New in version 3.13.

Operator to read cache variables.

Use the syntax $CACHE{VAR} to read cache entry VAR. See the cmake-language(7) variables documentation for more complete documentation of the interaction of normal variables and cache entries.

When evaluating 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 set() and unset() commands to see how to write or remove cache variables.