Q Public License
The Q Public License is a free software license from the Trolltech company and became known through the Qt product .
The license is intended to grant the freedom to exchange the software in the sense of open source , similar to the well-known GNU General Public License (GPL). It is certified by the Open Source Initiative , which gives you more certainty that QPL-licensed software is open source.
The QPL is generally not compatible with the GPL, as changes to QPL-licensed software can only be distributed in the form of patches or similarly clearly marked. The GPL therefore theoretically prohibits the linking of QPL software with GPL software, but some rights holders such as the Free Software Foundation grant special permits for this.
right
Software published under the QPL can be copied and redistributed in an unchanged form as long as the package is left intact - i. H. Copyright notices, trademarks and disclaimers of liability must be given as specified by the manufacturer. This ensures the integrity of the original version.
The software may be changed and these changes may also be distributed, but only in a form that is separate from the original code, e.g. B. Patches . However, other forms are not prohibited by the license, you can also clearly mark your changes in other ways. Copyright notices are again excluded from changes. This underlines the strict separation of original and change.
If the developer publishes the source code of his changes to QPL-licensed software himself under the QPL (which he does not have to), the author of the original version receives the right to incorporate these changes in a future version as long as it is again the QPL for this future version elects. This means that the developer of the original can use the work of other developers, which was made possible by the openness of the source code, for himself, but only if he releases it again to the developer community.
When publishing the changes in binary version, the developer must consider a few points. On the one hand, he must approve the changes under the QPL license; on the other hand, he must ensure that the users are clear about their rights (by enclosing the license text) and have access to the source code. To do this, he must not charge more than the cost of the transmission, and he must clearly note the availability of the code in its changes. This is very similar to the GNU General Public License , which also ensures that the source code is always available for binary code. This passage also prevents changes to QPL-licensed software from simply being placed under a different, possibly chargeable license.
Like most free software licenses , this one also grants the right to full use of the original or modified version together with other software and individually.
For the connection with other programs ( "links" ), the QPL stipulates that the linked software must also be free software. In this case, this means that the users of the linked software must receive the source code at most for the price of the transfer and changes to the linked software are permitted, again with the permission of the transfer in binary and source code form to any person. If the linked programs or the source code are not available to the public, the developer of the original software can request that he receive a copy of the source code. In this way, the code can be published after all, since everyone who is in possession of a linked program is allowed to pass it on.
Disclaimer of liability
The QPL completely excludes the liability of the developer for damages in any case, even if he was informed about defects.
In addition, no guarantee is given, the software and license are given "as is" .
The QPL's place of jurisdiction is Norway ; the Oslo City Court is specified as the court . So far, however, the license has never had to be defended in court.
history
The Q Public License arose from the competition of the two Linux - desktop environments K Desktop Environment and Gnome .
KDE uses Qt as a library for graphing. Until 1998, Qt was a purely proprietary product, which led to the creation of the GNOME desktop in 1998 in order not to be dependent on a company.
But with version 2.0 Trolltech changed the license of Qt at the urging of the Free Software Foundation - Qt was published under the QPL. This ensured free development. There was an additional license for commercial products. This license change made it possible for most Linux distributions to include the K Desktop Environment in their package list.
In April 1998 the responsibility for the QPL and thus the right to change it was transferred to the KDE Free Qt Foundation . This ensured the freedom of Qt, because the foundation can, should Trolltech cease to exist as a company or stop the development of Qt, place the last version under the BSD license .
With version 4.5, Qt was placed under the less restrictive LGPL in March 2009 .
Popular projects under the QPL
- Qt - library u. A. to create graphical user interfaces for different operating systems
- Cervisia - CVS interface for KDE
literature
- Volker Grassmuck: Free Software, ISBN 3-89331-569-1 (pp. 270–302, online )
