Introduction

This article will try to give some hints for checking out the modularized Qt5 from git and getting it built. Please feel free to update this article as things change during development. Raise issues related to the article on http://developer.qt.nokia.com/forums/viewthread/7018 .

System Requirements

You need obviously git (>= 1.6.x) to get the packages. To properly configure and build Qt 5 from source you also need Perl and Python, as well as a working compiler.

Linux/X11

Build essentials on Ubuntu/Debian:

Libxcb   [xcb.freedesktop.org]  is now the default window-system backend for platforms based on X11/Xorg, and you should therefore install libxcb and its accompanying packages. Qt5 should build with whatever libxcb version is available in your distro’s packages (but you may optionally wish to use v1.8 or higher to have threaded rendering support). src/plugins/platforms/xcb/README   [qt.gitorious.org]  lists the required packages.

Libxcb and friends on Ubuntu/Debian:

Libxcb and friends on Fedora up to 16:

1. su  -  -c  "yum install libxcb libxcb-devel xcb-util xcb-util-devel"

Libxcb and friends on Fedora 17+ (xcb-util-renderutil is currently available in updates-testing repository until it goes stable):

1. su  -  -c  "yum --enablerepo=updates-testing install libxcb libxcb-devel xcb-util xcb-util-devel xcb-util-*-devel"

perl-version on Fedora

1. su  -  -c  "yum install perl-version"

Libxcb on ArchLinux:

1. sudo pacman  -S  --needed libxcb xcb -proto xcb -util xcb -util -image xcb -util -wm

On Chakra Linux, other than packages mentioned for ArchLinux, you need to install package xcb-util-keysyms separately. It’s available from CCR.

Libxcb and friends on Mandriva/ROSA/Unity:

1. urpmi  'pkgconfig(xcb)'  'pkgconfig(xcb-icccm)'  'pkgconfig(xcb-image)'  'pkgconfig(xcb-renderutil)'  'pkgconfig(xcb-keysyms)' 'pkgconfig(xrender)'

For QtQuick2 a graphics driver with native OpenGL 2.0 support is highly recommended.

QtJsonDb depends on libedit:

QtJsonDb dependencies on Ubuntu/Debian:

QtJsonDb dependencies on Mandriva/ROSA/Unity:

When you want to compile webkit, more dependencies need to be satisfied:

Webkit dependencies on Ubuntu/Debian:

Webkit dependencies on Fedora:

1. su  -  -c  "yum install gperf"

Webkit dependencies on Mandriva/ROSA/Unity:

1. urpmi gperf

QtWayland dependencies

To build the QtWayland module, the Wayland [wayland.freedesktop.org] development libraries should be installed ( libxcomposite-dev and libwayland-dev ) .

Mac OS X

XCode and git should be enough.

Windows

Windows Graphics Drivers

For QML2 to work, you need an OpenGL driver (NVidia,etc) that provides OpenGL 2.1 or higher for your graphics card. The Windows default driver provides only OpenGL 1.1, which is not sufficient.

Alternatively, the ANGLE-library [code.google.com] , which provides Open GL ES 2.0 by translating Open GL calls into Direct X, can be used. In order to build it, you need to

1. Install the Direct X SDK [msdn.microsoft.com]
2. Checkout and build ANGLE (SVN repository) as explained here [code.google.com]
3. Note: When building for 64bit, de-activate the WarnAsError option in every project file (as otherwise integer conversion warnings will break the build).
4. When configuring Qt, pass the command line options -opengl es2 -angle <path>

Supported Compilers on Windows

• Windows SDK 7.1 with Visual Studio 2010 (recommended). As of 16.3.2012, installing the SDK requires installing the following packages in this order (see readme.html provided with the service pack):

1. Install Visual Studio 2010
2. Install Windows SDK 7.1
3. Install Visual Studio 2010 SP1
4. Install Visual C++ 2010 SP1 Compiler Update for the Windows SDK 7.1

• Windows SDK 7 with Visual Studio 2008
• MinGW [mingw.org] or TDM MinGW [tdm-gcc.tdragon.net] with g++ version 4.6 or higher (not supported for all modules)

Windows Build environment

We recommend creating a command prompt that provides the build environment (see the Qt Creator README [qt.gitorious.org] ). In this environment, Python (e.g. Active Python 2.7 later) and Perl (e.g. Active State Perl 5.12 or later) should be in the PATH.

Multicore building: When using nmake, the environment variable CL (specifying Visual Studio compiler options) can be set to set CL=/MP, instructing the compiler to use all cores. Alternatively, the tool jom [qt-project.org] can be used. Note however, that it has issues with module interdependencies, which can cause builds to fail.

Hint: Make sure that Perl is added to the path in front of git since that ships an outdated version (Perl 5.8), which will cause the scripts to fail.

ICU on Windows

Qt 5 can make use of the ICU [site.icu-project.org] library for UNICODE and Globalization support. This is required for building QtWebKit.

At compile time, the include and lib folders of the ICU installation must be appended to INCLUDE and LIB environment variables after calling the setup script of the Windows SDK.

At run-time, the ICU DLLs need to be found. This can be achieved by copying the DLLs to the application folder or adding the bin folder of the ICUinstallation to the PATH environment variable.

Getting the source code

First clone the top-level Qt 5 git repository:

or (if you’re behind a firewall and want to use the https protocol):

Following the README [qt.gitorious.org] – file we initialize the repository using the script init-repository which clones the various sub-modules of Qt5. Relevant options:

• —no-webkit : Consider skipping qtwebkit by passing this option. This module is quite big, takes a long time to compile and if often a source of compile errors, so it is recommend to only download it if you intend to use it. You can always re-run init-repository later on to add it.
• —http : Pass this option if you’re behind a firewall.

If you plan to contribute to Qt, you should specify your codereview username so that the git remotes are properly set up:

Configuring and building

Setup your path so that we pick up the Qt5 tools rather than any old Qt4 ones that may be present on your system:

For Linux/Mac OS X:

For Windows:

Now configure the build (from top level dir). Disabling tests and examples will greatly speed up compilation:

For Linux/Mac OS X:

For Windows:

The -developer-build options export more symbols than in a traditional Qt build in order to allow more classes and functions to be unit tested. It also defaults to a ‘debug’ build, and installs the binaries in the current directory, avoiding the need for ‘make install’. ‘-opensource’ sets the license to be LGPL 2.1. The -nomake examples and -nomake tests parameters make sure examples and tests aren’t compiled by default. You can always decide to compile them later by hand.

• Hint1: On Linux you should also pass -no-gtkstyle. This is because on a number of systems (at least SUSE and Gentoo) pkg-config —cflags gtk+-2.0 actually returns paths that include the system Qt4.x include directories.

• Hint2: You can add -confirm-license to get rid of the question whether you agree to the license.

• Hint3: On Windows, you might not be able to build if sh.exe is in your PATH (for example due to a git or msys installation). Such an error is indicated by qt5-srcqtbasebinqmake.exe: command not found and alike. In this case, make sure that sh.exe is not in your path. You will have to re-configure if your installation is already configured.

Building happens by invoking the build perl script:

For Linux:

For Windows (MSVC):

Or just make a specific module, e.g. declarative, and modules it depends on:

*Hint 1: The build script should be used for all configuration. For in-source developer builds, executing the platform’s make command also works.
*Hint 2: jom, the drop-in replacement of nmake on Windows, doesn’t work right now for top-level builds. You can, however, use it to (re-)build individual submodules.

Building QtWebKit

Linux, Mac

The tools bison, flex and gperf which are required for building.

Windows

WebKit.org [trac.webkit.org] has instructions for building WebKit on Windows. Besides ICU [site.icu-project.org] library , phtreads-win32[sourceware.org] is required. After unzipping a release package (say to c:\phtreads) , you need to:

• Add c:\phtreads\pthreads.2 to the INCLUDE environment variable
• Add c:\phtreads\Pre-built.2\lib\x64 or c:\phtreads\Pre-built.2\lib\x86 to the LIB environment variable
• Add c:\phtreads\Pre-built.2\dll\x64 or c:\phtreads\Pre-built.2\dllx86 to the PATH environment variable

The tools bison, flex and gperf which are required for building are provided for convenience in the folder gnuwin32\bin.

Installing (Linux / Mac OS X)

• Note: Installation is only needed if you haven’t used the configure options -developer-build or -prefix “PWD/qtbase”. Otherwise you can just use Qt from the build directory.

To install, run

But if you’re installing into a non-standard path for testing qt5, you’ll need to set your path to include the installation directory’s bin directory. You should either make sure you don’t have QTDIR set in your environment, or set QTDIR to the installation path before running make install. For example, if installing into /opt/qt5 (this assumes you are using bash; for csh-derived shells you’ll need to run setenv equivalents first):

Cleaning

To really get a clean tree use:

since make confclean no longer works from the top-level of the repo.

Getting updates

To update both the qt5.git repo as well as the submodules to the list of revisions that are known to work, run

If you are planning to do nightly builds, consider using the script qt5_tool that lives in qtrepotools/bin. It provides options for updating the repository, cleaning and building. For example, qt5_tool -u -c -b can be used to clean, update and build. qt5_tool -p -c – b would be used to pull all modules to the head of their master branches.

• Hint1: git submodule update does a hard reset on submodules, potentially getting rid of any local commits you’ve done! If the latter happened to you (and you haven’t been working with branches anyhow), git reflog is your friend ….
• Hint2: When creating scripts for updates on Windows, note that git clean often fails if some process locks a file or folder.

Using master branches in the submodules

By default the checkout will not contain the latest master branches of each individual submodule repository, but a combination of versions that are known to work together. If you want to get the absolute latest stuff you can do so on a per-module basis, e.g.

or use qt5_tool to update all repositories to master:

However, there’s a good chance that compilation will fail due to incompatible versions of submodules! You might want to ask other persons actively working on a module how to resolve these incompatibilities.

Issues

Linux

configure fails with “No QPA platform plugin enabled!” (Linux)

You should install the libxcb and it’s accompanying packages, see ‘System Requirements’.

qmlscene segfaults “Cannot create platform GL context, none of GLX, EGL, DRI2 is enabled” (Linux)

Try installing the libx11-xcb-dev package:

afterwards you have to re-run configure and force qtbase/src/plugins/platforms/xcb to recompile.

WebKit doesn’t compile, missing ICU

Currently there is no configure time check for ICU, so install it through the package manager through

on Ubuntu/Debian:

on Fedora:

Alternatively you can also compile Qt without webkit by deleting / renaming the qtwebkit, qtwebkit-examples-and-demos directories. The -no-webkit option of configure does not work yet : https://bugreports.qt-project.org/browse/QTBUG-20577

Windows

qdeclarative doesn’t compile because of missing v8.lib (Windows)

Compiling v8 in qtbase requires Python. Make sure you have a python.exe in your %PATH%, go to qtjsbackend, run qmake && nmake.

Debugging OpenGL issues (Windows)

Set the environment variable QT_QPA_VERBOSE=gl:1 and run the application with DebugView [technet.microsoft.com] installed. The log will show the requested vs obtained OpenGL version. If the log tells you that it only has OpenGL 1.1, QML2 will not work. Note that qmlscene will not report errors about unsupported OpenGL versions.

Questions & Comments

Please raise questions & comments about this article in the forum : http://developer.qt.nokia.com/forums/viewthread/7018

http://qt-project.org/wiki/Building-Qt-5-from-Git