| 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``. |
| |
| Policy ``CMP0126`` was introduced in CMake version 3.21. Use the |
| :command:`cmake_policy` command to set it to ``OLD`` or ``NEW`` explicitly |
| within a project. Use the :variable:`CMAKE_POLICY_DEFAULT_CMP0126 |
| <CMAKE_POLICY_DEFAULT_CMP\<NNNN\>>` variable to set the policy for |
| a third-party project in a subdirectory without modifying it. |
| Unlike many policies, CMake version |release| does *not* warn when the policy |
| is not set and simply uses ``OLD`` behavior. See documentation of the |
| :variable:`CMAKE_POLICY_WARNING_CMP0126 <CMAKE_POLICY_WARNING_CMP<NNNN>>` |
| variable to control the warning. |
| |
| .. include:: DEPRECATED.txt |