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Diffstat (limited to 'lib/spack/docs/build_systems/cmakepackage.rst')
| -rw-r--r-- | lib/spack/docs/build_systems/cmakepackage.rst | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/lib/spack/docs/build_systems/cmakepackage.rst b/lib/spack/docs/build_systems/cmakepackage.rst index 3c3c96f92c..7ebac48734 100644 --- a/lib/spack/docs/build_systems/cmakepackage.rst +++ b/lib/spack/docs/build_systems/cmakepackage.rst @@ -145,6 +145,20 @@ and without the :meth:`~spack.build_systems.cmake.CMakePackage.define` and return args +Spack supports CMake defines from conditional variants too. Whenever the condition on +the variant is not met, ``define_from_variant()`` will simply return an empty string, +and CMake simply ignores the empty command line argument. For example the following + +.. code-block:: python + + variant('example', default=True, when='@2.0:') + + def cmake_args(self): + return [self.define_from_variant('EXAMPLE', 'example')] + +will generate ``'cmake' '-DEXAMPLE=ON' ...`` when `@2.0: +example` is met, but will +result in ``'cmake' '' ...`` when the spec version is below ``2.0``. + ^^^^^^^^^^ Generators |