How can I use CMake to build wxwidgets on demand and link to it

I see three different ways to do this:

Method 1: use find_package

Use wxWidgets as a separate requirement for your project and expect the developers to install it before building your project. In your CMakeLists.txt you will need to call find_package(wxWidgets)

, for example:

    find_package(wxWidgets COMPONENTS net gl core base)
    if(wxWidgets_FOUND)
        include(${wxWidgets_USE_FILE})
        # and for each of your dependent executable/library targets:
        target_link_libraries(<YourTarget> ${wxWidgets_LIBRARIES})
    endif()

      

        
        
        
      

    

This has the advantage of not rebuilding the lib if you rebuild your project, however, it needs some work for its user (they need to handle wxWidgets manually) and for you (you need to set up include paths / compile definitions / ... manually).

Method 2. Embedding wxWidgets

The second option is to link wxWidgets in your repo (svn external or a git submodule) and usually (re) write the CMakeLists.txt of that library for target orientation. Then, in your topmost CMakeLists.txt, you can do the following:

    # for example, if you just need core and net:
    target_link_librairies(my_app PUBLIC wxWidgetsCore wxWidgetsNet)
    # No need to manually setup include dirs, etc...

      

        
        
        
      

    

To target CMakeLists.txt, you define include directories and other compilation properties for the target, not the directory. Example:

    # When defining wxWidgetsCore, for example
    add_library(wxWidgetsCore ...)
    target_include_directories(wxWidgetsCore PUBLIC someDir)
    target_compile_definitions(wxWidgetsCore PUBLIC -pedantic)
    target_link_libraries(wxWidgetsCore PUBLIC someLib)

      

        
        
        
      

    

The downside to this approach is that restoring your project will restore wxWidgets. It is possible, however, to trick this by not using "rebuild" but "only clean my application and then build". Here's some information on how to achieve this .

Method 3: some kind of hybrid

The big flaw in Method 2 leads to a third approach: don't put wxWidgets in your project, but create a CMakeLists.txt that will "import" the lib. Idea: you ask your user for the directory where wxWidgets is installed, then this script will configure everything for your project. First put CMakeLists.txt here:

    /your-project-root
        /thirdparty
            /wxWidgets
                CMakeLists.txt
    /dir-where-wxwidgets-is-installed
        ...

      

        
        
        
      

    

Now you define the imported target:

    # When defining wxWidgetsCore, for example
    set(WX_INCLUDE_DIR ${USER_SPECIFIED_WX_ROOT}/include)
    add_library(wxWidgetsCore IMPORTED GLOBAL)
    set_property(TARGET wxWidgetsCore APPEND PROPERTY
        INTERFACE_INCLUDE_DIRECTORIES ${WX_INCLUDE_DIR})

      

        
        
        
      

    

See INTERFACE_INCLUDE_DIRECTORIES and INTERFACE_LINK_LIBRARIES . You need your user to build wxWidgets somewhere on his system, but from your point of view, you just do target_link_libraries(your_app PUBLIC wxWidgets...)

like in method 2. The advantage is that this approach is transparent and interchangeable with method 2, and you don't put the whole dependency in your project.