Compile on MinGW

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(2019) The contents of this page are obsolete. Please help us to keep it updated!
Meanwhile, try other compilation options.

How to build and run FreeCAD under MSYS/MinGW


Here comes a short introduction how to setup a MSYS/MinGW environment on a Windows system, to build all needed libraries and finally to build the FreeCAD sources.


If not already installed get a MinGW installer from the Sourceforge page at When writing this tutorial the latest version was mingw-get-inst-20100831.exe. Download and just double-click the excutable. This installs the compiler and a minimal Windows developer environment. Make sure to also install the Fortran compiler because there is a single Fortran file in the 3rd party folder of the FreeCAD sources.

Then as second step MSYS needs to be installed to have an environment to run ./configure scripts which we make heavy use of in order to build all needed libraries. From the Soureforge page the file MSYS-1.0.11.exe was taken.

A virginal MSYS/MinGW installation lacks of a few modules we later need. First, we need the utility pexport which can be found in the file pexports-0.44-1-mingw32-bin.tar.lzma. I don't know where to put this file and how to make MSYS to install the stuff inside. But the file can be opened with a ZIP program and the content can be copied to their destination manually. Here, the pexports utility can go to the bin directory of your MinGW installation.

Then, we also need the development files for the pthreads module which is part of the file pthreads-w32-2.8.0-3-mingw32-dev.tar.lzma. Just download and copy the files inside to your MinGW installation.


Download the CMake utility from Get the archive with the binaries for the Windows platform and unpack whereever you want. There is nothing further to do for this.


Download the SWIG utility from and extract it somewhere on your harddisk.

Third party libraries

Here is a description which libraries we need for FreeCAD and how to build them from the sources. In order not to pollute our MinGW installation with too many files from the 3rd party libraries we have to build you can e.g. create a sub-directory "local" in your MSYS installation. If you have installed MSYS under C:\MSYS then simply create the directory C:\MSYS\1.0\local.


For zlib there is already a ready package for MinGW. So, therefore simply download the file libz-1.2.3-1-mingw32-dev.tar.gz from the Sourceforge site and extract the two directories lib and include to C:\MSYS\1.0\local.


It seems to be nearly impossible to build the Python sources directly with the MinGW compiler. This is because some Python modules require some features which are not implemented on the MinGW platform. Fortunately, the Python sources are plain C code and instead of trying to build it with MinGW you can get a ready binary package built with the MSVC compiler. You can install the Python stuff whereever you want. Afterwards copy the include folder to C:\MSYS\1.0\local, the DLL can go to C:\MSYS\1.0\local\bin.

Now we also need the so called import library. There we cannot use the .lib file which comes together with the installer. But it's easy to create one with the pexports/dlltool utilities. Assuming the Python version is 2.6 do these two steps:

 pexports python26.dll > python26.def
 dlltool -D python26.dll -d python26.def -l libpython26.dll.a

The file libpython26.dll.a can now be moved to C:\MSYS\1.0\local\lib.


For this library we don't need any header files but only the import library to build the Salome SMESH sources. The easiest way to build this file is:

 pexports libgfortran-3.dll > f2c.def
 dlltool -D libgfortran-3.dll -d f2c.def -l libf2c.dll.a

The file libf2c.dll.a can now be moved to C:\MSYS\1.0\local\lib.


Download a source archive from and extract it. Open a MSYS command line window and change to the xerces-c sources. From there run

./configure LDFLAGS=-no-undefined 

Once ./configure has finished it's best to move to the source directory because we don't need to build the dozens of test applications and other stuff. So, do this:

 cd src
 make install

This takes a few minutes to be done.


For boost there exists a testing package with cmake support. This, however, seems to be stable enough to build with the MinGW compiler. So, get the file from and unpack it.

Now, start the cmake-gui.exe from within the MSYS command line. This is necessary for cmake in order to find the compiler and other stuff. Select the folder of the boost sources with the CMakeLists.txt file, select a build directory and start Configure. You'll be asked for which system you want to generate the Makefiles. Select MSYS/Makefiles, not MinGW/Makefiles.

When the configuration step has finished go to the options and search for WINMANGLE_LIBNAMES. Switch this off because otherwise the boost library names contain the compiler name. This causes the boost cmake check to fail later when we try to build the FreeCAD sources. And for the installtion folder choose the directory C:\MSYS\1.0\local.

So, reconfigure boost and press on Generate once it has finished. Close the CMake GUI window and enter

 make install

into the command line. This will take a couple of minutes.


Download eigen-2.0.15.tar.gz or any later version from Unpack the files and start again cmake-gui. Set the installation directory to C:\MSYS\1.0\local and press on Configure and Generate. Close the window and start the installation with

 make install

o Qt4 From the Qt website at you can download already prebuilt packages for the MinGW platform. But depending on the version you have installed it can happen that they don't fit together. In this case the source tarball must be downloaded. Use version 4.5.3 or higher. Unpack the sources and start the configure.exe you'll find inside the sources.


By default the build the debug and release version. If you only want the release version use the option "-release".

Configure will ask you some questions under which license you want to use Qt. Choose LGPL here. Now run the build with


This can take quite some time because Qt has become a really huge library over the years. Once the build has finished run a

 make install

to copy the header files to their right place. All the binaries and header files are still inside the source folder. If you like you can copy all the .dll, .a, and the direcories under "include" to the subdirectories of C:\MSYS\1.0\local.


Get a source archive from Unpack the sources and run

 make install

It may happen that a message dialog pops up due to a missing cygwin1.dll. You simply ignore this.


Get a source archive from Unpack the sources and run

 ./configure CXXFLAGS="-DCOIN_DLL" --with-qt=/usr/local
 make install

In case your Qt development files are not under /usr/local choose the correct directory there. Again a message dialog may pop up due to the missing cygwin1.dll.


Warning: the following is obsoleted from version 0.14, since FreeCAD is now using pySide instead of PyQt. At the moment, PySide suport for MingW seems still not complete:

Download the sources archives for sip and PyQt4 from

In order to build sip extract the archive and open a MSYS command line. From within its source archive call

 python --platform win32-g++ --destdir=/usr/local

It may happen that this step aborts because the Python include headers cannot be found. In this case edit the Makefile and add the include path for the ython headers and also the path and filename of the Python library.

Unfortunately, the 'make install' command doesn't work because the Makefile was generated to use Windows batch commands instead of bash commands. Thus, copy the following files to a path where Python can find it, e.g. /usr/local/bin.

In order to build PyQt4 extract the source archive and open a MSYS command line. Go to the directory and start

 export PATH=/usr/local/lib/:$PATH
 python --destdir=/usr/local/lib/site-packages

Since the Makefile doesn't find the Python header files copy them all and also the file sip.h to a directory where they can be found. A good place seems to be the directory of the Qt sources. There copy the files to $QTDIR/include. The Python library file python26.dll.a can go $QTDIR/lib.

After the build has finished you have to copy all files that end with .pyd to their destination, e.g. /usr/local/lib/site-packages/PyQt4. Lateron when you have built the FreeCAD sources you have to copy the PyQt4 directory and sip.pyd to the FreeCAD bin directory or set a symlink.


TODO: Still not clear if this will be used. (, >= 0.10.x


For the build of the OpenCASCADE libraries get the sources from or alternatively it is also possible to download a stripped source tarball from the Debian mirrors which don't include any fonts and other resource files.

Unpack the sources and download a CMake script from and the file occ_config.h.cmake. Copy both files into the 'ros' directory, start cmake-gui from within a MSYS command line and select MSYS Makefiles. In the options the following switches can be disabled:


Then specify for OPENCASCADE_INSTALL_PREFIX C:/MSYS/1.0/local as destination directory-

Now click the Configure button which takes a while and afterwards the Generate button.

Note 1

The original sources don't completely compile with MinGW. Therefore you have to apply the patch OpenCASCADE6.3.0-MinGW.patch from

Note 2

The original sources includes also a configure script and the files. But it appeared to be very hard to build the libraries this way. Thus, it highly recommended to do it the CMake way.

Note 3

For a couple of libraries the arguments passed to the linker exceeds the number of allowed characters and thus the linker stops with an error: "Bad file number". To solve this issue you can open the file build.make of the according library and split the block (e.g. TKGeomAlgo_OBJECTS) into several smaller ones and modify the build rule this way that you create first a static library, add the other object files to the group and then unpack the static archive into one directory. This trick solves the problem to reduce the whole number of characters. Afterwards the shared library can be built out of these object files.

Example: If the build.make file has a line of the form

   g++ <options> -shared -o libTKGeomAlgo.dll $(TKGeomAlgo_OBJECTS) <libs>

then change it into

   ar rcs win32/libTKGeomAlgo.a $(TKGeomAlgo_OBJECTS1)
   ar q win32/libTKGeomAlgo.a $(TKGeomAlgo_OBJECTS2)
   ar x win32/libTKGeomAlgo.a
   g++ <options> -shared -o libTKGeomAlgo.dll *.obj  <libs>
   rm -f *.obj


Modify the following files:

  • libsrc/meshing/improve2.hpp
 Add  DLL_HEADER to class MeshOptimize2d
  • libsrc/meshing/meshclass.hpp
 Add  DLL_HEADER to CalcSurfacesOfNode
  • libsrc/meshing/meshtype.hpp
 Add  DLL_HEADER to classes SurfaceElementIndex, MeshPoint, Element2d (int anp), 
  • libsrc/occ/occgeom.hpp
 Add  DLL_HEADER to classes Line, OCCGeometry, OCCParameters, OCCGenerateMesh
  • libsrc/occ/occmeshsurf.hpp
 Add  DLL_HEADER to classes OCCSurface, Meshing2OCCSurfaces, MeshOptimize2dOCCSurfaces, OCCRefinementSurfaces

Run the configure script with these arguments

 ./configure --prefix=/usr/local --enable-shared --enable-occ --with-occ=/usr/local --with-tcl=/usr/local/lib --enable-nglib CXXFLAGS="-DNGLIB_EXPORTS -DWNT"
 make && make install

Building the FreeCAD sources

In order build the FreeCAD sources either get the developer sources from the SVN repository or get one of the .tar.gz tarballs and extract it. Now start cmake-gui.exe from within a MSYS command line window and browse to the FreeCAD sources and also define the build directory. Now run Configure. It may happen that cmake complains about some not found libraries. In this case go through the listed libraries and choose the include directory and/or the path to the library where needed. Once Confgiure accepts all your input create the Makefiles by clicking on Generate. Now close the window and enter

 make install

This will take a couple of minutes. From the command line window change to the FreeCAD bin folder and start the application with ./FreeCAD. In case it complains about some DLLs it cannot find you have to extend your PATH environment variable with

 export PATH=$PATH:/usr/local/bin:/usr/local/lib

If no grave problems remains repeating ./FreeCAD should start the application now.


In order to let CMake detect the boost libraries you must make sure that the DLLs are in the system path because the check builds some test applications and tries to start them. If the DLLs are not in path CMake says that it cannot find boost. In this case do a export PATH=/usr/local/lib:$PATH

Have fun!