CMP0126

.. versionadded:: 3.21

When this policy is set to NEW, the :command:set(CACHE) command does not remove any normal variable of the same name from the current scope. The OLD behavior removes any normal variable of the same name from the current scope in the following situations:

No cache variable of that name existed previously.
A cache variable of that name existed previously, but it had no type. This can occur when the variable was set on the command line using a form like cmake -DMYVAR=blah instead of cmake -DMYVAR:STRING=blah.
The FORCE or INTERNAL keywords were used when setting the cache variable.

Note that the NEW behavior has an important difference to the similar NEW behavior of policy :policy:CMP0077. The :command:set(CACHE) command always sets the cache variable if it did not exist previously, regardless of the CMP0126 policy setting. The :command:option command will not set the cache variable if a non-cache variable of the same name already exists and :policy:CMP0077 is set to NEW.

.. |INTRODUCED_IN_CMAKE_VERSION| replace:: 3.21 .. |WARNS_OR_DOES_NOT_WARN| replace:: does not warn by default .. include:: include/STANDARD_ADVICE.rst

See documentation of the :variable:CMAKE_POLICY_WARNING_CMP0126 <CMAKE_POLICY_WARNING_CMP<NNNN>> variable to control the warning.

The :variable:CMAKE_POLICY_DEFAULT_CMP0126 <CMAKE_POLICY_DEFAULT_CMP\<NNNN\>> variable may be used to set the policy for a third-party project in a subdirectory without modifying it.

.. include:: include/DEPRECATED.rst