Introduction to Qt5

Qt5 is a cross-platform application framework that is widely used for developing application software with a graphical user interface (GUI) (in which cases Qt5 is classified as a widget toolkit), and also used for developing non-GUI programs such as command-line tools and consoles for servers.

This package is known to build and work properly using an LFS-7.7 platform.

Package Information

Qt5 Dependencies


Xorg Libraries



GeoClue-0.12.0, gst-plugins-base-1.4.5 (QtWebKit HTML5 Video Support), GTK+-2.24.26 (GTK+ Theme Support), Harfbuzz-0.9.38, IBus, libxkbcommon, MariaDB-10.0.16 or MySQL, PostgreSQL-9.4.1, PulseAudio-5.0, and unixODBC-2.3.2

User Notes: http://wiki.linuxfromscratch.org/blfs/wiki/qt5

Qt Installation Alternatives

The installation of Qt presents several challenges and choices. Complicating the Qt installation is the fact that there are two versions, Qt4 and Qt5, that have executable programs with identical names. If both packages are installed on one system, the only methods to manage which set of programs is used is to either control the users' PATH or to rename files either directly or via symbolic links. Both packages cannot be installed in the same directory.

If you are only going to install one of the Qt versions, the choice of installation methods is easier. You can either install the components in the several directories of the /usr hierarchy or install the entire package in a separate directory of your choice. We refer to these options below as "Method 1: Installing in /usr" and "Method 2: Installing in /opt".

If both versions of Qt are to be installed, one or both versions need to be installed in a separate directory. For the purposes here we use the /opt directory. The selection of which version is being used by individual users on a system is controlled by the PATH variable. Other systems can be designed, but the BLFS editors find the PATH method easiest.

The advantage of installing in /usr is that no updates to the /etc/ld.so.conf or /etc/man_db.conf files are required. The package files are distributed within several subdirectories of the /usr hierarchy. This is the method that most commercial distributions use. The disadvantage for BLFS users is that this Qt instance cannot be upgraded while it is in use. For instance, it cannot be upgraded from a running KDE environment. It also precludes having multiple versions of Qt on your system and does not allow reverting to an existing, known working instance of Qt.

The advantage of installing Qt in a custom directory such as /opt/qt-4.8.6 or /opt/qt-5.4.0 or is that it keeps all the package files consolidated in a dedicated directory hierarchy. By using this method, an update can be made without overwriting a previous installation and users can easily revert to a previous version by changing one symbolic link or merely changing the PATH variable. It also allows a developer to maintain multiple versions of Qt4 or Qt5 for testing.

Installation of Qt5



If you did not install some of the recommended dependencies, examine ./configure --help output to check how to disable them or use internal versions bundled in the source tarball.



If Qt5 is being reinstalled into the same directory as an existing instance, run the commands done by root, such as make install, from a console or non-Qt5 based window manager. It overwrites Qt5 libraries that should not be in use during the install process.

Method 1: Installing in /usr

Install Qt5 by running the following commands:

export QT5LINK=/usr

./configure -prefix         /usr               \
            -sysconfdir     /etc/xdg           \
            -bindir         /usr/bin           \
            -headerdir      /usr/include/qt5   \
            -archdatadir    /usr/lib/qt5       \
            -datadir        /usr/share/qt5     \
            -docdir         /usr/share/doc/qt5 \
            -translationdir /usr/share/qt5/translations \
            -examplesdir    /usr/share/doc/qt5/examples \
            -confirm-license   \
            -opensource        \
            -dbus-linked       \
            -openssl-linked    \
            -system-sqlite     \
            -no-nis            \
            -skip qtwebengine  \
            -nomake examples   \
            -optimized-qmake   &&

This package does not come with a test suite.

Remove references to the build directory from the .pc files by running the following command:

find . -name "*.pc" -exec perl -pi -e "s, -L$PWD/?\S+,,g" {} \;

Now, as the root user:

make install

Remove references to the build directory from installed files by running the following commands as the root user:

sed -e "s:$PWD/qtbase:/usr/lib/qt5:g" \
    -i /usr/lib/qt5/mkspecs/modules/qt_lib_bootstrap_private.pri &&

find /usr/lib/lib{qgsttools_p,Qt5*}.prl -exec sed -i -r \
     '/^QMAKE_PRL_BUILD_DIR/d;s/(QMAKE_PRL_LIBS =).*/\1/' {} \;

Method 2: Installing in /opt/qt-5.4.0

This section provides instructions for installing Qt5 in the /opt directory.

export QT5DIR=/opt/qt-5.4.0 &&
export QT5LINK=/opt/qt5 &&

./configure -prefix     $QT5DIR  \
            -sysconfdir /etc/xdg \
            -confirm-license     \
            -opensource          \
            -dbus-linked         \
            -openssl-linked      \
            -system-sqlite       \
            -no-nis              \
            -nomake examples     \
            -skip qtwebengine    \
            -optimized-qmake     &&

Now, as the root user:

make install &&
ln -svfn $QT5DIR /opt/qt5

Remove references to the build directory from installed files by running the following commands as the root user:

find $QT5DIR -name qt_lib_bootstrap_private.pri \
   -exec sed -i -e "s:$PWD/qtbase:/$QT5DIR/lib/:g" {} \; &&

find $QT5DIR -name \*.prl \
   -exec sed -i -e '/^QMAKE_PRL_BUILD_DIR/d' {} \;

Continuing for Both Methods

For all methods, install images and create the menu entries for installed applications. Be sure that the QT5LINK variable is defined in root's environment and as the root user:

install -v -dm755 /usr/share/pixmaps/                  &&

install -v -Dm644 qttools/src/assistant/assistant/images/assistant-128.png \
                  /usr/share/pixmaps/assistant-qt5.png &&

install -v -Dm644 qttools/src/designer/src/designer/images/designer.png \
                  /usr/share/pixmaps/designer-qt5.png  &&

install -v -Dm644 qttools/src/linguist/linguist/images/icons/linguist-128-32.png \
                  /usr/share/pixmaps/linguist-qt5.png  &&

install -v -Dm644 qttools/src/qdbus/qdbusviewer/images/qdbusviewer-128.png \
                  /usr/share/pixmaps/qdbusviewer-qt5.png &&

install -dm755 /usr/share/applications &&

cat > /usr/share/applications/assistant-qt5.desktop << EOF
[Desktop Entry]
Name=Qt5 Assistant 
Comment=Shows Qt5 documentation and examples

cat > /usr/share/applications/designer-qt5.desktop << EOF
[Desktop Entry]
Name=Qt5 Designer
GenericName=Interface Designer
Comment=Design GUIs for Qt5 applications

cat > /usr/share/applications/linguist-qt5.desktop << EOF
[Desktop Entry]
Name=Qt5 Linguist
Comment=Add translations to Qt5 applications

cat > /usr/share/applications/qdbusviewer-qt5.desktop << EOF
[Desktop Entry]
Name=Qt5 QDbusViewer 
GenericName=D-Bus Debugger
Comment=Debug D-Bus applications

Command Explanations

-confirm-license: Accept license without prompting user during configuration.

-opensource: Install the opensource version of Qt.

-release: This switch disables building with debugging symbols.

-nomake examples: This switch disables building of the example programs included in the source tarball. Remove it if you want to build them.

-system-sqlite: This switch enables use of the system version of SQLite.

-no-nis: This switch disables support for Network Information Service (NIS) which has been removed from recent versions of Glibc.

-dbus-linked -openssl-linked: These switches enable explicit linking of the D-Bus and OpenSSL libraries into Qt5 libraries instead of dlopen()-ing them.

-skip qtwebengine: This switch disables building the Qt Web Engine. It is not presently used by any applications. If this option is removed, fix a build problem with:

sed -i '$ a !contains(QT_CONFIG, pulseaudio): GYP_CONFIG += use_pulseaudio=0' \

-optimized-qmake: This switch enables building of the optimized qmake program.

-system-harfbuzz: This switch enables use of the system version of Harfbuzz which fixes some font rendering issues in Qt5 applications but doesn't have all the features that the included one has.

Configuring Qt5

Configuration Information

Create the menu entries for installed applications by running the following commands root user:

If you installed Qt5 in /usr, create an environment variable needed by certain packages. As the root user:

cat > /etc/profile.d/qt5.sh << EOF
# Begin /etc/profile.d/qt5.sh

export QT5DIR

# End /etc/profile.d/qt5.sh

If you installed Qt5 in a location other than /usr, you need to update the following configuration files so that Qt5 is correctly found by other packages and system processes.

As the root user, update the /etc/ld.so.conf file and the dynamic linker's run-time cache file:

cat >> /etc/ld.so.conf << EOF
# Begin Qt addition


# End Qt addition


As the root user, create the /etc/profile.d/qt5.sh file:

cat > /etc/profile.d/qt5.sh << EOF
# Begin /etc/profile.d/qt5.sh


pathappend /opt/qt5/bin           PATH
pathappend /opt/qt5/lib/pkgconfig PKG_CONFIG_PATH

export QT5DIR

# End /etc/profile.d/qt5.sh

Choosing Qt Program Versions

If you install both Qt4 and Qt5, you can use some simple scripts to select the currently active set of Qt programs. As the root user, create the following scripts:

cat > /usr/bin/setqt4 << 'EOF'
if [ "x$QT5DIR" != "x/usr" ]; then pathremove  $QT5DIR/bin; fi
if [ "x$QT4DIR" != "x/usr" ]; then pathprepend $QT4DIR/bin; fi
echo $PATH
cat > /usr/bin/setqt5 << 'EOF'
if [ "x$QT4DIR" != "x/usr" ]; then pathremove  $QT4DIR/bin; fi
if [ "x$QT5DIR" != "x/usr" ]; then pathprepend $QT5DIR/bin; fi
echo $PATH

You should now be able to use the appropriate Qt version by running source setqt4 or source setqt5 as desired. (Setting the PATH wont work in a subshell.) Another technique that can be used is to create appropriate alias additions to your ~/.bashrc like alias setqt4='source setqt4'.


Installed Programs: assistant, designer, lconvert, linguist, lrelease, lupdate, moc, pixeltool, qcollectiongenerator, qdbuscpp2xml, qdbus, qdbusviewer, qdbusxml2cpp, qdoc, qhelpconverter, qhelpgenerator, qlalr, qmake, qml1plugindump, qmlbundle, qmlimportscanner, qmlmin, qmlplugindump, qmlprofiler, qml, qmlscene, qmltestrunner, qmlviewer, qtdiag, qtpaths, rcc, syncqt.pl, uic, xmlpatterns, and xmlpatternsvalidator
Installed Libraries: libEnginio.so, libqgsttools_p.so, libQt5Bluetooth.so, libQt5Bootstrap.a, libQt5CLucene.so, libQt5Concurrent.so, libQt5Core.so, libQt5DBus.so, libQt5Declarative.so, libQt5DesignerComponents.so, libQt5Designer.so, libQt5Gui.so, libQt5Help.so, libQt5MultimediaQuick_p.so, libQt5Multimedia.so, libQt5MultimediaWidgets.so, libQt5Network.so, libQt5Nfc.so, libQt5OpenGLExtensions.a, libQt5OpenGL.so, libQt5PlatformSupport.a, libQt5Positioning.so, libQt5PrintSupport.so, libQt5QmlDevTools.a, libQt5Qml.so, libQt5QuickParticles.so, libQt5QuickWidgets.so, libQt5Quick.so, libQt5QuickTest.so, libQt5Script.so, libQt5ScriptTools.so, libQt5Sensors.so, libQt5SerialPort.so, libQt5Sql.so, libQt5Svg.so, libQt5Test.so, libQt5UiTools.a, libQt5WebKit.so, libQt5WebKitWidgets.so, libQt5WebSockets.so, libQt5Widgets.so, libQt5X11Extras.so, libQt5XmlPatterns.so, libQt5Xml.so, and several plugins under /opt/qt5/{imports,plugins,qml}
Installed Directories: /usr/include/qt5, /usr/lib/qt5, /usr/share/doc/qt5, and /usr/share/qt5 OR /opt/qt5 and /opt/qt-5.4.0

Short Descriptions


is a tool for presenting on-line documentation.


is a full-fledged GUI builder. It includes powerful features such as preview mode, automatic widget layout, support for custom widgets, and an advanced property editor.


provides support for translating applications into local languages.


is a simple command line tool. It reads a Qt project file and produces message files used by the application.


reads a Qt project file, finds the translatable strings in the specified source, header and Qt Designer interface files, and produces or updates the translation files listed in the project file.


generates Qt meta object support code.


is a desktop magnifier and as you move your mouse around the screen it will show the magnified contents in its window.


uses information stored in project files to determine what should go in the makefiles it generates.


is a resource compiler used in conjunction with designer.


is a Qt user interface compiler.

Last updated on 2015-03-02 22:33:58 +0000