CMake:How To Build KDE4 Software

A simple example

Let's just start with a simple example for an application, let's name it, well, kFoo. The CMakeLists.txt below gives the project a name, so that the project files for KDevelop/XCode/MSVC will have a good name. It will then find the KDE 4 installation on the system and setup the required include directories. The list of source files will be put into a variable named mySources, which will be automoced and then used to build an executable from it. The executable and its desktop file will finally be installed.

project(kfoo)

find_package(KDE4 REQUIRED)

include_directories( ${KDE4_INCLUDES} )

set(mySources main.cpp mywidget.cpp mypart.cpp)

kde4_automoc( ${mySources} )

kde4_add_executable(kfoo ${mySources})

target_link_libraries(kfoo ${KDE4_KDEUI_LIBS} ${KDE4_KPARTS_LIBS} )

install_targets( /bin kfoo)
install_files( ${XDG_APPS_DIR} FILES kfoo.desktop)

A full-featured example

Ok, and now for a full-featured but non-working example.

Give the project a name, find KDE 4 and setup CMAKE_MODULE_PATH. This has the effect that cmake will also use check the ${CMAKE_SOURCE_DIR}/cmake directory for files if you use include(somefile) or find_package(something). Please note that this directory is added to the former contents of CMAKE_MODULE_PATH. This is important, since if find_package(KDE4) was successfully, it will have setup CMAKE_MODULE_PATH so that it points to the directory where the cmake files installed with kdelibs are located.

project(kfoo)

find_package(KDE4 REQUIRED)

set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake ${CMAKE_MODULE_PATH})

Then apply the required settings:

include_directories( ${KDE4_INCLUDE_DIRS})
add_definitions( ${KDE4_DEFINITIONS} )

Create a variable which holds your source files:

set(kfooSources main.cpp myappl.cpp view.cpp)

If you have Qt designer ui files version 3 or 4 add them to the variable we just created:

kde4_add_ui_files( kfooSources maindialog.ui logindialog.ui)

kde4_add_ui3_files( kfooSources printerdlg.ui previewdlg.ui)

If you have files for the kconfig_compiler add them this way:

kde4_add_kcfg_files( kfooSources settings.kcfg )

You have some DCOP stuff too ? I guess you already almost guessed it:

kde4_add_dcop_skels(kfooSources someinterface.h anotherinterface.h)

kde4_add_dcop_stubs(kfooSources blah.h blub.h)

So, if you have listed everything, you probably want automoc:

kde4_automoc( ${kfooSources} )

Please note that kde4_automoc() doesn't take the name of a variable as argument, but just a list of files. That's why kfooSource is "dereferenced" here.

Finally, tell cmake what you want to build:

kde4_add_executable(kfoo ${kfooSources} )

This is a slightly extended version of the original cmake add_executable(). Additionally it does some more RPATH handling and supports KDE4_ENABLE_FINAL. Just as add_executable() the first argument is the name of the executable followed by the list of source files. If you want to create a library instead of an executable, it works similar:

kde4_add_library(kfoo ${kfooSources} )
set_target_properties( kfoo PROPERTIES VERSION 5.0.0 SOVERSION 5 )

As above with add_executable(), kde4_add_library() is an extended version of the add_library() command. It adds support for KDE4_ENABLE_FINAL and under windows it adds "-DMAKE_KFOO_LIB" to the compile flags. The set_target_properties() command is optional, if you don't need a version number for the library you can just skip it.

KDE is very modular, so if you want to create a KPart, or a control center module, or an ioslave, here's how to do it:

kde4_add_plugin( kfoo ${kfooSources} )

Now your application/library/plugin probably needs to link to some libraries. For this use the standard cmake target_link_libraries() command. For every KDE library there are variables in the form "KDE4_FOO_LIBS" available. Use them and you get also all depending libraries:

target_link_libraries( kfoo ${KDE4_KDEUI_LIBS} ${KDE4_KIO_LIBS})

You can also create a kdeinit-executable if you want to:

kde4_add_kdeinit_executable()