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| author | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2011-07-10 15:24:15 -0500 |
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| committer | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2011-07-10 15:24:15 -0500 |
| commit | bd0f3345a938b35ce6a12f6150373b0955b8dd12 (patch) | |
| tree | 7a520322212d48ebcb9fbe1087e7fca28b76185c /doc/html/faq.html | |
| download | qt3-bd0f3345a938b35ce6a12f6150373b0955b8dd12.tar.gz qt3-bd0f3345a938b35ce6a12f6150373b0955b8dd12.zip | |
Add Qt3 development HEAD version
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diff --git a/doc/html/faq.html b/doc/html/faq.html new file mode 100644 index 0000000..ff21fba --- /dev/null +++ b/doc/html/faq.html @@ -0,0 +1,502 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> +<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/doc/faq.doc:1 --> +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> +<title>The Qt FAQ</title> +<style type="text/css"><!-- +fn { margin-left: 1cm; text-indent: -1cm; } +a:link { color: #004faf; text-decoration: none } +a:visited { color: #672967; text-decoration: none } +body { background: #ffffff; color: black; } +--></style> +</head> +<body> + +<table border="0" cellpadding="0" cellspacing="0" width="100%"> +<tr bgcolor="#E5E5E5"> +<td valign=center> + <a href="index.html"> +<font color="#004faf">Home</font></a> + | <a href="classes.html"> +<font color="#004faf">All Classes</font></a> + | <a href="mainclasses.html"> +<font color="#004faf">Main Classes</font></a> + | <a href="annotated.html"> +<font color="#004faf">Annotated</font></a> + | <a href="groups.html"> +<font color="#004faf">Grouped Classes</font></a> + | <a href="functions.html"> +<font color="#004faf">Functions</font></a> +</td> +<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>The Qt FAQ</h1> + + +<p> +<p> See also the <a href="commonproblems.html">Technical FAQ</a>. +<p> <!-- toc --> +<ul> +<li><a href="#1"> General Questions +</a> +<ul> +<li><a href="#1-1"> What is Qt? +</a> +<li><a href="#1-2"> What is Trolltech? +</a> +<li><a href="#1-3"> How can I evaluate Qt? +</a> +<li><a href="#1-4"> What does Qt cost? +</a> +<li><a href="#1-5"> How can I buy Qt? +</a> +<li><a href="#1-6"> What kind of technical support is available for Qt? +</a> +<li><a href="#1-7"> Who provides training for Qt? +</a> +<li><a href="#1-8"> Who provides consultancy for Qt? +</a> +<li><a href="#1-9"> Are there any books about Qt programming? +</a> +<li><a href="#1-10"> What is the Open Source Edition? +</a> +<li><a href="#1-11"> What is the idea behind having a free version of Qt? +</a> +<li><a href="#1-12"> Is there a low-cost version of Qt for writing shareware? +</a> +</ul> +<li><a href="#2"> Questions about Qt's Users +</a> +<ul> +<li><a href="#2-1"> How many developers use Qt? +</a> +<li><a href="#2-2"> Which major corporations use Qt? +</a> +<li><a href="#2-3"> Are there any well-known applications that use Qt? +</a> +</ul> +<li><a href="#3"> Questions about Developing Applications with Qt +</a> +<ul> +<li><a href="#3-1"> Is there a mailing list for Qt? +</a> +<li><a href="#3-2"> Is Qt's documentation available online? +</a> +<li><a href="#3-3"> Is there a technical newsletter for Qt? +</a> +<li><a href="#3-4"> I think I have found a bug in Qt. Where can I report it? +</a> +</ul> +<li><a href="#4"> Questions about Professional Licensing +</a> +<ul> +<li><a href="#4-1"> We have purchased a license, but the developer is leaving the company +project. Can we transfer the license to another developer? +</a> +<li><a href="#4-2"> Can I purchase floating licenses for Qt? +</a> +<li><a href="#4-3"> Can we use the Open Source Edition while developing our non-free +application and then purchase commercial licenses when we start to +sell it? +</a> +</ul> +<li><a href="#5"> Questions about Open Source Software Licensing +</a> +<ul> +<li><a href="#5-1"> I just want to run KDE and other Qt-based software on my +machine. Can I do that with the Open Source Edition? +</a> +<li><a href="#5-2"> I want to put Qt, and applications that use it, on a CD-ROM or on +a web site. Can I do that with the Open Source Edition? +</a> +<li><a href="#5-3"> Can I make software with the Qt Open Source Edition and release it under +the GNU GPL, BSD, or Artistic license? +</a> +<li><a href="#5-4"> I don't want to give away my source code. What do I do? +</a> +<li><a href="#5-5"> Is software based on the Qt Open Source Edition really free? Does it +carry any Trolltech-specific license restrictions? +</a> +<li><a href="#5-6"> What if Trolltech stops releasing Open Source Editions of Qt? +</a> +<li><a href="#5-7"> Using the Open Source Edition, can I make non-free software for internal +use in my company/organization? +</a> +<li><a href="#5-8"> Is Qt Open Source Edition really free software in the GNU meaning of the +word? +</a> +<li><a href="#5-9"> If the Open Source Edition is GNU GPL, aren't there license conflicts +with incompatible open source licenses? How come people can even +run commercial software like the Opera web browser with it? +</a> +<li><a href="#5-10"> Doesn't such an en extra license in addition to the GNU GPL +violate the terms of the GPL or at least make the whole package +GPL-incompatible? +</a> +<li><a href="#5-11"> Why is Qt Open Source Edition not distributed under the GNU Lesser +General Public License (LGPL)? +</a> +</ul> +<li><a href="#6"> Questions about other programming languages +</a> +<ul> +<li><a href="#6-1"> Are there bindings to languages other than C++? +</a> +<li><a href="#6-2"> Can I develop commercial applications with PerlQt or PyQt or other +Qt wrappers? +</a> +</ul> +</ul> +<!-- endtoc --> + +<p> <hr> +<h2> General Questions +</h2> +<a name="1"></a><p> <hr width="30%"> +<h3> What is Qt? +</h3> +<a name="1-1"></a><p> Qt is a multiplatform C++ GUI toolkit. It +provides application developers with all the functionality +needed to build applications with state-of-the-art graphical +user interfaces. Qt is fully object-oriented, easily +extensible, and allows true component programming. +<p> Qt is supported on the following platforms: +<p> <ul> +<li> <b>MS/Windows</b> -- 95, 98, NT 4.0, ME, 2000, and XP +<li> <b>Unix/X11</b> -- Linux, Sun Solaris, HP-UX, Compaq Tru64 UNIX, +IBM AIX, SGI IRIX and a wide range of others +<li> <b>Macintosh</b> -- Mac OS X +<li> <b>Embedded</b> -- Linux platforms with framebuffer support. +</ul> +<p> It has become the emerging standard development +environment for IT professionals who want to: +<p> <ul> +<li> Write (and maintain) a single source-tree. +<li> Port their applications to multiple platforms with a simple +recompilation. +<li> Internationalize their applications. +<li> Provide their applications with native look and feel. +<li> Have their applications run at native speed. +</ul> +<p> <hr width="30%"> +<h3> What is Trolltech? +</h3> +<a name="1-2"></a><p> Trolltech is an international software company with +headquarters in Oslo, the capital of Norway, and with offices +in Brisbane, Australia, and Redwood City, California. Our +flagship product is Qt, the multi-platform C++ GUI toolkit. +<p> Trolltech ASA was founded in 1994, although, the core team of designers +started Qt's development in 1992. +<p> More details can be found at <a href="troll.html">Trolltech</a>. +<p> <hr width="30%"> +<h3> How can I evaluate Qt? +</h3> +<a name="1-3"></a><p> We offer 30 day evaluation versions of Qt on all our supported platforms. +Further details can be found here: <a href="http://www.trolltech.com/evaluate.html">http://www.trolltech.com/evaluate.html</a>. +<p> <hr width="30%"> +<h3> What does Qt cost? +</h3> +<a name="1-4"></a><p> This depends on your number of developers, on how many +different platforms you target, and on the edition of Qt you +choose. Currently we offer two different editions (Enterprise +Edition and Professional Edition) on four different +platforms (Microsoft Window, Unix/X11, Macintosh and Linux/embedded). +<p> We also offer discounts for academic and research institutions. +<p> Details on pricing can be found here: +<a href="http://www.trolltech.com/pricing.html">http://www.trolltech.com/pricing.html</a>. +<p> <hr width="30%"> +<h3> How can I buy Qt? +</h3> +<a name="1-5"></a><p> To purchase, please visit the <a +href="https://webshop.trolltech.com/cgi-bin/index.cgi">Trolltech +webshop</a>. In the webshop, you can generate a Purchase Order, order +a Quote, or purchase directly using a credit card. +<p> For further information and assistance, please contact Trolltech sales: +<p> Email: <a href="mailto:sales@trolltech.com">sales@trolltech.com</a> +Phone, US office (for North America): <strong>(+1) 650-813-1676</strong> +Phone, Norway office (for others): <strong>+47 2160 4800</strong> +<p> <hr width="30%"> +<h3> What kind of technical support is available for Qt? +</h3> +<a name="1-6"></a><p> Trolltech offers email support to commercial licensees. The first year +of Trolltech's Support and Maintenance Service is included with the +purchase of Qt Professional and Qt Enterprise Edition licenses. +Licenses can be kept up-to-date and fully supported by buying +the Support and Maintenance Service for the licenses held in each +subsequent year. +<p> For further information see here: +<a href="http://www.trolltech.com/support/">http://www.trolltech.com/support/</a>. +<p> <hr width="30%"> +<h3> Who provides training for Qt? +</h3> +<a name="1-7"></a><p> A number of companies provide Qt training, in Asia, Europe and the US. +Trolltech has agreements with a number of official training +partners, who offer Trolltech approved courses. In addition +there are a number of independently developed courses run by third +parties. You can find more information about the partners and the +courses here: <a href="http://www.trolltech.com/training/">http://www.trolltech.com/training/</a>. +<p> <hr width="30%"> +<h3> Who provides consultancy for Qt? +</h3> +<a name="1-8"></a><p> A number of companies provide consultancy services for Qt and +Qtopia. You can find a partial list here: +<a href="http://www.trolltech.com/company/servicepartners.html">http://www.trolltech.com/company/servicepartners.html</a>. +<p> <hr width="30%"> +<h3> Are there any books about Qt programming? +</h3> +<a name="1-9"></a><p> Yes, there are quite a few books on Qt, most of them +available from amazon.com. You can find a partial list at +<a href="http://www.trolltech.com/developer/books.html">http://www.trolltech.com/developer/books.html</a>. +<p> The official Qt book is +<a href="http://www.amazon.com/exec/obidos/ASIN/0131240722/trolltech/">C++ GUI Programming with Qt 3</a>. +<p> <hr width="30%"> +<h3> What is the Open Source Edition? +</h3> +<a name="1-10"></a><p> The Qt Open Source Edition is our non-commercial versions of +Qt. You can use this edition to create and run free +software, i.e. software that is licensed under the GNU GPL or +a similarly recognized open source license. +<p> Qt Open Source edition is available for Unix/X11, Macintosh and +Linux/embedded. +<p> <hr width="30%"> +<h3> What is the idea behind having a free version of Qt? +</h3> +<a name="1-11"></a><p> With the Open Source Edition, Trolltech has found a way to support +the free software concept. Part of our commitment is to enable +those who contribute to the free software pool to do so +without paying license fees. +<p> <hr width="30%"> +<h3> Is there a low-cost version of Qt for writing shareware? +</h3> +<a name="1-12"></a><p> No, but Qt's commercial licenses permit you to write and sell +shareware written with Qt. +<p> <hr> +<h2> Questions about Qt's Users +</h2> +<a name="2"></a><p> <hr width="30%"> +<h3> How many developers use Qt? +</h3> +<a name="2-1"></a><p> We don't know! We can count our many thousands of commercial +licensees, but the number of free software developers +using Qt can only be guessed based on download figures, book +sales, the number of open source Qt applications available on +the web, Universities teaching with Qt, and other factors. A +conservative estimate would put the figure at around 100,000 to +150,000 developers world-wide. +<p> <hr width="30%"> +<h3> Which major corporations use Qt? +</h3> +<a name="2-2"></a><p> See our list of reference customers at +<a href="http://www.trolltech.com/company/customers.html">http://www.trolltech.com/company/customers.html</a>. Note that many +commercial customers do not disclose their use of Qt because they see +Qt as a competitive advantage. +<p> <hr width="30%"> +<h3> Are there any well-known applications that use Qt? +</h3> +<a name="2-3"></a><p> There are many, e.g. Adobe Photoshop Album from Abobe +Corporation and the KDE desktop. A partial list can be found at +<a href="http://www.trolltech.com/products/qt/apps-using-qt.html">http://www.trolltech.com/products/qt/apps-using-qt.html</a> +<p> <hr> +<h2> Questions about Developing Applications with Qt +</h2> +<a name="3"></a><p> <hr width="30%"> +<h3> Is there a mailing list for Qt? +</h3> +<a name="3-1"></a><p> Trolltech operates several mailing lists for Qt users including +<tt>qt-announce</tt>, <tt>qt-interest</tt> and <tt>snapshot-users</tt>. +<p> See <a href="http://lists.trolltech.com">Mailing lists</a>. +<p> <hr width="30%"> +<h3> Is Qt's documentation available online? +</h3> +<a name="3-2"></a><p> Yes, at <a href="http://doc.trolltech.com">http://doc.trolltech.com</a>. +<p> <hr width="30%"> +<h3> Is there a technical newsletter for Qt? +</h3> +<a name="3-3"></a><p> Yes, <a href="http://doc.trolltech.com/qq/index.html">Qt +Quarterly</a>. It is a paper-based newsletter exclusively +available to Qt licensees. +<p> As a courtesy and convenience to all our users, a selection of +articles is also published online about one month after publication. +<p> <hr width="30%"> +<h3> I think I have found a bug in Qt. Where can I report it? +</h3> +<a name="3-4"></a><p> Bugs should be reported to <a href="mailto:qt-bugs@trolltech.com">qt-bugs@trolltech.com</a>. But <em>please</em> read (the very short) +<a href="bughowto.html">How to Report a Bug</a> page <em>first</em>. +<p> <hr> +<h2> Questions about Professional Licensing +</h2> +<a name="4"></a><p> <hr width="30%"> +<h3> We have purchased a license, but the developer is leaving the company +project. Can we transfer the license to another developer? +</h3> +<a name="4-1"></a><p> Yes. Qt licences are for the individual use of named developers. If +the developer associated with a licence leaves the organization, or +moves on to another project that does not require a Qt license, +another developer can take over the licence. You can change the name +of the developer using a licence at any time, but after a change you +must wait at least six (6) months before changing again. +<p> <hr width="30%"> +<h3> Can I purchase floating licenses for Qt? +</h3> +<a name="4-2"></a><p> No, we do not offer floating licenses. +<p> The reason is this: Floating licenses are based on the concept +of defining a maximum number of concurrent users. For example, +for a word processor, this means the maximum number of +instances of that application that can be running at any +time. However, for a library product like Qt, there is no main +application that is always running when the product is being +used. Hence, it is not possible to count the number of +concurrent users, and therefore floating licenses do not +make sense. +<p> +<p> <hr width="30%"> +<h3> Can we use the Open Source Edition while developing our non-free +application and then purchase commercial licenses when we start to +sell it? +</h3> +<a name="4-3"></a><p> No: our commercial license agreements only apply to software +that was developed with Qt under the agreement. They do not +apply to code that was developed with the Qt Open Source Edition +prior to the agreement. Any software developed with Qt +without a commercial license agreement must be released as +free/open source software. +<p> <hr> +<h2> Questions about Open Source Software Licensing +</h2> +<a name="5"></a><p> <hr width="30%"> +<h3> I just want to run KDE and other Qt-based software on my +machine. Can I do that with the Open Source Edition? +</h3> +<a name="5-1"></a><p> Yes. You may use the Qt Open Source Edition for running applications, +both at home and at work, without restrictions. +<p> <hr width="30%"> +<h3> I want to put Qt, and applications that use it, on a CD-ROM or on +a web site. Can I do that with the Open Source Edition? +</h3> +<a name="5-2"></a><p> Yes. You may copy and redistribute the Qt Open Source Edition, both +at home and at work, without restrictions. +<p> <hr width="30%"> +<h3> Can I make software with the Qt Open Source Edition and release it under +the GNU GPL, BSD, or Artistic license? +</h3> +<a name="5-3"></a><p> Yes. The GNU GPL, GPL-compatible licenses, or any other +approved open source license will do. The FSF.org and +OpenSource.org web sites list approved software licenses. +<p> <hr width="30%"> +<h3> I don't want to give away my source code. What do I do? +</h3> +<a name="5-4"></a><p> You need to buy a commercial Qt license. +<p> <hr width="30%"> +<h3> Is software based on the Qt Open Source Edition really free? Does it +carry any Trolltech-specific license restrictions? +</h3> +<a name="5-5"></a><p> Yes, it really is free. This is because the Qt Open Source Edition +uses the GNU GPL, which forbids the imposition of any license +restrictions on software based on the Open Source Edition that would +make it non-free. And no, there are no Trolltech-specific +license restrictions on software produced using the Open Source +Edition. +<p> <hr width="30%"> +<h3> What if Trolltech stops releasing Open Source Editions of Qt? +</h3> +<a name="5-6"></a><p> We have absolutely no intention of doing that. Together with +the K Desktop Environment project, we have set up the KDE Free +Qt Foundation (see +<a href="http://www.kde.org/whatiskde/kdefreeqtfoundation.php">http://www.kde.org/whatiskde/kdefreeqtfoundation.php</a>) to +legally guarantee the availability of Qt for free software +development now and forever - even if circumstances beyound +our control prevent us from producing new free editions. +<p> <hr width="30%"> +<h3> Using the Open Source Edition, can I make non-free software for internal +use in my company/organization? +</h3> +<a name="5-7"></a><p> No. Software developed with the Open Source Edition is always free +software, i.e. it can only be distributed under a free +software license. In particular, all the source code for all +the modules your software is based on, regardless of whether +they have been written by you or by others, must be free +software. This is part of our commitment to the free software +community, and enables those who contribute to the free +software pool to do so without paying license fees. +<p> Although it is possible to write free software for internal +use, it is difficult to ensure that such software is used and +distributed legally. For example, if your free software +requires any modules that impose conditions on you that +contradict the conditions of the GNU GPL, including, but not +limited to, software patents, commercial license agreements, +copyrighted interface definitions or any sort of +non-disclosure agreement, then you cannot distribute it at +all; hence it cannot be given to consultants, employees for +their personal computers, subsidiaries, other divisions, or +even to new owners. +<p> Consequently we recommend using commercial licenses for all +internal software development. +<p> <hr width="30%"> +<h3> Is Qt Open Source Edition really free software in the GNU meaning of the +word? +</h3> +<a name="5-8"></a><p> Yes - it is free software both as in "no cost" and as in +"free speech". Even more, it is actually available under the +terms of the GNU GPL. This means you can link GPL'ed software +to it, and you can take code from Qt and put it into other +GPL'ed software. +<p> <hr width="30%"> +<h3> If the Open Source Edition is GNU GPL, aren't there license conflicts +with incompatible open source licenses? How come people can even +run commercial software like the Opera web browser with it? +</h3> +<a name="5-9"></a><p> If the Open Source Edition was licensed purely under the GNU GPL, +there would be problems. However, as long as Qt-based +software is either open source or was developed under a +commercial license agreement with Trolltech, we grant +permission to compile, link and run those programs with the +Open Source Edition. This is written down in our second free software +license, the QPL. +<p> <hr width="30%"> +<h3> Doesn't such an en extra license in addition to the GNU GPL +violate the terms of the GPL or at least make the whole package +GPL-incompatible? +</h3> +<a name="5-10"></a><p> No, because those extra license terms give you rights in +addition to those of the GNU GPL, including the right to +remove those extra terms. +<p> <hr width="30%"> +<h3> Why is Qt Open Source Edition not distributed under the GNU Lesser +General Public License (LGPL)? +</h3> +<a name="5-11"></a><p> The LGPL is designed to "permit developers of non-free +programs to use free libraries" (quote from the LGPL). In +other words, if Qt Open Source Edition were LGPL'd, companies would +not have to purchase our commercial editions in order to make +commercial/proprietary software, they could just use the Open Source +Edition, free of charge. That would mean Trolltech would not +get the revenue necessary for improving and extending Qt. +<p> Note also that the Free Software Foundation discourages the +use of the LGPL. +<p> <hr> +<h2> Questions about other programming languages +</h2> +<a name="6"></a><p> <hr width="30%"> +<h3> Are there bindings to languages other than C++? +</h3> +<a name="6-1"></a><p> Yes there are, e.g. bindings to Perl (PerlQt) and Python +(PyQt). These bindings were written by the open source +community and are not supported by Trolltech. +<p> <hr width="30%"> +<h3> Can I develop commercial applications with PerlQt or PyQt or other +Qt wrappers? +</h3> +<a name="6-2"></a><p> Yes, if you have purchased a commercial license. The licensing +conditions are the same whether you use the Qt API directly in +C++, or you use it through some API wrapper in another +programming language. All developers that write code +containing calls to the Qt API (directly or through a wrapper) +need Qt licenses. +<p> +<!-- eof --> +<p><address><hr><div align=center> +<table width=100% cellspacing=0 border=0><tr> +<td>Copyright © 2007 +<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a> +<td align=right><div align=right>Qt 3.3.8</div> +</table></div></address></body> +</html> |