emerge is a tool to build the KDE sources and its third party requirements on MS Windows. It is the easy way to build KDE on MS Windows.

Set up

Create a directory if possible in your harddrive's root e.g. C:\kderoot or D:\kderoot (You will need this PATH later). This directory will contain the whole kde installation later.

emerge.bat invokes an script written in Python, so you first need to install a Python Interpreter.

The latest source code for windows emerge and the rest of KDE is stored in a Subversion repository. You need a subversion client for the first checkout. Command line client is available at

Check out the sources from the svn-directory of emerge into a new directory, which in this example we will call kderoot. If you have command-line tool], you can accomplish this with the following command:

svn co svn://
  • NOTE from a user: On Jan 13, 2008 when I tried this, the above path seemed to NOT work. I neeeded to remove the kdewin32 part in the string
  • Note from another user: I needed to checkout the emerge directory from svn://
  • Note from this same last user: The downloaded (HEAD) emerge was buggy, failing to download anything with wget. I had to replace line 175 of emerge\bin\ with: return utils.getFiles( self.SRC_URI, self.downloaddir ). It looks like the call to kdesettings is path dependant, so I also had to add the following in the kdeenv.bat file (I'm calling etc\kdeenv.bat): call etc\kdesettings.bat
  • Note from new user: I also used svn:// for checking out. Could not download anything with wget. But I have downloaded a couple of files manually and located to /download/ directory. It worked for me!

Alternatively, you can checkout the sources using a program like TortoiseSVN.

Be sure to use a copy of Subversion that was built on Windows so that checked-out files do not use UNIX line endings. If you check out with UNIX line endings, the patch program will fail when attempting to apply a patch whose line endings don't match the system's.

After checkout you need to have directory kderoot\emerge else you can copy your emerge directory to that location.

Create the directory kderoot\etc. Copy the file kderoot\emerge\kdesettings-example.bat to kderoot\etc\kdesettings.bat and change it according to your needs. Then run it.

Be sure that you neither have the msys/bin nor the cygwin/bin in your path. If so you have to definitely remove it.


emerge uses either the MinGW ("Minimalist GNU for Windows") GCC compiler and tools to build Qt and KDE from source code or one of the Microsoft Compilers (> Visual Studio 2003).

Currently, there is no dependency on the compilers in any of the packages. So, unless you call emerge mingw manually, have the compiler installed and in your path or alter the environment configuration scripts to add your existing MinGW bin directory to the PATH variable, compiling anything will choke. If you run emerge mingw, you will not need to modify the environment configuration scripts to point to a custom location.

NOTE from a user: When I tried to do emerge qt, I ended up getting an error about mingw-make not being in the path, thereby forcing me to do an 'emerge mingw' because of that /end note

If you see an error about cc1plus not being found, either add MinGW's \libexec\gcc\mingw32\3.4.5 to your PATH (in command line set PATH=%PATH%;path\to\directory) variable or copy the contents of this directory to MinGW's bin directory. The prior is preferred.

Everything applies to MS Visual Studio Compilers in a similar manner. Note however that for debug builds MS Visual Studio 2005 Service Pack 1 is required due to the use of manifest files and using pre-built packages for some dependecies.

In vista, the mingw directory may need to be moved to c:\ in order to compile properly.

Running emerge

Start a console window and run


Check your path (run: echo %PATH%), it should have python and various directories within kderoot in it.

  • NOTE from a user: be sure that path to \mingw\bin has been set correctly, by default it is pointing to: %KDEROOT%\mingw\bin which does not apply to most installations

You can get 'some' help if you run:

C:\kderoot\emerge\bin>emerge --help

Below the directory kderoot\emerge\portage are subdirectories for categories as subdirectories which contain the instructions for individual packages. The emerge script automatically handles package dependencies (except for the compiler, see #Compiling).

To build every required package for e.g. kdebase enter emerge kdebase. If you want to make a dry run, add the option -p to it.

Start with emerge qt and if that completes successfully, run emerge [TARGET] where [TARGET] has to be replaced with the target you want to build.

What emerge does

emerge will fetch Windows versions of numerous UNIX-like utilities and libraries from the Internet, putting them in kderoot\bin, then get the Win32 support files, then Subversion, then Perl and the Qt libraries, etc.

Then emerge compiles the Qt libraries, this takes hours.

emerge package performs the separate actions --fetch, --unpack, --compile, --install, --manifest, and --qmerge.

emerge commandline options / emerge settings

There are some options that can be used when building with emerge.

-v EMERGE_VERBOSE This option augments the verbosity level - currently the highest verbosity level is 3 (-v -v -v). A verbosity level of 0 should give no output and equals to -q. You can set EMERGE_VERBOSE=3 instead in the environment of the commandline or within your kdesettings.bat file.
--nocopy EMERGE_NOCOPY This very useful option suppresses copying the sources from the local subversion tree to a directory within the build directory. It shouldn't be used while packaging; in the other cases it reduces the amount of harddisk used though and removes the copying time.You can set EMERGE_NOCOPY=True or =False instead.
--offline This option suppresses the update step of the local tree - which needs some time. Be aware though that you have to have existing sources already if you want to use this option.
-t EMERGE_BUILDTESTS This option enables or disables KDE4 buildtests for KDE modules. Other packages will not change. Use EMERGE_BUILDTESTS=True or =False.
--buildtype= Debug This option enables full debugging for the build. Recommended if you plan to debug the runtime or provide more valuable feedback to developers about software defects. You can also change the 'set EMERGE_BUILDTYPE=RelWithDebInfo' line in the kdesettings.bat file.


emerge is mostly usable together with the kdewin-installer but we're currently still working on some packages which are packaged in a wrong way. It is not recommended to use another layout then installer for directory_layout in the kdesettings.bat anymore (see that file for more detailed information).

emerge creates lots of files in \kderoot\tmp during build. After a package is successfully installed (check \kderoot\etc\portage\installed or the directory \kderoot\manifest\), you can delete its temporary directory.

Windows emerge is derived from the Gentoo portage system, but we are currently not enforcing compatibility. If you have questions about that please contact us at the channel #kde-windows on

Vista issues

  • jstaniek 12:02, 15 January 2008 (CET): UAC has infamous heuristics that make programs like patch.exe treat as installers and try to run them with admin rights (!). This heuristics can be tricked by renaming patch.exe to something like pch.exe (example) but we did not want to add item to our infrastructure. Instead it is possibleto turn off the heuristics (see the screenshot here in the security blog calling the heuristics 'severe hole in the design of UAC'). If you happen to disable the UAC, as many annoyed users and devs do (msvc demands admin rights anyway!), patch.exe should already work for you as in older Windows. Alternatively you may want to disable UAC for admins only, but this makes no sense if you are the only user of your machine and use only the admin account.

This page was last edited on 18 March 2016, at 14:58. Content is available under Creative Commons License SA 4.0 unless otherwise noted.