User`s manual

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109
Appendix
The GNU General Public License (GPL)
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 intended to guarantee your freedom to share and change free software--to make sure the software is free for all its users. This
General Public License 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 Public License instead.) You can apply it
to your programs, too.
When we speak of free software, we are referring to freedom, not price. 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 programs; 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 restrictions translate to certain responsibilities for you if you distribute copies 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) oer you this license which gives you legal permission to copy,
distribute 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 the software is modied by someone else and passed on, we want its recipients to know that what they have is not the
original, so that any problems introduced by others will not reect on the original authors’ reputations.
Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program
will individually obtain patent licenses, in eect making the program proprietary. To prevent this, we have made it clear that any patent
must be licensed for everyone’s free use or not licensed at all.
The precise terms and conditions for copying, distribution and modication follow.
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be
distributed under the terms of this General Public License. The “Program”, below, refers to any such program or work, and a “work
based on the Program” means either the Program or any derivative work under copyright law: that is to say, a work containing the
Program or a portion of it, either verbatim or with modications and/or translated into another language. (Hereinafter, translation is
included without limitation in the term “modication”.) Each licensee is addressed as “you”.
Activities other than copying, distribution and modication are not covered by this License; they are outside its scope. The act of
running the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on
the Program (independent of having been made by running the Program). Whether that is true depends on what the Program does.
1. You may copy and distribute verbatim copies of the Program’s source code as you receive it, in any medium, provided that you
conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all
the notices that refer to this License and to the absence of any warranty; and give any other recipients of the Program a copy of this
License along with the Program.
You may charge a fee for the physical act of transferring a copy, and you may at your option oer warranty protection in exchange
for a fee.
2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and
distribute such modications or work under the terms of Section 1 above, provided that you also meet all of these conditions:
a) You must cause the modied les to carry prominent notices stating that you changed the les and the date of any change.
b) You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be
licensed as a whole at no charge to all third parties under the terms of this License.
c) If the modied program normally reads commands interactively when run, you must cause it, when started running for such interactive use in the
most ordinary way, to print or display an announcement including an appropriate copyright notice and a notice that there is no warranty (or else,
saying that you provide a warranty) and that users may redistribute the program under these conditions, and telling the user how to view a copy of
this License. (Exception: if the Program itself is interactive but does not normally print such an announcement, your work based on the Program is not
required to print an announcement.)