How can I add a minimum compiler version requisite?

Question

I want to create a project in C++11 and I use CMake as my build system.

How can I add a minimum compiler version requisite in the CMake config files?

Answer 1

Starting with CMake 2.8.10 the CMAKE__COMPILER_VERSION variables can be accessed by users to get the compiler version. In previous versions those were only reserved for internal purposes and should not be read by user code. They are also not guaranteed to be set for all languages but C and CXX should definitely be available.

CMake also contains operators for version comparison (VERSION_LESS, VERSION_EQUAL, VERSION_GREATER) that you can use to write your version validation code.

Remember that you will need to find out which compiler you have first and then check for the correct version.

Here is a short sample from one of my projects:

if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
    # require at least gcc 4.8
    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.8)
        message(FATAL_ERROR "GCC version must be at least 4.8!")
    endif()
elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
    # require at least clang 3.2
    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.2)
        message(FATAL_ERROR "Clang version must be at least 3.2!")
    endif()
else()
    message(WARNING "You are using an unsupported compiler! Compilation has only been tested with Clang and GCC.")
endif()