CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT

.. versionadded:: 3.7.1

CMake sets this variable to a TRUE value when the :variable:CMAKE_INSTALL_PREFIX has just been initialized to its default value, typically on the first run of CMake within a new build tree and the :envvar:CMAKE_INSTALL_PREFIX environment variable is not set on the first run of CMake. This can be used by project code to change the default without overriding a user-provided value:

.. code-block:: cmake

if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT) set_property(CACHE CMAKE_INSTALL_PREFIX PROPERTY VALUE "/my/default") endif()