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428 lines
15 KiB
428 lines
15 KiB
/*!
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\page faq.html
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\title The TQt FAQ
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See also the \link commonproblems.html Technical FAQ\endlink.
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\tableofcontents
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<hr>
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\section1 General Questions
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<hr width="30%">
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\section2 What is Qt?
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Qt is a multiplatform C++ GUI toolkit. It
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provides application developers with all the functionality
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needed to build applications with state-of-the-art graphical
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user interfaces. TQt is fully object-oriented, easily
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extensible, and allows true component programming.
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Qt is supported on the following platforms:
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\list
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\i <b>MS/Windows</b> -- 95, 98, NT 4.0, ME, 2000, and XP
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\i <b>Unix/X11</b> -- Linux, Sun Solaris, HP-UX, Compaq Tru64 UNIX,
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IBM AIX, SGI IRIX and a wide range of others
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\i <b>Macintosh</b> -- Mac OS X
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\i <b>Embedded</b> -- Linux platforms with framebuffer support.
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\endlist
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It has become the emerging standard development
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environment for IT professionals who want to:
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\list
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\i Write (and maintain) a single source-tree.
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\i Port their applications to multiple platforms with a simple
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recompilation.
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\i Internationalize their applications.
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\i Provide their applications with native look and feel.
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\i Have their applications run at native speed.
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\endlist
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<hr width="30%">
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\section2 What is Trolltech?
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Trolltech is an international software company with
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headquarters in Oslo, the capital of Norway, and with offices
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in Brisbane, Australia, and Redwood City, California. Our
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flagship product is Qt, the multi-platform C++ GUI toolkit.
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Trolltech ASA was founded in 1994, although, the core team of designers
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started Qt's development in 1992.
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More details can be found at \link troll.html Trolltech\endlink.
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<hr width="30%">
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\section2 How can I evaluate Qt?
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We offer 30 day evaluation versions of TQt on all our supported platforms.
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Further details can be found here: \l http://www.trolltech.com/evaluate.html.
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<hr width="30%">
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\section2 What does TQt cost?
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This depends on your number of developers, on how many
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different platforms you target, and on the edition of TQt you
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choose. Currently we offer two different editions (Enterprise
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Edition and Professional Edition) on four different
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platforms (Microsoft Window, Unix/X11, Macintosh and Linux/embedded).
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We also offer discounts for academic and research institutions.
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Details on pricing can be found here:
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\l http://www.trolltech.com/pricing.html.
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<hr width="30%">
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\section2 How can I buy Qt?
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To purchase, please visit the <a
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href="https://webshop.trolltech.com/cgi-bin/index.cgi">Trolltech
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webshop</a>. In the webshop, you can generate a Purchase Order, order
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a Quote, or purchase directly using a credit card.
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For further information and assistance, please contact Trolltech sales:
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Email: \link mailto:sales@trolltech.com sales@trolltech.com\endlink
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Phone, US office (for North America): <strong>(+1) 650-813-1676</strong>
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Phone, Norway office (for others): <strong>+47 2160 4800</strong>
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<hr width="30%">
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\section2 What kind of technical support is available for Qt?
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Trolltech offers email support to commercial licensees. The first year
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of Trolltech's Support and Maintenance Service is included with the
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purchase of TQt Professional and TQt Enterprise Edition licenses.
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Licenses can be kept up-to-date and fully supported by buying
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the Support and Maintenance Service for the licenses held in each
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subsequent year.
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For further information see here:
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\l http://www.trolltech.com/support/.
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<hr width="30%">
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\section2 Who provides training for Qt?
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A number of companies provide TQt training, in Asia, Europe and the US.
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Trolltech has agreements with a number of official training
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partners, who offer Trolltech approved courses. In addition
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there are a number of independently developed courses run by third
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parties. You can find more information about the partners and the
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courses here: \l http://www.trolltech.com/training/.
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<hr width="30%">
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\section2 Who provides consultancy for Qt?
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A number of companies provide consultancy services for TQt and
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Qtopia. You can find a partial list here:
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\l http://www.trolltech.com/company/servicepartners.html.
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<hr width="30%">
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\section2 Are there any books about TQt programming?
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Yes, there are quite a few books on Qt, most of them
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available from amazon.com. You can find a partial list at
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\l http://www.trolltech.com/developer/books.html.
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The official TQt book is
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<a href="http://www.amazon.com/exec/obidos/ASIN/0131240722/trolltech/">C++ GUI Programming with TQt 3</a>.
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<hr width="30%">
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\section2 What is the Open Source Edition?
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The TQt Open Source Edition is our non-commercial versions of
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Qt. You can use this edition to create and run free
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software, i.e. software that is licensed under the GNU GPL or
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a similarly recognized open source license.
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Qt Open Source edition is available for Unix/X11, Macintosh and
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Linux/embedded.
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<hr width="30%">
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\section2 What is the idea behind having a free version of Qt?
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With the Open Source Edition, Trolltech has found a way to support
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the free software concept. Part of our commitment is to enable
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those who contribute to the free software pool to do so
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without paying license fees.
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<hr width="30%">
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\section2 Is there a low-cost version of TQt for writing shareware?
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No, but Qt's commercial licenses permit you to write and sell
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shareware written with Qt.
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<hr>
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\section1 Questions about Qt's Users
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<hr width="30%">
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\section2 How many developers use Qt?
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We don't know! We can count our many thousands of commercial
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licensees, but the number of free software developers
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using TQt can only be guessed based on download figures, book
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sales, the number of open source TQt applications available on
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the web, Universities teaching with Qt, and other factors. A
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conservative estimate would put the figure at around 100,000 to
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150,000 developers world-wide.
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<hr width="30%">
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\section2 Which major corporations use Qt?
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See our list of reference customers at
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\l http://www.trolltech.com/company/customers.html. Note that many
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commercial customers do not disclose their use of TQt because they see
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Qt as a competitive advantage.
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<hr width="30%">
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\section2 Are there any well-known applications that use Qt?
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There are many, e.g. Adobe Photoshop Album from Abobe
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Corporation and the KDE desktop. A partial list can be found at
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\l http://www.trolltech.com/products/qt/apps-using-ntqt.html
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<hr>
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\section1 Questions about Developing Applications with Qt
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<hr width="30%">
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\section2 Is there a mailing list for Qt?
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Trolltech operates several mailing lists for TQt users including
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\c qt-announce, \c qt-interest and \c snapshot-users.
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See \link http://lists.trolltech.com Mailing lists\endlink.
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<hr width="30%">
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\section2 Is Qt's documentation available online?
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Yes, at \l http://doc.trolltech.com.
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<hr width="30%">
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\section2 Is there a technical newsletter for Qt?
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Yes, \link http://doc.trolltech.com/qq/index.html Qt
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Quarterly\endlink. It is a paper-based newsletter exclusively
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available to TQt licensees.
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As a courtesy and convenience to all our users, a selection of
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articles is also published online about one month after publication.
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<hr width="30%">
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\section2 I think I have found a bug in Qt. Where can I report it?
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Bugs should be reported to \link mailto:qt-bugs@trolltech.com
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qt-bugs@trolltech.com\endlink. But \e please read (the very short)
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\link bughowto.html How to Report a Bug\endlink page \e first.
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<hr>
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\section1 Questions about Professional Licensing
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<hr width="30%">
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\section2 We have purchased a license, but the developer is leaving the company
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project. Can we transfer the license to another developer?
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Yes. TQt licences are for the individual use of named developers. If
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the developer associated with a licence leaves the organization, or
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moves on to another project that does not require a TQt license,
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another developer can take over the licence. You can change the name
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of the developer using a licence at any time, but after a change you
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must wait at least six (6) months before changing again.
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<hr width="30%">
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\section2 Can I purchase floating licenses for Qt?
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No, we do not offer floating licenses.
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The reason is this: Floating licenses are based on the concept
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of defining a maximum number of concurrent users. For example,
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for a word processor, this means the maximum number of
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instances of that application that can be running at any
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time. However, for a library product like Qt, there is no main
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application that is always running when the product is being
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used. Hence, it is not possible to count the number of
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concurrent users, and therefore floating licenses do not
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make sense.
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\omit
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#if 0 // ##### Just an idea, no clue if this is policy today
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While we want to develop our software for multiple platforms, some
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of our developers will only need to work on a single platform. Can
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we purchase single packs for those?
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No, you can only purchase single packs as long as you target
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one platform only.
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#endif
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\endomit
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<hr width="30%">
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\section2 Can we use the Open Source Edition while developing our non-free
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application and then purchase commercial licenses when we start to
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sell it?
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No: our commercial license agreements only apply to software
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that was developed with TQt under the agreement. They do not
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apply to code that was developed with the TQt Open Source Edition
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prior to the agreement. Any software developed with Qt
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without a commercial license agreement must be released as
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free/open source software.
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<hr>
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\section1 Questions about Open Source Software Licensing
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<hr width="30%">
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\section2 I just want to run KDE and other Qt-based software on my
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machine. Can I do that with the Open Source Edition?
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Yes. You may use the TQt Open Source Edition for running applications,
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both at home and at work, without restrictions.
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<hr width="30%">
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\section2 I want to put Qt, and applications that use it, on a CD-ROM or on
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a web site. Can I do that with the Open Source Edition?
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Yes. You may copy and redistribute the TQt Open Source Edition, both
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at home and at work, without restrictions.
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<hr width="30%">
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\section2 Can I make software with the TQt Open Source Edition and release it under
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the GNU GPL, BSD, or Artistic license?
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Yes. The GNU GPL, GPL-compatible licenses, or any other
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approved open source license will do. The FSF.org and
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OpenSource.org web sites list approved software licenses.
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<hr width="30%">
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\section2 I don't want to give away my source code. What do I do?
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You need to buy a commercial TQt license.
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<hr width="30%">
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\section2 Is software based on the TQt Open Source Edition really free? Does it
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carry any Trolltech-specific license restrictions?
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Yes, it really is free. This is because the TQt Open Source Edition
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uses the GNU GPL, which forbids the imposition of any license
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restrictions on software based on the Open Source Edition that would
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make it non-free. And no, there are no Trolltech-specific
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license restrictions on software produced using the Open Source
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Edition.
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<hr width="30%">
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\section2 What if Trolltech stops releasing Open Source Editions of Qt?
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We have absolutely no intention of doing that. Together with
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the K Desktop Environment project, we have set up the KDE Free
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Qt Foundation (see
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\l http://www.kde.org/whatiskde/kdefreeqtfoundation.php) to
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legally guarantee the availability of TQt for free software
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development now and forever - even if circumstances beyound
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our control prevent us from producing new free editions.
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<hr width="30%">
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\section2 Using the Open Source Edition, can I make non-free software for internal
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use in my company/organization?
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No. Software developed with the Open Source Edition is always free
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software, i.e. it can only be distributed under a free
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software license. In particular, all the source code for all
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the modules your software is based on, regardless of whether
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they have been written by you or by others, must be free
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software. This is part of our commitment to the free software
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community, and enables those who contribute to the free
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software pool to do so without paying license fees.
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Although it is possible to write free software for internal
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use, it is difficult to ensure that such software is used and
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distributed legally. For example, if your free software
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requires any modules that impose conditions on you that
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contradict the conditions of the GNU GPL, including, but not
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limited to, software patents, commercial license agreements,
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copyrighted interface definitions or any sort of
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non-disclosure agreement, then you cannot distribute it at
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all; hence it cannot be given to consultants, employees for
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their personal computers, subsidiaries, other divisions, or
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even to new owners.
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Consequently we recommend using commercial licenses for all
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internal software development.
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<hr width="30%">
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\section2 Is TQt Open Source Edition really free software in the GNU meaning of the
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word?
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Yes - it is free software both as in "no cost" and as in
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"free speech". Even more, it is actually available under the
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terms of the GNU GPL. This means you can link GPL'ed software
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to it, and you can take code from TQt and put it into other
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GPL'ed software.
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<hr width="30%">
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\section2 If the Open Source Edition is GNU GPL, aren't there license conflicts
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with incompatible open source licenses? How come people can even
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run commercial software like the Opera web browser with it?
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If the Open Source Edition was licensed purely under the GNU GPL,
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there would be problems. However, as long as Qt-based
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software is either open source or was developed under a
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commercial license agreement with Trolltech, we grant
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permission to compile, link and run those programs with the
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Open Source Edition. This is written down in our second free software
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license, the QPL.
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<hr width="30%">
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\section2 Doesn't such an en extra license in addition to the GNU GPL
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violate the terms of the GPL or at least make the whole package
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GPL-incompatible?
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No, because those extra license terms give you rights in
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addition to those of the GNU GPL, including the right to
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remove those extra terms.
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<hr width="30%">
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\section2 Why is TQt Open Source Edition not distributed under the GNU Lesser
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General Public License (LGPL)?
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The LGPL is designed to "permit developers of non-free
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programs to use free libraries" (quote from the LGPL). In
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other words, if TQt Open Source Edition were LGPL'd, companies would
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not have to purchase our commercial editions in order to make
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commercial/proprietary software, they could just use the Open Source
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Edition, free of charge. That would mean Trolltech would not
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get the revenue necessary for improving and extending Qt.
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Note also that the Free Software Foundation discourages the
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use of the LGPL.
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<hr>
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\section1 Questions about other programming languages
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<hr width="30%">
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\section2 Are there bindings to languages other than C++?
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Yes there are, e.g. bindings to Perl (PerlQt) and Python
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(PyQt). These bindings were written by the open source
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community and are not supported by Trolltech.
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<hr width="30%">
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\section2 Can I develop commercial applications with PerlQt or PyQt or other
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Qt wrappers?
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Yes, if you have purchased a commercial license. The licensing
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conditions are the same whether you use the TQt API directly in
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C++, or you use it through some API wrapper in another
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programming language. All developers that write code
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containing calls to the TQt API (directly or through a wrapper)
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need TQt licenses.
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*/
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