hunter_download

Final stage of adding package to the project. This command will read all package related variables and start the real download/build (or cache unpack) instructions. Name of package and component set by PACKAGE_NAME and PACKAGE_COMPONENT.

Option PACKAGE_INTERNAL_DEPS_ID is an identifier of internal files that build the package (like build scheme or additional scripts). This variable used by cache system to detect the necessity of update the binary cache of package when non of the following changed: package sources, build types, CMake arguments, toolchain-id or dependencies. The rule of thumb is to increase the value of PACKAGE_INTERNAL_DEPS_ID each time you’re applying change of build scheme and making it public (e.g. sending pull request). This should be done for every affected package. If you want to understand the meaning of it better and why such approach used, you can read:

Note

This variable used only by non-CMake packages since CMake-based packages build in a standard way by url_sha1_cmake scheme.