Getting Started/Using an IDE with KDE4

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KDevelop 3 (outdated by KDevelop 4)

This section will explain how to use KDevelop 3.4 to develop KDE 4 applications. If you have any questions, corrections or rants about this section, please post them on the discussion page.


You need at least KDevelop 3.4 for this, which is still a KDE 3 application. Versions lower than 3.4 do not have Qt 4 support among other things. You can get KDevelop at the KDevelop homepage. Make sure you install KDevelop like all other KDE 3 applications, not with your kde-devel user.

You also need the lastest GDB version, which is currently 6.6.0. Note that the GDB version which is shipped with openSuse 10.3 is broken, it constantly crashes when examining variables (which KDevelop does automatically). Use the GDB version from this repository instead.

You need to have the kdelibs API documentation locally, which is described in the build instructions.

You also need ctags, htdig, htmerge and htsearch. valgrind and callgrind can also be useful.

Be sure you followed the steps in the KDE 4 build instructions and have a working KDE 4 environment. Make sure simple KDE 4 applications like Konsole or KWrite can be started from the command line of the kde-devel user without problems.

The following steps are all done with the kde-devel user. You need to login as that user by typing

su - kde-devel

KDevelop has no native support for CMake projects. Fortunately, CMake has the ability to generate KDevelop project files itself. In order to do this, you need to pass the -GKDevelop3 flag to the cmake command. This tells CMake to generate project files for KDevelop alongside the normal makefiles. The best way to do this is to modify your cmakekde function in your .bashrc. Just change

-DCMAKE_BUILD_TYPE=debugfull&& \
make && \
make install;
<syntaxhighlight lang="bash">
cmake $srcFolder -GKDevelop3 -DCMAKE_INSTALL_PREFIX=$KDEDIR \
-DCMAKE_BUILD_TYPE=debugfull&& \
make && \
make install;
After you have done that, re-login so that the changes to the {{path|.bashrc}} file take effect. Then you need to rerun ''cmakekde'' in the (root) build directory of the project you want to work on with KDevelop (if you didn't use ''-GKDevelop3'' on the [[Getting_Started/Build/Environment|building step]]). For example, if you want to work on Konsole, which lives in ''kdebase'', you need to run cmakekde in the {{path|$KDE_BUILD/KDE/kdebase}} directory. This unfortunately completely rebuilds everything, but only once when you change the generator.
Since all environment variables of the kde-devel user are KDE 4 specific, these need to be set back to match your KDE 3 environment before starting KDevelop.
A simple way to do this is to add the following function to your {{path|.bashrc}}:
<syntaxhighlight lang="bash">
function start3app {
  mkdir -p /tmp/$USER-kde
  export PATH=/opt/kde3/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/bin/X11:/usr/games 
  export LD_LIBRARY_PATH= 
  export KDETMP=/tmp/$USER-kde 
  export KDEVARTMP=/var/tmp/$USER-kde 
  export KDEHOME=$HOME/.kde 
  export KDEDIR=/usr 
  export DISPLAY=:0 
  eval "$@"
  source $HOME/.bashrc   #Reset environment variables again
The ''PATH'' and ''LD_LIBRARY_PATH'' variables are taken from the KDE 3 user, and they may be different on your system. Type <syntaxhighlight lang="bash">echo $PATH</code> and <syntaxhighlight lang="bash">echo $LD_LIBRARY_PATH</code> as normal KDE 3 user to get these values. The above function assumes that KDE 3 is installed in the {{path|/usr}} prefix, as it is the case on Debian-based systems. If your KDE 3 is installed to a different prefix, you need to change the line setting ''KDEDIR'' accordingly. Here's an example how you find out your KDE installation prefix; in this example it is /opt/kde3:
<syntaxhighlight lang="bash">
kde-config --prefix
Now you should be able to start KDevelop by typing <tt>start3app kdevelop</tt>. Do that now.
You can start any KDE 3 application with the <tt>start3app</tt> function. Useful candidates include ''Kompare'' and ''kdesvn''.
However, you can not start ''KDbg'' this way to debug KDE 4 applications, since then the environment variables for the debugged application are wrong.
Instead of starting KDevelop by using the ''start3app'' script as ''kde-devel'' user, you can also use the KDE run dialog ''(Alt+F2)'' to start KDevelop:
This starts KDevelop as ''kde-devel'' user but uses the environment variables of the normal user, just like the ''start3app'' script does.
===== TroubleShooting =====
'''Symptome:''' kdevelop says "cannot talk to klauncher". You cannot open a file.
'''Solution:''' add your KDE library path to LD_LIBRARY_PATH, e.g.:
 export LD_LIBRARY_PATH=/opt/kde3/lib
==== Setting up KDevelop ====
Now that KDevelop has started, you need to adjust a few settings. Go to ''Settings->Configure KDevelop...->Documentation'' for this. Remove all entries that are not relevant to KDE 4 coding.
{{note|Although environment variables like $HOME are used in this section, you should replace them with real paths because KDevelop does not resolve environment variables.}}
Optionally, you can add the kdelibs API documentation. You must [[Development/Tools/apidox|create it beforehand]]. Then add the documentation by clicking ''Add...''. In this dialog, use the following settings:
* ''Type'': Doxygen Documentation Collection (needs to be set first)
* ''Location'': {{path|$KDE_SRC/KDE/kdelibs/kdelibs-apidocs/index.html}}
Now add the Qt API documentation, which also must be [[Development/Tools/apidox|created beforehand]], using the following settings:
* ''Type'': Qt Documentation Collection (needs to be set first)
* ''Location'': {{path|$HOME/qt-copy/doc/html/qt.dcf}}
After you have added kdelibs and Qt API documentation, make sure all checkboxes (''TOC'',''Index'' and ''Search'') are enabled. Then, go to the ''Full Text Search'' tab and make sure the paths to the ''htdig'', ''htmerge'' and ''htsearch'' executables are correct. You can then close the settings dialog.
Now it is time to open the project you want to work on by clicking ''Project->Open Project...''. The project files are located in the build directory. For example, if you want to work on Konsole, you need to open {{path|$KDE_BUILD/KDE/kdebase/apps/konsole/konsole.kdevelop}}. You now need to adjust a few project-specific settings in ''Project->Project Options''. You need to do this every time you start to work on a different project.
Sometimes, a KDevelop project file is not present for the folder you want to work on.
This can have several reasons, it depends on how the CMake files are written. Usually, CMake files which have a <tt>project(projectname)</tt> statement in them should work fine. Once you are familiar enough with CMake, you can try adding the statement.
A workaround for this is to simply use the KDevelop project file of the parent folder, or even higher. In this case, you need to use the <tt>Make Active Directory</tt> entry in the context menu of the <tt>File Selector</tt> sidetab. With this, you can ignore the other unwanted folders when building and installing.
* ''C++ Support->Code Completion''
:Here you need to add code completion databases for Qt and kdelibs, and more if you like, for example you might need a database for ''kdepimlibs'' when working on ''kdepim''.
:For kdelibs, click the ''Add...'' button and choose ''KDevelop Custom Directory PCS Importer'', then add your KDE include directory ({{path|$HOME/kde/include}}) to the list and proceed. You can use the file selection dialog and the ''Add'' button to add it. 
:Now, add the database for Qt 4 by selecting ''KDevelop Qt4 PCS Importer'' this time. You need to select the Qt 4 include directory, which is {{path|$HOME/qt-copy/include}}.
{{note|The Qt4 PCS Importer is only needed if you didn't install Qt4, i.e. you use it directly from the build directory. The drawback of using the Qt4 importer is that it doesn't show progress and the application seems to hang while it imports. The alternative is to use the Custom Directory PCS Importer for this too}}
* ''C++ Support->Qt Options''
:Check ''Enable Qt options'' and choose Qt4 as your version. Set the ''QMake Binary'' path to {{path|$HOME/qt-copy/bin/qmake}}. Then choose ''Qt 4 style'' as ''Qt include syntax''. Use {{path|$HOME/qt-copy/bin/designer}} as ''Designer Binary''. Make sure to use the ''Change Plugin Paths'' dialog to add the plugin directory from KDE so you see the KDE widgets when designer is started. To do this add {{path|$HOME/kde/lib/kde4/plugins}} to the lineedit and then click the ''Add'' button.
* ''Run Options''
:Make sure you use the correct binary as ''Executable''. For example, if you want to run Konsole, this is {{path|$KDE_BUILD/KDE/kdebase/apps/konsole/src/konsole}}. You should add ''--nofork'' to the ''Debug Arguments'' or debugging some applications like ''KMail'' will not work at all.
:Because the ''start3app'' functions changes some environment variables, you need to change them back here so the KDE 4 applications can be run without problems from within KDevelop.
:For some applications, like Konsole, this is not strictly necessary, but others like KMail will crash if you do not change this.
:Simply click the ''Add / Copy'' button to add new environment variables. You will need the following, which are the same as in your [[Getting_Started/Increased_Productivity_in_KDE4_with_Scripts/.bashrc|{{path|.bashrc}}]]:
:{| border="1"
! Name
! Value
| $HOME/.kde4
| $KDEDIR/bin:$QTDIR/bin:/usr/local/bin:$PATH
| /tmp/$USER-kde4
| /var/tmp/$USER-kde4
| $HOME/kde
| 42
* ''Build Options->Build''
:Make sure the correct build directory is selected. Again, for Konsole, this would be {{path|$KDE_BUILD/KDE/kdebase/apps/konsole}}.
* ''Build Options->Make''
:You might want to check ''Abort on first error''. You also might want to add ''VERBOSE='' or ''VERBOSE=1'' to ''Additional make options'' to control the level of verbosity for the build process.
:If you have more than one processor or if you have access to an icecream cluster, you might want to check the ''Run multiple jobs'' option and set the ''Number of simultaneous jobs'' to the number of available processors. This increases the compile speed. It is the same as the <tt>-j</tt> option for ''make''.
* ''Formatting''
:You should set all options here to match the coding style of the project you are working on.
* ''CTags->General''
:You need to correctly set the ''Path to ctags binary'', which is {{path|/usr/bin/ctags}} on Debian-based systems. 
:You probably want to enable the <tt>When more than one hit, go directly to the first</tt> option.
Now you have finished adjusting your project-specific settings. Now you should remove some plugins you do not need, in ''Settings->Configure Plugins...''. I for example disable the following plugins: 
<small>Abbreviation Expansion, Code Snippets, Doxygen Support, Embedded Konsole, File Tree, '''Final Packaging Support''', "Open with" Menu Addon, QuickOpen, Regular Expression Tester, Scripting, '''Security Checker''', Shell Filtering and Insertion, Text Structure and Tools Menu Addition.</small>
You should at least disable the bold ones.
Now, open any source file if none is open already. This will enable the ''Settings->Configure Editor...'' entry, where you need to set the tab options to match the tab style used by the project you are working on. The important settings are:
* ''Appearance->Borders->Show line numbers'': Should be checked.
* ''Appearance->Borders->Show icon border'': Should be checked.
* ''Editing->Tabulators'' 
* ''Editing->Static Word Wrap->Show marker'': Should be checked
* ''Indentation->Automatic Indentation->Indentation mode'': Should be ''C Style''
* ''Indentation'' in general
In the mainwindow, click the ''CTags'' tab on the bottom tabbar, then click the ''Regenerate'' button to create a CTags database for easier source code navigation.
Now you have completed all essential configuration, congratulations!
==== Using KDevelop ====
Refer to the [ KDevelop manual] for general help using KDevelop. The following section will only deal with special cases for KDE 4.
===== Debugging =====
KDE apps have many symbols, which means that you need a lot of memory to get a decent loading times for debugging. To quote a GDB developer: "I would be reluctant to debug KDE on something with <1GB RAM."
If the stepping function of the debugger is slow for you, try the following tips:
* Hide local variables. The <tt>Locals</tt> part of the variable tab on the left causes a big slowdown when stepping if you have many local variables. Simple collapse the <tt>Locals</tt> part of the tree, the local variables are then not updated every step. You can still examine variables by using the <tt>Evaluate expression</tt> function.
* Use the patch at It prevents the update of the framestack widget at each step, speeding up stepping considerably. The patch introduces some minor glitches, which is why it is not yet commited.
KDevelop does not yet support modifing the CMake build system. This means you can not use KDevelop to add or remove files from the project or to change any other aspect of your project's build process.
You need to modify the CMake files by hand and then rerun <tt>cmakekde</tt> instead. Read the [[Development/Tutorials/CMake|CMake tutorial]] to learn how to do this.
{{tip|When you work on libraries, you first need to install them before you can test or debug your changes. 
Since this is cumbersome and time consuming, you should create symlinks ''(ln -s)'' pointing from the build directory to the installation directory for all affected libraries. 
Often, even simple programs use libraries internally, for example the settings dialog of Konsole is really a library.}}
=== Eclipse ===
    |[[image:Snapshot-eclipse.png|right|thumb|200px|KDE4's ktimetracker loaded as eclipse project]]
This describes how to use Eclipse to develop KDE 4 applications. It has been tested with Eclipse Ganymed and SUSE Linux 11.1 but should work same or similar with every combination. As an example KDE application we use [ ktimetracker] from the kdepim module, other applications short work analog.
Using this description you will be able to
* update your working copy of KDE source code using the command svn
* build your KDE module using cmake
* build your KDE application from within eclipse using make
* compile and run your application with one click from eclipse
* get auto-completion when editing KDE source code
* have an overview and navigation about your classes within eclipse
* have call trees for your functions
==== Set up Eclipse with KDE  ====
* Check your requirements
: Trying with a virtual machine [[User:Tstaerk|I]] had problems starting Eclipse with less than 1 GB RAM. After assigning 3 GB RAM to my virtual machine, Eclipse finally started. 
* Install eclipse
: Download Eclipse IDE for C/C++ developers from We unpack it to /home/user/eclipse. 
* Install the CDT
: Download the Eclipse IDE for C/C++ Developers (68 MB) from and unpack it into your eclipse folder, in our case /home/user/eclipse. 
* Download kdepim
: As said, we use kdepim as example here. So, download ("checkout") kdepim using svn, e.g. as anonymous: 
 svn co svn://
: We assume you checked out into /home/user/kdepim. 
* Compile kdepim
: Compile kdepim so the usual makefiles are present for all kdepim applications. If you have problems doing this, follow our [[Getting Started/Build|build instructions]] 
* Import your project into eclipse
: Surprise: To import your project, you should not use "File -&gt; Import". Rather do: File -> New -> C++ Project -> Makefile project -> Empty Project -> un-tag "use default location" -> choose /home/user/kdepim/ktimetracker. Call it "ktimetracker".
* Build your project
: Make sure Project -> Properties -> C/C++ Build -> Builder Settings -> Build location -> Build directory is set correctly.
: Choose Project -> Build Project
* Run the project
: Choose Project -> Properties -> Run/Debug Settings -> New. As project, enter ''ktimetracker'', as C/C++ Application, enter /home/user/kdepim/ktimetracker/ktimetracker. Choose Apply -> Ok -> Ok. Now you can click on the "Run" button and start it.
==== Know-How ====
===== Custom builders =====
If you want to integrate the cmake build step into your build toolchain, you will need to 
* create a custom ''builder'' like this:
 cat >/bin/eclipsebuild<<EOF
 cmake . && make -j4 && make install
 chmod 777 /bin/eclipsebuild
* Add your builder
: Choose Project -> Properties -> Builders. Un-tag all existing builders. Click "new" -> Program -> (name it "Builder for KDE"). -> Location: /bin/eclipsebuild -> Working directory /home/user/workspace/myproject1/kdepim.
* Build
: Now you can build your project. Every time after you restarted eclipse, choose myproject1 -> Project -> Properties -> C/C++ Build -> Ok -> Project -> Build.
===== Revert what eclipse did =====
To revert what eclipse did to your project simply run
 rm -rf .externalToolBuilders/ .project .cproject
===== Why Subversion does not work =====
When using eclipse's svn plugin and building a KDE program, you will get error messages complaining that your svn binary is too old. If you want to try and change this, here's how you get to that error:
* Install the subversion plug-ins
: Help -> Software Updates -> Available Software -> Add Site -> -> Add Site ->
: Now add it: Subversive Site -> Subversive SVN Team Provider Plugin 
: Subversive SVN Connectors Site -> Subversive SVN Connectors -> SVNKit 1.3.0 Implementation (Optional) 
* Click on Install
* Restart eclipse
* Import your KDE module
: Choose File -> New -> Other -> SVN -> Project from SVN -> -> Check out as project configured using the New Project Wizard -> C++ Project -> Makefile Project -> Empty Project. As name, we choose kdepim5 -> Finish
* Set cmake as build environment
: Choose Project -> Properties -> C/C++ Build -> Builder Settings. Un-tag "use default build command", set "cmake" instead. Choose Project -> Properties -> C/C++ Build -> Behavior. Replace "all" by ".".
==== See also ====
=== QtCreator ===
This describes how to use QtCreator to develop KDE 4 applications. It has been tested with QtCreator 1.2.80 and SUSE Linux 11.1 but should work same or similar with every combination. As an example KDE application we use [ ktimetracker] from the kdepim module, other applications should work same or similar.
==== Load an existing project ====
As discussed here we use ktimetracker as example project.
* Import the CMakeLists.txt file
File -> Open -> kdepim/CMakeLists.txt.
* Configure qtcreator to build only ktimetracker
Projects -> ktimetracker -> build settings -> Add a configuration ktimetracker.
As build directory choose kdepim. As arguments for cmake use e.g.
==== Start a KDE project ==== 
To start a new project you need to tell qtcreator to use the KDE libraries when building. So, choose File -> New... and create your project. We will call it ''yourproject'' here. To be able to use KDE's libraries, go to your home directory, cd into ''yourproject'' and modify ''''. Add a line
 LIBS += -lkdeui

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