CMake User-specified Options

I want to make CMake configuration for a project that depends on OGRE. Obviously, the user needs to specify the directory where OGRE is installed. Is it possible to specify such an option in CMake? I want to be able to write something like:

include_directories(${OGRE_HOME})

Where the variable OGRE_HOME is to be specified by the user.

Still better, is it possible to make CMake automatically looks for OGRE, or any other librar开发者_运维技巧y?!

Thanks!

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Your best bet is to search for a FindOgre.cmake, which can do this for you. Ogre already provides one in $Ogre_DIR\CMake.

You can copy this one to your project (or use CMAKE_MODULE_PATH to specify an additional location with findXXX.cmake files). You can then use find_package( Ogre ) in your cmakelists.txt to search for Ogre and your user needs to specify an environment variable OGRE_HOME or a Cmake-variable OGRE_HOME.

In general: If you rely on 3rd-party libraries, you should have findXXX.cmake files, which can be called by CMake's find_package command. For many common 3rdparty libs, these files are already provided by cmake.