project() command manages VERSION variables.
CMake version 3.0 introduced the
VERSION option of the
command to specify a project version as well as the name. In order to keep
PROJECT_VERSION and related variables consistent with variable
PROJECT_NAME it is necessary to set the VERSION variables
to the empty string when no
VERSION is given to
However, this can change behavior for existing projects that set VERSION
variables themselves since
project() may now clear them.
This policy controls the behavior for compatibility with such projects.
The OLD behavior for this policy is to leave VERSION variables untouched.
The NEW behavior for this policy is to set VERSION as documented by the
This policy was introduced in CMake version 3.0. CMake version 3.7.1 warns when the policy is not set and uses OLD behavior. Use the cmake_policy command to set it to OLD or NEW explicitly.
OLD behavior of a policy is
deprecated by definition
and may be removed in a future version of CMake.