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Package license guidelines

All packages distributed in OpenAlea must have a free/Open Source license. This is a necessity for the collaborative developpement and to share software. The restriction involved by non free license are incompatible with the OpenAlea goals.

We list in this document different OpenSource licenses which are compatible for OpenAlea packages.

GNU GPL/LGPL licenses


GNU General Public License is a widely used free software license, originally written by Richard Stallman for the GNU project. The latest version of the license, version 2, was released in 1991.

The GPL grants the recipients of a computer program the following rights:

  • the right to run the program, for any desired purpose.
  • the right to study how the program works, and modify it. (Access to the source code is a precondition for this)
  • the right to redistribute copies.
  • the right to improve the program, and release the improvements to the public. (Access to the source code is a precondition for this)

In contrast, the end-user licenses (EULA) that come with proprietary software generally only grants the end-user the right to copy the software onto a limited number of computers. The terms and conditions of such license agreements may even attempt to restrict activities normally permitted by copyright laws, such as reverse engineering.

The primary difference between the GPL and more “permissive” free software licenses is that the GPL seeks to ensure that the above points are preserved in copies and in derivative works. It does this using a legal mechanism which requires derivative works of GPL-licensed programs to also be licensed under the GPL. In contrast, BSD-style licenses allow for derivative works to be redistributed as proprietary software.

For more informations, visit http://www.gnu.org/licenses/gpl.html. Text from Wikipedia


The GNU Lesser General Public License (formerly the GNU Library General Public License) is a free software license published by the Free Software Foundation. It was designed as a compromise between the strong-copyleft GNU General Public License and simple permissive licenses such as the BSD licenses and the MIT License. The GNU Lesser General Public License was written in 1991 (and updated in 1999) by Richard Stallman, with legal advice from Eben Moglen

The main difference between the GPL and the LGPL is that the latter can be linked to (in the case of a library, 'used by') a non-(L)GPLed program, which may be free software or proprietary software [1]. This non-(L)GPLed program can then be distributed under any chosen terms, provided the terms allow “modification for the customer's own use and reverse engineering for debugging such modifications.”

The LGPL places copyleft restrictions on the program itself but does not apply these restrictions to other software that merely links with the program.

Text from Wikipedia

For more informations, visit http://www.gnu.org/copyleft/lesser.html.

CeCILL licenses

CEA, CNRS and INRIA released CeCILL in july 2004. CeCILL is a license defining the principles of use and dissemination of Free Software in conformance with French law, following the principles of the GNU GPL. This license is meant to be used by companies, research institutions and all organisations willing to release software under a GPL-like license while ensuring a standard level of legal safety. CeCILL is also perfectly suited to international projects.

After CeCILL, CEA, CNRS and INRIA are releasing two new Free Software licenses, conforming to French law, CeCILL-B and CeCILL-C. These two licenses offer new models for developpers to control the reuse of their software. These two licenses provide the same level of legal safety as CeCILL does. Authorizing the reuse of components under CeCILL-B or CeCILL-C in a software that can be distributed under any license, they thus encourage a wider diffusion of these components.

CeCILL-B follows the principle of the popular BSD license and its variants (Apache, X11 or W3C among others). In exchange for strong citation obligations (in all software incorporating a program covered by CeCILL-B and also through a Web site), the author authorizes the reuse of its software without any other constraints.

CeCILL-C is well suited to libraries and more generally software components. Anyone distributing an application which includes components under the CeCILL-C license must mention this fact and make any changes to the source code of these components available to the community under CECILL-C while being free to choose the licence of its application. CeCILL-C licence follows the principles of the GNU LGPL.

from www.cecill.info

For more information, visit the CeCill website

Multiple licenses

It is possible to distribute a software/package under different licenses. For instance, Trolltech distribute QT

  • either under the GPL license, which is free and OpenSource, but force the derivated works to be also under the GPL.
  • or under a commercial license, which is non free, but which give you the right to distribute your derivated application under the license terms of your choice.

How to release my program under a license

If you are the author of a program you want to distribute under one of the previous license, we recommend to follow the following steps :

  1. determine who are the owners of the relevant rights on the program
  2. make the inventory of the pieces of code and libraries that you use. To be able to distribute your software under a given license, it is necessary that the licenses of all external code are compatible with the chosen license.
  3. choose a compatible licence with all the constraints
  4. add the licence header in each source file, in the documentation and on the website.
  5. distribute the license term with your software in a file named license.txt.
  6. you can also set up a mechanism to explicity verify that the user read and accept the license every time it is possible and not too inconvenient.


documentation/guidelines/license_guidelines.txt · Last modified: 2006/11/10 14:56 (external edit)   Back to top
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