GNU (GENERAL PUBLIC LICENSE)
Version 3, 29 June 2007
Copyright © 2007 Free Software Foundation, Inc. <http://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
Preamble
The GNU General Public License is a free, copyleft license for software and other kinds of works.
The licenses for most software and other practical works are designed to take away your freedom to share and change the works. By
contrast, the GNU General Public License is intended to guarantee your freedom to share and change all versions of a program--to
make sure it remains free software for all its users. We, the Free Software Foundation, use the GNU General Public License for most of
our software; it applies also to any other work released this way by its authors. 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 them 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 prevent others from denying you these rights or asking you to surrender the rights. Therefore, you
have certain responsibilities if you distribute copies of the software, or if you modify it: responsibilities to respect the freedom of others.
For example, if you distribute copies of such a program, whether gratis or for a fee, you must pass on to the recipients the same
freedoms that you received. 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.
Developers that use the GNU GPL protect your rights with two steps: (1) assert copyright on the software, and (2) offer you this License
giving you legal permission to copy, distribute and/or modify it.
For the developers' and authors' protection, the GPL clearly explains that there is no warranty for this free software. For both users' and
authors' sake, the GPL requires that modified versions be marked as changed, so that their problems will not be attributed erroneously
to authors of previous versions.
Some devices are designed to deny users access to install or run modified versions of the software inside them, although the
manufacturer can do so. This is fundamentally incompatible with the aim of protecting users' freedom to change the software. The
systematic pattern of such abuse occurs in the area of products for individuals to use, which is precisely where it is most unacceptable.
Therefore, we have designed this version of the GPL to prohibit the practice for those products. If such problems arise substantially in
other domains, we stand ready to extend this provision to those domains in future versions of the GPL, as needed to protect the
freedom of users.
Finally, every program is threatened constantly by software patents. States should not allow patents to restrict development and use of
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The precise terms and conditions for copying, distribution and modification follow.
TERMS AND CONDITIONS
0. Definitions.
“This License” refers to version 3 of the GNU General Public License.
“Copyright” also means copyright-like laws that apply to other kinds of works, such as semiconductor masks.
“The Program” refers to any copyrightable work licensed under this License. Each licensee is addressed as “you”. “Licensees” and
“recipients” may be individuals or organizations.
To “modify” a work means to copy from or adapt all or part of the work in a fashion requiring copyright permission, other than the
making of an exact copy. The resulting work is called a “modified version” of the earlier work or a work “based on” the earlier work.
A “covered work” means either the unmodified Program or a work based on the Program.
To “propagate” a work means to do anything with it that, without permission, would make you directly or secondarily liable for
infringement under applicable copyright law, except executing it on a computer or modifying a private copy. Propagation includes
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To “convey” a work means any kind of propagation that enables other parties to make or receive copies. Mere interaction with a user
through a computer network, with no transfer of a copy, is not conveying.
An interactive user interface displays “Appropriate Legal Notices” to the extent that it includes a convenient and prominently visible
feature that (1) displays an appropriate copyright notice, and (2) tells the user that there is no warranty for the work (except to the
extent that warranties are provided), that licensees may convey the work under this License, and how to view a copy of this License. If
the interface presents a list of user commands or options, such as a menu, a prominent item in the list meets this criterion.
1. Source Code.
The “source code” for a work means the preferred form of the work for making modifications to it. “Object code” means any non-
source form of a work.
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A “Standard Interface” means an interface that either is an official standard defined by a recognized standards body, or, in the case of
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The “System Libraries” of an executable work include anything, other than the work as a whole, that (a) is included in the normal
form of packaging a Major Component, but which is not part of that Major Component, and (b) serves only to enable use of the work
with that Major Component, or to implement a Standard Interface for which an implementation is available to the public in source
code form. A “Major Component”, in this context, means a major essential component (kernel, window system, and so on) of the
specific operating system (if any) on which the executable work runs, or a compiler used to produce the work, or an object code
interpreter used to run it.
The “Corresponding Source” for a work in object code form means all the source code needed to generate, install, and (for an
executable work) run the object code and to modify the work, including scripts to control those activities. However, it does not include
the work's System Libraries, or general-purpose tools or generally available free programs which are used unmodified in performing
those activities but which are not part of the work. For example, Corresponding Source includes interface definition files associated with
source files for the work, and the source code for shared libraries and dynamically linked subprograms that the work is specifically
designed to require, such as by intimate data communication or control flow between those subprograms and other parts of the work.
The Corresponding Source need not include anything that users can regenerate automatically from other parts of the Corresponding
Source.
The Corresponding Source for a work in source code form is that same work.
2. Basic Permissions.
All rights granted under this License are granted for the term of copyright on the Program, and are irrevocable provided the stated
conditions are met. This License explicitly affirms your unlimited permission to run the unmodified Program. The output from running a
covered work is covered by this License only if the output, given its content, constitutes a covered work. This License acknowledges your
rights of fair use or other equivalent, as provided by copyright law.
You may make, run and propagate covered works that you do not convey, without conditions so long as your license otherwise remains
in force. You may convey covered works to others for the sole purpose of having them make modifications exclusively for you, or
provide you with facilities for running those works, provided that you comply with the terms of this License in conveying all material for
which you do not control copyright. Those thus making or running the covered works for you must do so exclusively on your behalf,
under your direction and control, on terms that prohibit them from making any copies of your copyrighted material outside their
relationship with you.
Conveying under any other circumstances is permitted solely under the conditions stated below. Sublicensing is not allowed; section 10
makes it unnecessary.
3. Protecting Users' Legal Rights From Anti-Circumvention Law.
No covered work shall be deemed part of an effective technological measure under any applicable law fulfilling obligations under
article 11 of the WIPO copyright treaty adopted on 20 December 1996, or similar laws prohibiting or restricting circumvention of such
measures.
When you convey a covered work, you waive any legal power to forbid circumvention of technological measures to the extent such
circumvention is effected by exercising rights under this License with respect to the covered work, and you disclaim any intention to
limit operation or modification of the work as a means of enforcing, against the work's users, your or third parties' legal rights to forbid
circumvention of technological measures.
4. Conveying Verbatim Copies.
You may convey 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; keep intact all notices stating that this License and any non-
permissive terms added in accord with section 7 apply to the code; keep intact all notices of the absence of any warranty; and give all
recipients a copy of this License along with the Program.
You may charge any price or no price for each copy that you convey, and you may offer support or warranty protection for a fee.
5. Conveying Modified Source Versions.
You may convey a work based on the Program, or the modifications to produce it from the Program, in the form of source code under
the terms of section 4, provided that you also meet all of these conditions:
a) The work must carry prominent notices stating that you modified it, and giving a relevant date.
b) The work must carry prominent notices stating that it is released under this License and any conditions added under section 7. This
requirement modifies the requirement in section 4 to “keep intact all notices”.
c) You must license the entire work, as a whole, under this License to anyone who comes into possession of a copy. This License will
therefore apply, along with any applicable section 7 additional terms, to the whole of the work, and all its parts, regardless of how
they are packaged. This License gives no permission to license the work in any other way, but it does not invalidate such permission if
you have separately received it.
d) If the work has interactive user interfaces, each must display Appropriate Legal Notices; however, if the Program has interactive
interfaces that do not display Appropriate Legal Notices, your work need not make them do so.
A compilation of a covered work with other separate and independent works, which are not by their nature extensions of the covered
work, and which are not combined with it such as to form a larger program, in or on a volume of a storage or distribution medium, is
called an “aggregate” if the compilation and its resulting copyright are not used to limit the access or legal rights of the compilation's
users beyond what the individual works permit. Inclusion of a covered work in an aggregate does not cause this License to apply to the
other parts of the aggregate.
6. Conveying Non-Source Forms.
You may convey a covered work in object code form under the terms of sections 4 and 5, provided that you also convey the machine-
readable Corresponding Source under the terms of this License, in one of these ways:
a) Convey the object code in, or embodied in, a physical product (including a physical distribution medium), accompanied by the
Corresponding Source fixed on a durable physical medium customarily used for software interchange.
b) Convey the object code in, or embodied in, a physical product (including a physical distribution medium), accompanied by a written
offer, valid for at least three years and valid for as long as you offer spare parts or customer support for that product model, to give
anyone who possesses the object code either (1) a copy of the Corresponding Source for all the software in the product that is covered
by this License, on a durable physical medium customarily used for software interchange, for a price no more than your reasonable
cost of physically performing this conveying of source, or (2) access to copy the Corresponding Source from a network server at no
charge.
