Help/variable/CACHE.rst
.. versionadded:: 3.13
Operator to read cache variables.
Use the syntax $CACHE{VAR} to read cache entry VAR.
See the :ref:cmake-language(7) variables <CMake Language Variables>
documentation for more complete documentation of the interaction of
normal variables and cache entries.
When evaluating :ref:Variable References of the form ${VAR},
CMake first searches for a normal variable with that name, and if not
found CMake will search for a cache entry with that name.
The $CACHE{VAR} syntax can be used to do direct cache lookup and
ignore any existing normal variable.
See the :command:set and :command:unset commands to see how to
write or remove cache variables.