(C++) How to cross-compile a Qt Creator project from Ubuntu to a windows executable: example 15: MXE

This is a successful approach to solve the Qt FAQ How to cross-compile a Qt Creator project from Ubuntu to a windows executable?, following [1].

See MXE for more information about MXE.

Downloads

Download the Qt Creator project 'CppQtCrosscompileToWindowsExample15' (zip)
Download the Windows executable created by the Qt Creator project 'CppQtCrosscompileToWindowsExample15' (zip)

Technical facts

Application type(s)

Desktop application

Operating system(s) or programming environment(s)

Ubuntu 10.10 (maverick)
Windows XP

IDE(s):

command line
Qt Creator 2.0.1

Project type:

Console application

C++ standard:

C++98

Compiler(s):

G++ 4.4.5

Libraries used:

Boost: version 1.42
STL: GNU ISO C++ Library, version 4.4.5

Qt project file: CppQtCrosscompileToWindowsExample15.pro


#-------------------------------------------------

#

# Project created by QtCreator 2010-09-25T09:43:28

#

#-------------------------------------------------

QT       += core

QT       -= gui

LIBS += -lboost_filesystem-mt -lboost_system-mt

TARGET = CppQtCrosscompileToWindowsExample15

CONFIG   += console

CONFIG   -= app_bundle

TEMPLATE = app

SOURCES += main.cpp

main.cpp


#include <iostream>

#include <string>

#include <vector>

//---------------------------------------------------------------------------

#include <boost/filesystem.hpp>

//---------------------------------------------------------------------------

//From http://www.richelbilderbeek.nl/CppGetFilesInFolder.htm

const std::vector<std::string> GetFilesInFolder(const std::string& folder)

{

  std::vector<std::string> v;



  const boost::filesystem::path my_folder

    = boost::filesystem::system_complete(

        boost::filesystem::path(folder));



  if (!boost::filesystem::is_directory(my_folder)) return v;



  const boost::filesystem::directory_iterator j;

  for ( boost::filesystem::directory_iterator i(my_folder);

        i != j;

        ++i)

  {

    if ( boost::filesystem::is_regular_file( i->status() ) )

    {

      const std::string filename = i->path().filename();

      v.push_back(filename);

    }

  }

  return v;

}

//---------------------------------------------------------------------------

//From http://www.richelbilderbeek.nl/CppGetPath.htm

const std::string GetPath(const std::string& filename)

{

  return boost::filesystem::path(filename).parent_path().string();

}

//---------------------------------------------------------------------------

int main(int, char* argv[])

{

  const std::vector<std::string> v = GetFilesInFolder(GetPath(argv[0]));

  std::copy(v.begin(),v.end(),std::ostream_iterator<std::string>(std::cout,"\n"));

  std::cout << "Number of files: " << v.size() << '\n';

}

//---------------------------------------------------------------------------

Process

For installation, follow the approach by described by [1].

In the folder with your project


richel@richel1-desktop:~/2Projects/Website/CppQtCrosscompileToWindowsExample15$ i686-pc-mingw32-qmake



richel@richel1-desktop:~/2Projects/Website/CppQtCrosscompileToWindowsExample15$ make



make -f Makefile.Release

make[1]: Entering directory `/home/richel/qtsdk-2010.04/bin/Projects/Website/CppQtCrosscompileToWindowsExample15'

i686-pc-mingw32-g++ -c -pipe -O2 -frtti -fexceptions -mthreads -Wall -DUNICODE -DQT_LARGEFILE_SUPPORT -DQT_NO_DEBUG -DQT_CORE_LIB -DQT_THREAD_SUPPORT -I'/home/richel/mingw-cross-env-2.15/usr/i686-pc-mingw32/include/QtCore' -I'/home/richel/mingw-cross-env-2.15/usr/i686-pc-mingw32/include' -I'/home/richel/mingw-cross-env-2.15/usr/i686-pc-mingw32/include/ActiveQt' -I'release' -I'/home/richel/mingw-cross-env-2.15/usr/i686-pc-mingw32/mkspecs/unsupported/win32-g++-cross' -o release/main.o main.cpp

i686-pc-mingw32-g++ -enable-stdcall-fixup -Wl,-enable-auto-import -Wl,-enable-runtime-pseudo-reloc -Wl,-s -Wl,-subsystem,console -mthreads -Wl -o release/CppQtCrosscompileToWindowsExample15.exe release/main.o  -L'/home/richel/mingw-cross-env-2.15/usr/i686-pc-mingw32/lib' -lboost_filesystem-mt -lboost_system-mt -lQtCore -lkernel32 -luser32 -lshell32 -luuid -lole32 -ladvapi32 -lws2_32 -lz 

make[1]: Leaving directory `/home/richel/qtsdk-2010.04/bin/Projects/Website/CppQtCrosscompileToWindowsExample15'



richel@richel1-desktop:~/2Projects/Website/CppQtCrosscompileToWindowsExample15$

Now the Windows executable can be found in the /release folder.

External links

MinGW cross compiling environment homepage

Acknowledgements

Thanks to Mark Brand for contacting me: at the first try this approach failed and Mark let me try this approach again.

References

[1] http://mingw-cross-env.nongnu.org/#tutorial


Tutorial

Step 1: Download and Unpack



First, you should ensure that your system meets mingw-cross-env's requirements. You probably need to install some stuff.



When everything is fine, download the latest release:



wget http://download.savannah.nongnu.org/releases/mingw-cross-env/mingw-cross-env-2.15.tar.gz



and unpack the tarball:



tar -xzvf mingw-cross-env-2.15.tar.gz



If you don't mind installing it in your home directory, just skip the following step and go straight to step 3.

Step 2: System-wide Installation (optional)



Now you should save any previous installation of the mingw-cross-env. Assuming you've installed it under /opt/mingw (any other directory will do as well), you should execute the following commands:



su

mv /opt/mingw /opt/mingw.old

exit



Then you need to transfer the entire directory to its definitive location. We will assume again you use /opt/mingw, but feel free to use any other directory if you like.



su

mv mingw-cross-env-2.15 /opt/mingw

exit



We're almost done. Just change to your newly created directory and get going:



cd /opt/mingw



Step 3: Build mingw-cross-env



Enter the directory where you've unpacked the mingw-cross-env. Now it depends on what you actually want ? or need.



If you choose to enter:



make



you're in for a long wait, because it compiles a lot of packages. On the other hand it doesn't require any intervention, so you're free to do whatever you like ? like watch a movie or go for a night on the town. When it's done you'll find that you've installed a very capable Win32 cross compiler onto your system.



If you only need the most basic tools you can also use:



make gcc



and add any additional packages you need later on. You can also supply a host of packages on the command line, e.g.:



make gtk lua libidn



You'll always end up with a consistent cross compiling environment.



After you're done it just needs a little post-installation.

Step 4: Environment Variables



Edit your .bashrc script in order to change $PATH:



export PATH=/where mingw-cross-env is installed/usr/bin:$PATH



Note that any compiler related environment variables (like $CC, $LDFLAGS, etc.) may spoil your compiling pleasure, so be sure to delete or disable those.



Congratulations! You're ready to cross compile anything you like.

Step 5a: Cross compile your Project (Autotools)



If you use the Autotools, all you have to do is:



./configure --host=i686-pc-mingw32

make



Don't worry about a warning like this:



configure: WARNING: If you wanted to set the --build type, don't use --host.

If a cross compiler is detected then cross compile mode will be used.



Everything will be just fine.

Step 5b: Cross compile your Project (Qt)



If you have a Qt application, all you have to do is:



i686-pc-mingw32-qmake

make



If you are using Qt plugins such as database drivers or graphics plugins, you should also have a look at the Qt documentation about static plugins.

Step 5c: Cross compile your Project (Makefile)



If you have a handwritten Makefile, you probably will have to make a few adjustments to it:



CC=$(CROSS)gcc

LD=$(CROSS)ld

AR=$(CROSS)ar



You may have to add a few others, depending on your project.



Then, all you have to do is:



make CROSS=i686-pc-mingw32-



That's it!

Step 5d: Cross compile your Project (OSG)



Using static OpenSceneGraph libraries requires a few changes to your source. The graphics subsystem and all plugins required by your application must be referenced explicitly. Use a code block like the following:



#ifdef OSG_LIBRARY_STATIC

USE_GRAPHICSWINDOW()

USE_OSGPLUGIN(<plugin1>)

USE_OSGPLUGIN(<plugin2>)

...

#endif



Look at examples/osgstaticviewer/osgstaticviewer.cpp in the OpenSceneGraph source distribution for an example. This example can be compiled with the following command:



i686-pc-mingw32-g++ \

    -o osgstaticviewer.exe examples/osgstaticviewer/osgstaticviewer.cpp \

    `i686-pc-mingw32-pkg-config --cflags openscenegraph-osgViewer openscenegraph-osgPlugins` \

    `i686-pc-mingw32-pkg-config --libs openscenegraph-osgViewer openscenegraph-osgPlugins`



The i686-pc-mingw32-pkg-config command from mingw-cross-env will automatically add -DOSG_LIBRARY_STATIC to your compiler flags.

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