Provided by: libqwt-doc_6.1.4-2build2_all 
NAME
qwtinstall - Installing Qwt
Download
Stable Qwt releases are available from the Qwt project page.
Qwt-6.1.4 consists of 4 files:
• qwt-6.1.4.zip
Zip file with the Qwt sources and the html documentation for Windows
• qwt-6.1.4.tar.bz2
Compressed tar file with the Qwt sources and the html documentation for UNIX systems (
Linux, Mac, ... )
• qwt-6.1.4.pdf
Qwt documentation as PDF document.
• qwt-6.1.4.qch
Qwt documentation as Qt Compressed Help document, that can be loaded into the Qt
Assistant or Creator. In the Qt Creator context sensitive help will be available like
for Qt classes.
Precompiled Qwt Designer plugins, that are compatible with some binary packages of the Qt
Creator:
• qwtdesigner-6.1.4-*.zip
Installing Qwt
Beside headers, libraries and the html version of the class documentation a proper Qwt
installation contains a Designer plugin and a Qwt features file for building applications
using Qwt.
All files will be copied to an installation directory, that is configurable by editing
qwtconfig.pri. Its default settings is:
• Windows
C:\Qwt-6.1.4
• Unix like systems
/usr/local/qwt-6.1.4
For the rest of the document this install path will be written as ${QWT_ROOT} and needs to
be replaced by the real path in all commands below.
It is not unlikely, to have more than one installation of Qwt on the same system. F.e for
using the Qwt Designer plugin in the Qt Creator a version of Qwt is necessary with the
same Qt and compiler combination, that had been used for building the Qt Creator ( see
'Help->About Qt Creator ...' ).
Installing Qwt is done in 3 steps, that are quite common on UNIX systems.
1. Configuration
In the configuration step all parameters are set to control how to build and install
Qwt
2. Build
In the build step binaries are built from the source files.
3. Installation
The installation copies and rearranges all files that are necessary to build Qwt
applications to a target directory.
The installation doesn't modify the system beside copying files to a directory in a proper
way. After removing build and installation directories the system is in the same state as
it was before.
Configuration
Configuring Qwt has to be done by editing the Project files used for building:
• qwtbuild.pri
qwtbuild.pri contains settings for how to build Qwt. All settings of this file are only
for building Qwt itself and doesn't have an impact on how an application using Qwt is
built. Usually its default settings doesn't need to be modified.
• qwtconfig.pri
qwtconfig.pri defines what modules of Qwt will be built and where to install them.
qwtconfig.pri gets installed together with the Qwt features file qwt.prf and all its
settings are known to project files for building Qwt applications.
In qwtconfig.pri the meaning of each option is explained in detail - it's worth reading it
before running into problems later.
Build and installation
The Qt Creator is a graphical frontend for calling qmake/make and - technically - it could
be used for building and installing Qwt. But as this way requires a lot more understanding
of details the following step by step instructions are for the easier way using the
command line.
Unix-like systems
The first step before creating the Makefile is to check that the correct version of qmake
is used. F.e. on older Linux distribution you often find a Qt3 qmake and in the path.
The default setting of qmake is to generate a makefile that builds Qwt for the same
environment where the version of qmake has been built for. So creating a makefile usually
means something like:
cd qwt-6.1.4
/usr/local/Qt-5.0.1/bin/qmake qwt.pro
The generated Makefile includes all paths related to the chosen Qt version and the next
step is:
make
( On multicore systems you can speed up building the Qwt libraries with running several
jobs simultaneously: f.e. 'make -j4' on a dual core. )
Finally you have to install everything below the directories you have specified in
qwtconfig.pri. Usually this is one of the system directories ( /usr/local, /opt, ... )
where you don't have write permission and then the installation needs to be done as root:
sudo make install
( On systems where sudo is not supported you can do the same with: su -c 'make install' )
Windows
Qt packages offer a command line interface, that can be found in the Qt application menu:
f.e 'All Programs -> Qt -> Command Prompt'. It is not mandatory to use it, but probably
the easiest way as it offers an environment, where everything is initialized for a version
of Qt ( f.e qmake is in the PATH ).
Creating a makefile usually means something like:
cd qwt-6.1.4
qmake qwt.pro
The generated makefile includes all paths related to the chosen Qt version.
MinGW
For MinGW builds the name of the make tool is 'mingw32-make'
mingw32-make
( On multicore systems you can speed up building the Qwt libraries with running several
jobs simultaneously: 'mingw32-make -j' )
Finally you have to install everything below the directories you have specified in
qwtconfig.pri.
mingw32-make install
MSVC
For MSVC builds the name of the make tool is 'nmake'. Alternatively it is possible to use
'jom' ( https://wiki.qt.io/Jom ), that is usually included in a Qt Creator package.
nmake
Finally you have to install everything below the directories you have specified in
qwtconfig.pri.
nmake install
Qwt and the Qt tool chain
Designer plugin
The Designer plugin and the corresponding Qwt library ( if the plugin has not been built
self containing ) have to be compatible with Qt version of the application loading it (
usually the Qt Creator ) - what is often a different version of the Qt libraries you want
to build your application with. F.e on Windows the Qt Creator is usually built with a MSVC
compiler - even if included in a MinGW package !
To help Qt Designer/Creator with locating the Qwt Designer plugin you have to set the
environment variable QT_PLUGIN_PATH, modify qt.conf - or install the plugin to one of the
application default paths.
The Qt documentation explains all options in detail:
• https://doc.qt.io/qt-5/deployment-plugins.html
• https://doc.qt.io/qtcreator/adding-plugins.html
F.e. on a Linux system you could add the following lines to .bashrc:
QT_PLUGIN_PATH="${QWT_ROOT}/plugins:$QT_PLUGIN_PATH"
export QT_PLUGIN_PATH
When the plugin has not been built including the Qwt library ( see
QwtDesignerSelfContained in qwtconfig.pri ) the Qt Designer/Creator also needs to locate
the Qwt libraries. On Unix systems the path to the installed library is compiled into the
plugin ( see rpath, ldd ), but on Windows the Qt Creator needs to be configured ( (
Running a Qwt application ) in the same way as for any application using Qwt.
In case of problems the diagnostics of Qt Creator and Designer are very limited ( usually
none ), but setting the environment variable QT_DEBUG_PLUGINS might help. In the Qt
Creator it is possible to check which plugins were loaded successfully and for certain
problems it also lists those that were recognized but failed ( Tools > Form Editor > About
Qt Designer Plugins ).
Online Help
The Qwt class documentation can be loaded into the Qt Creator:
• open the settings dialog from the Tools->Options menu
• raise the tab 'Help->Documentation'.
• press the Add button and select qwt-6.1.4.qch.
Now the context sensitive help ( F1 ) works for Qwt classes.
For browsing the documentation in the Qt Assistant:
• open the settings dialog from the Edit->Preferences menu
• raise the tab Documentation.
• press the Add button and select qwt-6.1.4.qch.
Building a Qwt application
All flags and settings that are necessary to compile and link an application using Qwt can
be found in the file ${QWT_ROOT}/features/qwt.prf.
When using qmake it can included from the application project file in 2 different ways:
• Adding Qwt as qmake feature
When using the qmake feature mechanism you can bind a special version of qmake to a
special installation of Qwt without having to add this dependency to the application
project. How to add Qwt as feature is documented in the qmake docs.
After adding Qwt as a feature f.e on Linux as a persistent property ....
qmake -set QMAKEFEATURES ${QWT_ROOT}/features
.. the following line can be added to the application project file:
CONFIG += qwt
• Including qwt.prf in the application project file
Instead of using qwt.prf as qmake feature it can be included from the application
project file:
include ( ${QWT_ROOT}/features/qwt.prf )
The advantage of using a direct include is, that all settings of qwt.prf are known to the
application project file ( qmake features are included after the application project file
has been parsed ) and it can be implemented depending on - f.e. settings made in
qwtconfig.pri.
On Unix platforms it is possible to link a runtime path into the executable, so that the
location of the Qwt libraries can be found without having to configure a runtime
environment:
• QMAKE_LFLAGS_RPATH
• QMAKE_RPATH
• QMAKE_RPATHDIR
Running a Qwt application
When using Qwt as shared library ( DLL ) the dynamic linker has to find it according to
the rules of the operating system.
Windows
The only reasonable way to configure the runtime environment - without having to copy the
Qwt libraries around - is to modify the PATH variable. F.e. this could be done by adding
the following line to some batch file:
set PATH=%PATH%;${QWT_ROOT}
GNU/Linux
Read the documentation about:
• ldconfig
• /etc/ld.so.conf
• LD_LIBRARY_PATH
Using the ldd command a configuration can be tested.