX_FLAGS <CMAKE_<LANG>_FLAGS>` cache entry. The | |
``NEW`` behavior for this policy is to *not* place the MSVC ``/GR`` flag in | |
the default cache entry. | |
This policy was introduced in CMake version 3.20. Use the | |
:command:`cmake_policy` command to set it to ``OLD`` or ``NEW`` explicitly. | |
Unlike many policies, CMake version |release| does *not* warn | |
when this policy is not set and simply uses ``OLD`` behavior. | |
.. include:: DEPRECATED.txt |