64 van 71
GNU General Public Licence
Version 2, June 1991
Copyright (C) 1989,
1991 Free Software Foundation, Inc.
51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
Preamble
The licenses for most software are designed to take away your freedom
to share and change it. By contrast, the GNU General Public License is in-
tended to guarantee your freedom to share and change free software-
-to make sure the software is free for all its users. This General Public Li-
cense applies to most of the Free Software Foundation‘s software and to
any other program whose authors commit to using it. (Some other Free
Software Foundation software is covered by the GNU Lesser General Pu-
blic License instead.) You can apply it to your programs, too.
When we speak of free software, we are referring to freedom, not pri-
ce. Our General Public Licenses are designed to make sure that you have
the freedom to distribute copies of free software (and charge for this
service if you wish), that you receive source code or can get it if you want
it, that you can change the software or use pieces of it in new free pro-
grams; and that you know you can do these things.
To protect your rights, we need to make restrictions that forbid anyone
to deny you these rights or to ask you to surrender the rights. These res-
trictions translate to certain responsibilities for you if you distribute co-
pies of the software, or if you modify it.
For example, if you distribute copies of such a program, whether gratis
or for a fee, you must give the recipients all the rights that you have. You
must make sure that they, too, receive or can get the source code. And
you must show them these terms so they know their rights.
We protect your rights with two steps: (1) copyright the software, and (2)
offer you this license which gives you legal permission to copy, distribu-
te and/or modify the software.
Also, for each author‘s protection and ours, we want to make certain that
everyone understands that there is no warranty for this free software. If
