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 copiesof this license document, but changing it is not allowed.
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) offer 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 modified 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
redistributors of a free program will individually obtain patent licenses, in
effect 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 modification follow.
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 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 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 prominent 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 Program 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 distributed under the terms of Sections 1 and 2 above on a medium
customarily used for software interchange; 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 performing
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 noncommercial 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 definition 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 anything 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 executable.
If distribution of executable or
object code is made by offering access to copy from a designated place, then
offering 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 distribute the Program is
void, and will automatically terminate 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 parties remain in full
compliance.
5. You are not required to accept this
License, since you have not signed it. However, nothing else grants you
permission 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 recipients' 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 consequence 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 unenforceable 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 software distribution system, which is
implemented by public license practices. Many people have made generous
contributions 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 willing 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 countries, 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 Foundation. 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 different,
write to the author to ask for permission. For software which is copyrighted by
the Free Software Foundation, 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 derivatives 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 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.
SHOULD THE PROGRAM PROVE DEFECTIVE, 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 PERMITTED ABOVE, BE LIABLE TO YOU
FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL
DAMAGES ARISING 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 PARTIES 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.