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GNU GENERAL PUBLIC LICENSE
Version 2, June 1991
Copyright (C) 1989, 1991 Free Software Foundation, Inc.
59 Temple Place, Suite 330, Boston, MA 02111-1307 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 Library 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 dis-
tribute 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 cer-
tain responsibilities for you if you distribute copies of
the software, or if you modify it.
For example, if you distribute copies of such a pro-
gram, whether gratis or for a fee, you must give the recipi-
ents 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, distribute and/or modify the soft-
ware.
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-
fied 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 reflect on the
original authors' reputations.
Finally, any free program is threatened constantly by
software patents. We wish to avoid the danger that redis-
tributors of a free program will individually obtain patent
licenses, in effect making the program proprietary. To pre-
vent 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, distri-
bution and modification follow.
GNU GENERAL PUBLIC LICENSE
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 modifications and/or translated into
another language. (Hereinafter, translation is included
without limitation in the term "modification".) Each
licensee is addressed as "you".
Activities other than copying, distribution and modification
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 con-
stitute 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 Pro-
gram's source code as you receive it, in any medium, pro-
vided 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 offer 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 modifications or work under the
terms of Section 1 above, provided that you also meet all of
these conditions:
a) You must cause the modified files to carry promi-
nent notices stating that you changed the files
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 modified 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 Pro-
gram is not required to print an announcement.)
These requirements apply to the modified work as a whole.
If identifiable sections of that work are not derived from
the Program, and can be reasonably considered independent
and separate works in themselves, then this License, and its
terms, do not apply to those sections when you distribute
them as separate works. But when you distribute the same
sections as part of a whole which is a work based on the
Program, the distribution of the whole must be on the terms
of this License, whose permissions for other licensees
extend to the entire whole, and thus to each and every part
regardless of who wrote it.
Thus, it is not the intent of this section to claim rights
or contest your rights to work written entirely by you;
rather, the intent is to exercise the right to control the
distribution of derivative or collective works based on the
Program.
In addition, mere aggregation of another work not based on
the Program with the Program (or with a work based on the
Program) on a volume of a storage or distribution medium
does not bring the other work under the scope of this
License.
3. You may copy and distribute the Program (or a work
based on it, under Section 2) in object code or executable
form under the terms of Sections 1 and 2 above provided that
you also do one of the following:
a) Accompany it with the complete corresponding
machine-readable source code, which must be dis-
tributed under the terms of Sections 1 and 2 above
on a medium customarily used for software inter-
change; or,
b) Accompany it with a written offer, valid for at
least three years, to give any third party, for a
charge no more than your cost of physically per-
forming source distribution, a complete machine-
readable copy of the corresponding source code, to
be distributed under the terms of Sections 1 and 2
above on a medium customarily used for software
interchange; or,
c) Accompany it with the information you received as
to the offer to distribute corresponding source
code. (This alternative is allowed only for non-
commercial distribution and only if you received
the program in object code or executable form with
such an offer, in accord with Subsection b above.)
The source code for a work means the preferred form of the
work for making modifications to it. For an executable
work, complete source code means all the source code for all
modules it contains, plus any associated interface defini-
tion files, plus the scripts used to control compilation and
installation of the executable. However, as a special
exception, the source code distributed need not include any-
thing that is normally distributed (in either source or
binary form) with the major components (compiler, kernel,
and so on) of the operating system on which the executable
runs, unless that component itself accompanies the exe-
cutable.
If distribution of executable or object code is made by
offering access to copy from a designated place, then offer-
ing equivalent access to copy the source code from the same
place counts as distribution of the source code, even though
third parties are not compelled to copy the source along
with the object code.
4. You may not copy, modify, sublicense, or distribute the
Program except as expressly provided under this License.
Any attempt otherwise to copy, modify, sublicense or dis-
tribute the Program is void, and will automatically termi-
nate your rights under this License. However, parties who
have received copies, or rights, from you under this License
will not have their licenses terminated so long as such par-
ties remain in full compliance.
5. You are not required to accept this License, since you
have not signed it. However, nothing else grants you per-
mission to modify or distribute the Program or its
derivative works. These actions are prohibited by law if
you do not accept this License. Therefore, by modifying or
distributing the Program (or any work based on the Program),
you indicate your acceptance of this License to do so, and
all its terms and conditions for copying, distributing or
modifying the Program or works based on it.
6. Each time you redistribute the Program (or any work
based on the Program), the recipient automatically receives
a license from the original licensor to copy, distribute or
modify the Program subject to these terms and conditions.
You may not impose any further restrictions on the recipi-
ents' exercise of the rights granted herein. You are not
responsible for enforcing compliance by third parties to
this License.
7. If, as a consequence of a court judgment or allegation
of patent infringement or for any other reason (not limited
to patent issues), conditions are imposed on you (whether by
court order, agreement or otherwise) that contradict the
conditions of this License, they do not excuse you from the
conditions of this License. If you cannot distribute so as
to satisfy simultaneously your obligations under this
License and any other pertinent obligations, then as a con-
sequence you may not distribute the Program at all. For
example, if a patent license would not permit royalty-free
redistribution of the Program by all those who receive
copies directly or indirectly through you, then the only way
you could satisfy both it and this License would be to
refrain entirely from distribution of the Program.
If any portion of this section is held invalid or unenforce-
able under any particular circumstance, the balance of the
section is intended to apply and the section as a whole is
intended to apply in other circumstances.
It is not the purpose of this section to induce you to
infringe any patents or other property right claims or to
contest validity of any such claims; this section has the
sole purpose of protecting the integrity of the free soft-
ware distribution system, which is implemented by public
license practices. Many people have made generous contribu-
tions to the wide range of software distributed through that
system in reliance on consistent application of that system;
it is up to the author/donor to decide if he or she is will-
ing to distribute software through any other system and a
licensee cannot impose that choice.
This section is intended to make thoroughly clear what is
believed to be a consequence of the rest of this License.
8. If the distribution and/or use of the Program is
restricted in certain countries either by patents or by
copyrighted interfaces, the original copyright holder who
places the Program under this License may add an explicit
geographical distribution limitation excluding those coun-
tries, so that distribution is permitted only in or among
countries not thus excluded. In such case, this License
incorporates the limitation as if written in the body of
this License.
9. The Free Software Foundation may publish revised and/or
new versions of the General Public License from time to
time. Such new versions will be similar in spirit to the
present version, but may differ in detail to address new
problems or concerns.
Each version is given a distinguishing version number. If
the Program specifies a version number of this License which
applies to it and "any later version", you have the option
of following the terms and conditions either of that version
or of any later version published by the Free Software Foun-
dation. If the Program does not specify a version number of
this License, you may choose any version ever published by
the Free Software Foundation.
10. If you wish to incorporate parts of the Program into
other free programs whose distribution conditions are dif-
ferent, write to the author to ask for permission. For
software which is copyrighted by the Free Software Founda-
tion, write to the Free Software Foundation; we sometimes
make exceptions for this. Our decision will be guided by
the two goals of preserving the free status of all deriva-
tives of our free software and of promoting the sharing and
reuse of software generally.
NO WARRANTY
11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE
IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE
COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM
"AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR
IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WAR-
RANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PUR-
POSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF
THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFEC-
TIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR
OR CORRECTION.
12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR
AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER
PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PER-
MITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARIS-
ING OUT OF THE USE OR INABILITY TO USE THE PROGRAM
(INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PAR-
TIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN
ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
END OF TERMS AND CONDITIONS
How to Apply These Terms to Your New Programs
If you develop a new program, and you want it to be of the
greatest possible use to the public, the best way to achieve
this is to make it free software which everyone can redis-
tribute and change under these terms.
To do so, attach the following notices to the program. It
is safest to attach them to the start of each source file to
most effectively convey the exclusion of warranty; and each
file should have at least the "copyright" line and a pointer
to where the full notice is found.
one line to give the program's name and a brief idea of what it does.
Copyright (C) year name of author
This program is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later ver-
sion.
This program is distributed in the hope that it will be use-
ful, but WITHOUT ANY WARRANTY; without even the implied war-
ranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR-
POSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public
License along with this program; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330,
Boston, MA 02111-1307 USA
Also add information on how to contact you by electronic and
paper mail.
If the program is interactive, make it output a short notice
like this when it starts in an interactive mode:
Gnomovision version 69, Copyright (C) year name of author
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
The hypothetical commands `show w' and `show c' should show
the appropriate parts of the General Public License. Of
course, the commands you use may be called something other
than `show w' and `show c'; they could even be mouse-clicks
or menu items--whatever suits your program.
You should also get your employer (if you work as a program-
mer) or your school, if any, to sign a "copyright dis-
claimer" for the program, if necessary. Here is a sample;
alter the names:
Yoyodyne, Inc., hereby disclaims all copyright interest in the program
`Gnomovision' (which makes passes at compilers) written by James Hacker.
signature of Ty Coon, 1 April 1989
Ty Coon, President of Vice
This General Public License does not permit incorporating
your program into proprietary programs. If your program is
a subroutine library, you may consider it more useful to
permit linking proprietary applications with the library.
If this is what you want to do, use the GNU Library General
Public License instead of this License.