I have heard the opinion that the qt licensing option can be interpeted as allowing the user to decide on a perapplication basis which license they will use, but i cant really buy that. As someone who works for a company that owns qt commercial for unix, id like to offer my point of view. Development platforms and restrictions this certificate entitles a single developer to use the software for development on the following platforms. The legal department will tell you buy our commercial license, its the only option. Qt for application development is also available under gpl and lgplv3 open source licenses. The free software foundation may publish revised andor new versions.
Can i use an lgpllicenced library in my commercial app. Metallicow licensing pyside has been published as a response to the lack of suitably licensed qt bindings for python. The qt development tools and related applications like the qt creator ide will be released under the gplv3 as well as a commercial license. But the lack of an lgpl option is what arguably lead to the rise of gnomegtk when that project started in 1997, because its the lgpl that allows organizations to write closedsource proprietary software without paying a. Why is qt not distributed under the gnu library general public license lgpl. Thats not true of course, its lgpl licensed and so can be used for commercial software as long as the license obligations are adherred to.
Qts commercial license is for when you wish to modify qts source code, and not release the changes you have made to the public. Unless you dont violate requirements of lgpl license, you dont need to go for commercial. The qt company ltd, valimotie 21, 00380 helsinki, finland. Also, theres nothing preventing you from selling an open source app on the microsoft app marketplace. Gnu lesser general public license version 3 open source. The commercial licence gives you the full freedom of releasing your product including you can hide the fact you use qt library in your product.
It was not published by the free software foundation, and does not legally state the distribution terms for documents that uses the gnu lgplonly the original english text of the gnu lgpl does that. If you want to borrow any code released as gpl for use in your own source code, any of your own code that the gpl is mixed with will also. It fails the debian free software guidelines, used by several linux distributions, though it qualifies for the free software foundations free software definition. If you already started a project based on qt you need to be quick if. As qt for android uses the lgpl version of qt, and its perfectly possible and also recommended and supported to dynamically link in the qt libraries when creating an app there are no problems for app developers using qt for android. With the commercial license you also have access to the official qt support and close strategic relationship with the qt company to make sure your development goals are met. Is the version in the downloads section a lgpl version. Using the digia qt framework lgpl for commercial applications. Even modules like the virtual keyboard, the software renderer for qml without opengl and the unittest integration into qtcreator will become available under gpl. Read the legal definition ofand proprietary, then go consult a lawyer. Qt licensed under the gnu lesser general public license lgpl version 3 is. All other trademarks are property of their respective owners.
In such case, this license incorporates the limitation as if written in the body of this license. It is very dissapointing however to see absolutely no help from people who work in qt on the lgpl subject. As a special exception to the gnu lesser general public license version 2. The aim of this article is to clear up some of that uncertainty. Qt for application development is duallicensed under commercial and open source licenses. The older nontouchscreen model was apparently under 4. You can also make commercial apps using qt for free with the lgpl license.
See how to choose a license for your own work for general recommendations about choosing a license for your work the gnu project has two principal licenses to use for libraries. The qt libraries are available under the gpl or lgpl license. Does still qt support lgpl license for future updates or is it commercial only now on. Gnu lesser general public license version 3, 29 june 2007 copyright c 2007 free software foundation, inc. Qt licensed under our commercial license agreement is appropriate for development of proprietarycommercial software where you do not want. The desktop app i sell uses qt, against the lgpl license. The app developers can develop closed source code and publish the app. In compliance with lgpl, this document collects the relevant information about downloading, installing, and building the. The mobile phone giant is expected today to announce that qt 4. Trolltech is perhaps the most successful free software company around and they have no shortage of commercial third party software companies that choose qt. The free software foundation may publish revised andor new versions of the gnu lesser general public license from time to time. The lgpl is designed to permit developers of nonfree programs to use free libraries quote from the lgpl.
Lgpl which qt is released allows commercialclosed source applications as long as you do not modify the qt libraries or if you do making them available to the public. You can use only those parts of qt that are under the lgpl and have no concerns about opensource. Both licences allow the use of the library for commercial purpose. Since your corporate application is for inhouse use only, you or more accurately, your company could license qt under the gpl for free. The open source archive for the new model includes the lgpld qt 4. In addition to the all os license terms supplied with the commercial release of qt 4.
You can get a commercial license which allows you to do everything with qt with no concerns about opensource. This license covers distribution of the software, use of thirdparty application programs based on the. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. Documentation contributions included herein are the s of their respective owners. Revised versions of the gnu lesser general public license.
Qt is available under lgplv3 so that half of the problem is solved. The gpl makes sense for tools, as it ensures that anyone distributing a modified version gives the changes back to the community, but doesnt prevent using the tools to create nonfree software. In other words, if qt were lgpld, companies would not have to buy the professional edition in order to make commercial nonfree software, they could just. Qt licensed under the gnu lesser general public license lgpl version 3 is appropriate for the development of qt applications provided you can comply with the terms and conditions of the gnu lgpl version 3 or gnu gpl version 3. Qts lgpl license relates to qt and qt only, so you can package your code and license it however you like, but unless you plan on buying a qt commercial license, you have to dynamically link to qt. Qt licensed under commercial licenses is appropriate for development of. As long as you meet the requirements that gpl or lgpl impose on you, you have nothing to worry about. Besides, it doesnt matter since kdelibs is lgpld, and therefore cant be linked with gpld qtx11. Python examples of modern gui python programms grokbase. The qt company gratefully acknowledges these and other contributions to qt. Do i have to buy a qt commercial license for developing an. Lgpl allows you to have a binary application, as long as it is dynamically in the sense of at runtime linked. This is at least the stated goal of the qt company. Highend components and thermal solutions, made possible by our years of industry experience, provide better.
Why you shouldnt use the lesser gpl for your next library. Qt started off with a commercial license in 1995, adding gpl in 2000. The gnu lesser general public license lgpl is a freesoftware license published by the free software foundation fsf. This license applies to any software containing a notice placed by the holder saying that it may be distributed under the terms of the qt noncommercial license version 1. Moving to the issue of source publication, that is specifically, deliberately removed under lgpl lesser gpl, providing certain conditions are met. Qt contains also thirdparty code that is licensed under specific opensource licenses from the original authors. Most likely all developers were instructed to answer ianal, please contact our legal department. The lgpl license allows an application that references the binaries to remain closedsource. For opensource licensed qt, some specific parts modules are not available under the gnu lgpl version 3, but under the gnu general public license gpl instead. The commercial qt license gives you the full rights to create and. The third alternative is to go with the gpl license, which will require your product to meet the gpl2 or gpl3 terms. This is an unofficial translation of the lgpl free documentation license into chinese.
As i understand, you can buy a commercial license from qt and get commercial support, patches etc like we do in our company. The commercial qt license gives you the full rights to create and distribute software on your own terms without any open source license obligations. Since qt is being used under lgpl, they dont have to release code that calls it. But if you use some 3rdparty libraries which are not lgpl and instead gpl, then again there are some additional things you might need to do.
On the qt website you can find obligations of the lgpl. Qt to be available for free under lgpl successful software. The q public license qpl is a noncopyleft license, created by trolltech for its free edition of the qt. The qm modeling tool uses the qt toolkit under the terms of the gnu lesser general public license v. Only users with topic management privileges can see it. So qtproject develops the open source version while digia develops the commercial one.
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