Guidelines and HOWTOs/Build from source

Build KDE Frameworks and Applications

Design features

Qt and most KDE software are written in C++ whereas its "competitor" GTK is written in C making it very portable and easy to produce language bindings for (for Ruby, Python, Bash etc.). So it is possible to write a complete GTK GUI app in Bash script, but so far that has not been done for Qt.

Safety Precautions

Configuring your build environment is the single most important step in building KDE software. Luckily, KDE Frameworks development libraries are packaged by most major distributions. In general, building and installing user space programs such as Calligra can be done safely without altering any system files. Whenever possible, it is recommended that you build KDE using your normal user account. Unless you are interested in changing the behavior of your system, you should build with a normal account. Even if you are a a KWin or Plasma developer wishing to test a full Plasma session with compositing effects, there are ways to construct the desired testing bed entirely within your normal user account, e.g. running Plasma through a nested X server using xypher.

However, to permanently alter your Plasma desktop environment through new System Configuration Modules and the like, you will often need to install shared libraries and other files in system folders. In these cases, bad installation can render your system unstable or your desktop environment unusable. Always take caution before executing any commands as root! A sudo make install can not always be undone by a simple sudo make uninstall . Technologies like containerization may help solve these problems in the future, but current distribution systems have no way to monitor the alterations you make to system shared libraries as the system administrator. Another option is to use snapshots of a BTRfs formatted system harddisk and use snapper-GUI to roll back in case of an error. Always keep records of what you are doing and make sure you know how to access the install logs to give yourself a better chance of reverting files by hand if necessary. And of course, please keep high quality, frequent backups of your data.

Configuration scripts

A set of configuration scripts and bash commands are provided as a recommended configuration when building KDE software manually. If you use these as provided then your build will be a lot easier and it will be easier for you to find support online. The one disadvantage to these scripts is that they hide important details from you which you may want to learn about. However the scripted and by-hand methods are completely interchangeable so once you are comfortable building KDE using the scripts you can learn more by doing everything yourself.

If you want to do the work by hand you can follow the detailed instructions else continue here on.

Install required devel packages

This section provides information about required and optional software packages needed to build the KDE applications.

Qt5 is the base of KDE software. Your distro provides suitable devel packages containing prominently the Qt C++ header files below /usr/include/****.h . Optionally, you can build your own Qt5.

Follow this page to install the required dependencies.

Git remote prefix

See Get Involved/development#Configure Git

kdesrc-build

See Get Involved/development#Set up kdesrc-build

Testing

Running unit tests

Unit tests are ran from the build dir of each framework; you should first cd into it.

You need a separate DBus session because the dbus server needs to have the right value of XDG_DATA_DIRS, in order to find $KF5/share/dbus-1/services for starting services (e.g. kded5).

 $ eval `dbus-launch`
 $ kdeinit5
 $ make test

Note: Regular apps will start kdeinit5 automatically. The reason it has to be started by hand when running unit tests is some strange interaction with ctest.

Warning: never start a KDE 4 application in this separate DBus session. It would conflict with your running Plasma 4 desktop.

Note: KDE_FULL_SESSION=true is needed to make sure that the correct QPA will be loaded.

Many of the tests require an X server, and will pop up windows briefly. An easy way to allow these tests to run without interfering with your normal X session is to do

 $ xvfb-run -s '-screen 0 1024x768x24' make test

The -s argument tells Xvfb to set the first screen to be 1024x768 pixels, with a depth of 24; at least one test requires a depth greater than 8. In this case, if you also ensure DBUS_SESSION_BUS_ADDRESS is not set, the tests should not find your existing DBus session, and instead launch a new DBus instance.

Note that the KWindowSystem tests require a NETWM-compatible window manager to be running. One way to do this is to create a script to run such a window manager, followed by whatever is passed to it. For example, if you have the window manager awesome installed, you could create a script called awesome-run as follows:

#!/bin/sh
awesome &
exec "$@"

and then run the tests as

$ xvfb-run -s '-screen 0 1024x768x24' /path/to/awesome-run make test

If you want to publish your test results, instead of "make test" run

$ make Experimental

The test results will appear on http://my.cdash.org/index.php?project=<projectname>

Testing Plasma

See Get Involved/development#Plasma

Troubleshooting

Compilation: how to quickly solve build problems

See Get Involved/development#How to solve build problems

Alternative building methods

Docker

The docker container keeps the target KDE separate from the working installation, so no "contamination" with unstable code can occur.

• How to build with Docker