CMake: How to implement version check in a config file? - cmake

Question

I Customize CMake package configure file OpenCLConfig.cmake for opencl-icd.
refer to Create CMake XXConfig.cmake let other cmake project invoke
Now, I encounter a problem: How to implement version check in a config file.
I create OpenCLConfigVersion.cmake beside OpenCLConfig.cmake, which content is:
#OpenCLConfigVersion.cmake
set(OpenCL_VERSION 2.2)
set(OpenCL_VERSION_MAJOR 2)
set(OpenCL_VERSION_MINOR 2)
SET(OpenCV_VERSION_PATCH 0)
SET(OpenCV_VERSION_TWEAK 0)
While I invoke it opencl-icd in others CMakeLists.txt,
that is find_package(OpenCL config)
I got this error:
CMake Error at CMakeLists.txt:10 (find_package): Could not find a
configuration file for package "OpenCL" that is compatible with requested
version "2". The following configuration files were considered but not
accepted: C:/SDKs/ocl-icd/OpenCLConfig.cmake, version: unknown
I have set OpenCL_DIR as "C:/SDKs/ocl-icd" in my CMakeLists.txt.
My customized OpenCLConfig.cmake which content is
set(OpenCL_FOUND TRUE)
set(OpenCL_ROOT_DIR "C:/SDKs/ocl-icd")
set(OpenCL_VERSION 2.2)
set(OpenCL_VERSION_MAJOR 2)
set(OpenCL_VERSION_MINOR 2)
SET(OpenCV_VERSION_PATCH 0)
SET(OpenCV_VERSION_TWEAK 0)
find_path(OpenCL_INCLUDE_DIR NAMES CL/cl.h PATHS "${OpenCL_ROOT_DIR}/include")
set(OpenCL_INCLUDE_DIRS "${OpenCL_INCLUDE_DIR}")
find_library(OpenCL_LIBRARY NAMES OpenCL.lib PATHS "${OpenCL_ROOT_DIR}/lib")
set(OpenCL_LIBRARIES ${OpenCL_LIBRARY})
How do I handle version problem.

Answer 1

I have solved.
I refer to OpenCVConfig-version.cmake write my OpenCLConfigVersion.cmake
#OpenCLConfigVersion.cmake
set(OpenCL_VERSION 2.2)
set(PACKAGE_VERSION ${OpenCL_VERSION})
set(PACKAGE_VERSION_EXACT False)
set(PACKAGE_VERSION_COMPATIBLE False)
if(PACKAGE_FIND_VERSION VERSION_EQUAL PACKAGE_VERSION)
set(PACKAGE_VERSION_EXACT True)
set(PACKAGE_VERSION_COMPATIBLE True)
endif()
if(PACKAGE_FIND_VERSION_MAJOR EQUAL 2
AND PACKAGE_FIND_VERSION VERSION_LESS PACKAGE_VERSION)
set(PACKAGE_VERSION_COMPATIBLE True)
endif()
It work normally after modify.