Basic kde-builder features

5.2. Basic kde-builder features#

5.2.1. Building Qt#

KDE Builder supports building the Qt toolkit used by KDE software as a convenience to users. This support is handled by a special group named qt6-set. It is defined here.

Note

Qt is developed under a separate repository from KDE software located at https://code.qt.io/cgit/qt/.

In order to build Qt, you should make sure that the qt-install-dir option is set to the directory you'd like to install Qt to, as described in the section called Editing the configuration file.

Now check if you are using default build configs. This is done by this config line:

include ${build-configs-dir}/kde6.yaml: ""

If this is the case, you are on a safe side.

If for some reason you are not using default build configs, then you should ensure that the qt6-set group is added to your kde-builder.yaml before any other projects in the file. Then you should verify that the repository option and branch options are set appropriately.

The repository option if set to "qt6-copy", is to build Qt using a mirror maintained on the KDE source repositories (no other changes are applied, it is simply a clone of the official source). This is highly recommended due to occasional issues with cloning the full Qt module from its official repository.

You can find out available branches here.

Most likely, you would want to exclude qtwebengine from building, as it has significant build requirements. To do this, add it to "ignore-projects" in your config:

global:
  ignore-projects:
    - qtwebengine

Now you can just run the following command:

kde-builder qt6-set

5.2.2. Standard flags added by kde-builder#

To save you time, kde-builder adds some standard paths to your environment for you:

  • The path to the KDE and Qt libraries is added to the LD_LIBRARY_PATH variable automatically. This means that you do not need to edit libpath to include them.

  • The path to the KDE and Qt development support programs are added to the PATH variable automatically. This means that you do not need to edit binpath to include them.

  • The path to the KDE-provided pkg-config is added automatically to PKG_CONFIG_PATH. This means that you do not need to use set-env to add these.

Note that this does not apply if you are using custom toolchain file, for example with cmake-toolchain.

5.2.3. Changing kde-builder's build priority#

Programs can run with different priority levels on Operating Systems, including Linux and BSD. This allows the system to allocate time for the different programs in accordance with how important they are.

kde-builder will normally allocate itself a low priority so that the rest of the programs on your system are unaffected and can run normally. Using this technique, kde-builder will use extra CPU when it is available.

To alter kde-builder so that it uses a higher (or lower) priority level permanently, then you need to adjust the niceness setting in the configuration file. The niceness setting controls how "nice" kde-builder is to other programs. In other words, having a higher niceness gives kde-builder a lower priority. So to give kde-builder a higher priority, reduce the niceness (and vice versa). The niceness can go from 0 (not nice at all, highest priority) to 20 (super nice, lowest priority).

You can also temporarily change the priority for kde-builder by using the --nice command line option. The value to the option is used exactly the same as for niceness.

Note

It is possible for some programs run by the super user to have a negative nice value, with a correspondingly even higher priority for such programs. Setting a negative (or even 0) niceness for kde-builder is not a great idea, as it will not help run time significantly, but will make your computer seem very sluggish should you still need to use it.

To run kde-builder with a niceness of 15 (a lower priority than normal):

kde-builder --nice=15

Or you can edit the configuration file to make the change permanent:

niceness: "15"

Tip

The niceness option only affects the usage of the computer's processor(s). One other major affect on computer performance relates to how much data input or output (I/O) a program uses. In order to control how much I/O a program can use, modern Linux operating systems support a similar tool called ionice. kde-builder supports ionice, (but only to enable or disable it completely) using the use-idle-io-priority option.

5.2.4. Installation as the superuser#

You may wish to have kde-builder run the installation with super user privileges. This may be for the unrecommended system-wide installation. This is also useful when using a recommended single user KDE build, however. This is because some projects install programs that will briefly need elevated permissions when run. They are not able to achieve these permission levels unless they are installed with the elevated permissions.

To take care of this, kde-builder provides the make-install-prefix option. You can use this option to specify a command to use to perform the installation as another user. The recommended way to use this command is with the sudo program, which will run the install command as the super user.

For example, to install all projects using sudo, you could do something like this:

global:
  make-install-prefix: sudo
  # Other options

To use make-install-prefix for only a single project, this would work:

project some-module-name:
  make-install-prefix: sudo

5.2.5. Showing the progress of a project build#

This feature is always available, and is automatically enabled when possible. What this does is display an estimated build progress while building a project. That way you know about how much longer it will take to build a project.