LAB Documentation

As applied to the Qt Free Edition Version 2.0

Note:

This is not a legal document. For the exact interpretation of the license you must read it and understand it. This page is simply meant to explain the license in an easy to understand and informal way.

The intent of this license is to establish freedom to share and change the software regulated by this license under the open source model.

This license applies to any software containing a notice placed by the copyright holder saying that it may be distributed under the terms of the Q Public License version 1.0. Such software is herein referred to as the Software. This license covers modification and distribution of the Software, use of third-party application programs based on the Software, and development of free software which uses the Software.

Granted Rights

You are granted the non-exclusive rights set forth in this license provided you agree to and comply with any and all conditions in this license. Whole or partial distribution of the Software, or software items that link with the Software, in any form signifies acceptance of this license.

This is to ensure that everyone follows the rules. If you do not accept this license you are not given the right to distribute the software, to make modifications to it nor develop anything with it.

You may copy and distribute the Software in unmodified form provided that the entire package, including - but not restricted to - copyright, trademark notices and disclaimers, as released by the initial developer of the Software, is distributed.

Attention:: Distribute the software, i.e. Qt, to anyone you like, as long as you include everything in the original distribution. In order to preserve the integrity of the unmodified version, modifications are restricted to being separated in some way from the original Qt source code.

You may make modifications to the Software and distribute your modifications, in a form that is separate from the Software, such as patches. The following restrictions apply to modifications:

You can make and distribute changes, the preferred form being patches.
Attention:
You cannot just change the code and redistribute it, as this would not be separate - people would not know what part of the software is Qt and what part is the changes you made.

The easiest way to deal with this is to use a version management system such as CVS - you will find that it is in fact much easier to distribute patches than to try to deal with entire files. With patches, you can easily incorporate changes made by others into your copy of Qt.
You may also distribute a modified binary version if you include the patch (see 4).

Patches should include an accurate description of the modification, the date of the modification, and the author of the modification.
A typical patch is shown below.

Copyright (C) 1998 Harald Acker
This patch may be distributed under the terms of the Q
Public License, version 1.0 or later.
This patch is for Qt 2.42.  It fixes the bug where Foo
objects move right when they should move left.
-=- qfoo.cpp        1998/09/15 10:44:25     2.18.2.3
+++ qfoo.cpp        1998/11/20 12:28:12
@@ -157,2 +157,2 @@
        // Move to the left
+  x += 1;
-  x -= 1;

Any technique is acceptable for keeping changes separate - generally, you would have to mark changes very clearly for them to be separate. We don't want to hard-code the idea that the form must be patches.

a. Modifications must not alter or remove any copyright notices in the Software.
Attention:
This doesn't really need to be stated, since to do so would be fraudulent.
b. When modifications to the Software are released under this license, a non-exclusive royalty-free right is granted to the initial developer of the Software to distribute your modification in future versions of the Software provided such versions remain available under these terms in addition to any other license(s) of the initial developer.
Attention:
You may license your patch any way you see fit, but note that when distributed in a binary form of Qt, it must be licensed under the QPL - this is explained in section 4.

This clause makes it possible for Trolltech to include patches in new versions of Qt. It also means that the same patches can be included in the Qt Professional Edition, but Trolltech are in turn required to ensure that those changes are in both versions.

You may distribute machine-executable forms of the Software or machine-executable forms of modified versions of the Software, provided that you meet these restrictions:

You may distribute binaries.

a. You must include this license document in the distribution.
Attention:
You must tell the recipients about their rights.
b. You must ensure that all recipients of the machine-executable forms are also able to receive the complete machine-readable source code to the distributed Software, including all modifications, without any charge beyond the costs of data transfer, and place prominent notices in the distribution explaining this.
Attention:
The easiest way to achieve this is to have the source code accompany the binary version. For FTP distribution, it should be just as accessible. For CD-ROM distribution, it should be on an accompanying CD. The basic rule here is "binary follows source".
c. You must ensure that all modifications included in the machine-executable forms are available under the terms of this license.
Attention:
Most patches contain quoted Qt code, plus work of your own. You may license your patch any way you see fit, but when distributed in a binary form of Qt, it must be licensed under the QPL. Be careful if taking code from other sources to include in Qt - that other software may not allow such copying.

Why? Without this restriction, nothing would prevent modified versions of Qt, licensed under non-free licensing.

You may use the original or modified versions of the Software to compile, link and run application programs legally developed by you or by others.

Attention:: If you have a program written for the software, go ahead and use it. This allows you to use software created under either the Qt Free Edition license or the Qt Professional Edition license with the one library version.

You may develop application programs, reusable components and other software items that link with the original or modified versions of the Software. These items, when distributed, are subject to the following requirements:

Attention:: This is a license designed for libraries, therefore we must also talk about application programs or other libraries (components) that are linked with the software, as these include portions of Qt when in binary form. Of course, given the term "link", there is no differentiation between static and dynamic linking.
In essence this clause says that you may develop programs that link with Qt provided that you develop Open Source software.

a. You must ensure that all recipients of machine-executable forms of these items are also able to receive and use the complete machine-readable source code to the items without any charge beyond the costs of data transfer.
Attention:
Like 4b., "source follows binary". You are free to charge for binaries, however you must also supply the source code. Note that "all recipients" includes recipients that you do not directly transfer copies to. The easiest way to achieve this is to allow (or insist) that all recipients can further distribute the source.
b. You must explicitly license all recipients of your items to use and re-distribute original and modified versions of the items in both machine-executable and source code forms. The recipients must be able to do so without any charges whatsoever, and they must be able to re-distribute to anyone they choose.
Attention:
This ensures that all recipients have the same rights, no matter how or from whom they received the software. The easiest way to provide this explicit license is to allow recipients to grant the same license to others.
If the recipients of your software wishes to do so they may re-distribute your software without anyone having to pay money either to them or to you.
c. If the items are not available to the general public, and the initial developer of the Software requests a copy of the items, then you must supply one.
Attention:
This is to avoid problems with companies that try to hide the source. If we get to know about it we want to be able to get hold of the code even if we are not users. In this way, if somebody tries to cheat and we get to know we can release the code to the public.

Q Public License (Annotation)

Granted Rights

Limitations of Liability

No Warranty

Choice of Law