GNU Free Documentation License
Version 1.2, November 2002
Copyright (C) 2000,2001,2002 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.
The purpose of this License is to make a manual, textbook, or other
functional and useful document “free” in the sense of
freedom: to assure everyone the effective freedom to copy and
redistribute it, with or without modifying it, either commercially or
noncommercially. Secondarily, this License preserves for the author and
publisher a way to get credit for their work, while not being considered
responsible for modifications made by others.
This License is a kind of
copyleft, which means that
derivative works of the document must themselves be free in the same
sense. It complements the GNU General Public License, which is a copyleft
license designed for free software.
We have designed this License in order to use it for manuals for free
software, because free software needs free documentation: a free program
should come with manuals providing the same freedoms that the software
does. But this License is not limited to software manuals; it can be used
for any textual work, regardless of subject matter or whether it is
published as a printed book. We recommend this License principally for
works whose purpose is instruction or reference.
APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work, in any medium, that
contains a notice placed by the copyright holder saying it can be
distributed under the terms of this License. Such a notice grants a
world-wide, royalty-free license, unlimited in duration, to use that work
under the conditions stated herein. The
refers to any such manual or work. Any member of the public is a
licensee, and is addressed as
you. You accept the license
if you copy, modify or distribute the work in a way requiring permission
under copyright law.
Modified Version of the Document means any work
containing the Document or a portion of it, either copied verbatim, or
with modifications and/or translated into another language.
Secondary Section is a named appendix or a front-matter
section of the Document that deals exclusively with the relationship of
the publishers or authors of the Document to the Document’s overall
subject (or to related matters) and contains nothing that could fall
directly within that overall subject. (Thus, if the Document is in part a
textbook of mathematics, a Secondary Section may not explain any
mathematics.) The relationship could be a matter of historical connection
with the subject or with related matters, or of legal, commercial,
philosophical, ethical or political position regarding them.
Invariant Sections are certain Secondary Sections
whose titles are designated, as being those of Invariant Sections, in the
notice that says that the Document is released under this License. If a
section does not fit the above definition of Secondary then it is not
allowed to be designated as Invariant. The Document may contain zero
Invariant Sections. If the Document does not identify any Invariant
Sections then there are none.
Cover Texts are certain short passages of text that
are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that
says that the Document is released under this License. A Front-Cover Text
may be at most 5 words, and a Back-Cover Text may be at most 25 words.
Transparent copy of the Document means a
machine-readable copy, represented in a format whose specification is
available to the general public, that is suitable for revising the
document straightforwardly with generic text editors or (for images
composed of pixels) generic paint programs or (for drawings) some widely
available drawing editor, and that is suitable for input to text
formatters or for automatic translation to a variety of formats suitable
for input to text formatters. A copy made in an otherwise Transparent
file format whose markup, or absence of markup, has been arranged to
thwart or discourage subsequent modification by readers is not
Transparent. An image format is not Transparent if used for any
substantial amount of text. A copy that is not
Examples of suitable formats for Transparent copies include plain ASCII
without markup, Texinfo input format, LaTeX input format, SGML or XML
using a publicly available DTD, and standard-conforming simple HTML,
PostScript or PDF designed for human modification. Examples of
transparent image formats include PNG, XCF and JPG. Opaque formats
include proprietary formats that can be read and edited only by
proprietary word processors, SGML or XML for which the DTD and/or
processing tools are not generally available, and the machine-generated
HTML, PostScript or PDF produced by some word processors for output
Title Page means, for a printed book, the title page
itself, plus such following pages as are needed to hold, legibly, the
material this License requires to appear in the title page. For works in
formats which do not have any title page as such,
Page means the text near the most prominent appearance of the
work’s title, preceding the beginning of the body of the text.
Entitled XYZ means a named subunit of the
Document whose title either is precisely XYZ or contains XYZ in
parentheses following text that translates XYZ in another language. (Here
XYZ stands for a specific section name mentioned below, such as
Preserve the Title of such a section when you modify the
Document means that it remains a section
according to this definition.
The Document may include Warranty Disclaimers next to the notice which
states that this License applies to the Document. These Warranty
Disclaimers are considered to be included by reference in this License,
but only as regards disclaiming warranties: any other implication that
these Warranty Disclaimers may have is void and has no effect on the
meaning of this License.
You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License applies to
the Document are reproduced in all copies, and that you add no other
conditions whatsoever to those of this License. You may not use technical
measures to obstruct or control the reading or further copying of the
copies you make or distribute. However, you may accept compensation in
exchange for copies. If you distribute a large enough number of copies
you must also follow the conditions in section 3.
You may also lend copies, under the same conditions stated above, and you
may publicly display copies.
COPYING IN QUANTITY
If you publish printed copies (or copies in media that commonly have
printed covers) of the Document, numbering more than 100, and the
Document’s license notice requires Cover Texts, you must enclose
the copies in covers that carry, clearly and legibly, all these Cover
Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the
back cover. Both covers must also clearly and legibly identify you as the
publisher of these copies. The front cover must present the full title
with all words of the title equally prominent and visible. You may add
other material on the covers in addition. Copying with changes limited to
the covers, as long as they preserve the title of the Document and
satisfy these conditions, can be treated as verbatim copying in other
If the required texts for either cover are too voluminous to fit legibly,
you should put the first ones listed (as many as fit reasonably) on the
actual cover, and continue the rest onto adjacent pages.
If you publish or distribute Opaque copies of the Document numbering more
than 100, you must either include a machine-readable Transparent copy
along with each Opaque copy, or state in or with each Opaque copy a
computer-network location from which the general network-using public has
access to download using public-standard network protocols a complete
Transparent copy of the Document, free of added material. If you use the
latter option, you must take reasonably prudent steps, when you begin
distribution of Opaque copies in quantity, to ensure that this
Transparent copy will remain thus accessible at the stated location until
at least one year after the last time you distribute an Opaque copy
(directly or through your agents or retailers) of that edition to the
It is requested, but not required, that you contact the authors of the
Document well before redistributing any large number of copies, to give
them a chance to provide you with an updated version of the Document.
You may copy and distribute a Modified Version of the Document under the
conditions of sections 2 and 3 above, provided that you release the
Modified Version under precisely this License, with the Modified Version
filling the role of the Document, thus licensing distribution and
modification of the Modified Version to whoever possesses a copy of it.
In addition, you must do these things in the Modified Version:
Use in the Title Page (and on the covers, if any) a title distinct from
that of the Document, and from those of previous versions (which should,
if there were any, be listed in the History section of the Document).
You may use the same title as a previous version if the original
publisher of that version gives permission.
List on the Title Page, as authors, one or more persons or entities
responsible for authorship of the modifications in the Modified Version,
together with at least five of the principal authors of the Document
(all of its principal authors, if it has fewer than five), unless they
release you from this requirement.
State on the Title page the name of the publisher of the Modified
Version, as the publisher.
Preserve all the copyright notices of the Document.
Add an appropriate copyright notice for your modifications adjacent to
the other copyright notices.
Include, immediately after the copyright notices, a license notice
giving the public permission to use the Modified Version under the terms
of this License, in the form shown in the Addendum below.
Preserve in that license notice the full lists of Invariant Sections and
required Cover Texts given in the Document’s license notice.
Include an unaltered copy of this License.
Preserve the section Entitled
History, Preserve its
Title, and add to it an item stating at least the title, year, new
authors, and publisher of the Modified Version as given on the Title
Page. If there is no section Entitled
History in the
Document, create one stating the title, year, authors, and publisher of
the Document as given on its Title Page, then add an item describing the
Modified Version as stated in the previous sentence.
Preserve the network location, if any, given in the Document for public
access to a Transparent copy of the Document, and likewise the network
locations given in the Document for previous versions it was based on.
These may be placed in the
History section. You may omit
a network location for a work that was published at least four years
before the Document itself, or if the original publisher of the version
it refers to gives permission.
For any section Entitled
Dedications, Preserve the Title of the section, and
preserve in the section all the substance and tone of each of the
contributor acknowledgements and/or dedications given therein.
Preserve all the Invariant Sections of the Document, unaltered in their
text and in their titles. Section numbers or the equivalent are not
considered part of the section titles.
Delete any section Entitled
Endorsements. Such a section
may not be included in the Modified Version.
Do not retitle any existing section to be Entitled
Endorsements or to conflict in title with any Invariant
Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or appendices
that qualify as Secondary Sections and contain no material copied from
the Document, you may at your option designate some or all of these
sections as invariant. To do this, add their titles to the list of
Invariant Sections in the Modified Version’s license notice. These
titles must be distinct from any other section titles.
You may add a section Entitled
Endorsements, provided it
contains nothing but endorsements of your Modified Version by various
parties--for example, statements of peer review or that the text has been
approved by an organization as the authoritative definition of a
You may add a passage of up to five words as a Front-Cover Text, and a
passage of up to 25 words as a Back-Cover Text, to the end of the list of
Cover Texts in the Modified Version. Only one passage of Front-Cover Text
and one of Back-Cover Text may be added by (or through arrangements made
by) any one entity. If the Document already includes a cover text for the
same cover, previously added by you or by arrangement made by the same
entity you are acting on behalf of, you may not add another; but you may
replace the old one, on explicit permission from the previous publisher
that added the old one.
The author(s) and publisher(s) of the Document do not by this License
give permission to use their names for publicity for or to assert or
imply endorsement of any Modified Version.
You may combine the Document with other documents released under this
License, under the terms defined in section 4 above for modified
versions, provided that you include in the combination all of the
Invariant Sections of all of the original documents, unmodified, and list
them all as Invariant Sections of your combined work in its license
notice, and that you preserve all their Warranty Disclaimers.
The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single copy.
If there are multiple Invariant Sections with the same name but different
contents, make the title of each such section unique by adding at the end
of it, in parentheses, the name of the original author or publisher of
that section if known, or else a unique number. Make the same adjustment
to the section titles in the list of Invariant Sections in the license
notice of the combined work.
In the combination, you must combine any sections Entitled
History in the various original documents, forming one
History; likewise combine any sections
Acknowledgements, and any sections Entitled
Dedications. You must delete all sections Entitled
COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other documents
released under this License, and replace the individual copies of this
License in the various documents with a single copy that is included in
the collection, provided that you follow the rules of this License for
verbatim copying of each of the documents in all other respects.
You may extract a single document from such a collection, and distribute
it individually under this License, provided you insert a copy of this
License into the extracted document, and follow this License in all other
respects regarding verbatim copying of that document.
AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other separate and
independent documents or works, in or on a volume of a storage or
distribution medium, is called an “aggregate” if the
copyright resulting from the compilation is not used to limit the legal
rights of the compilation’s users beyond what the individual works
permit. When the Document is included in an aggregate, this License does
not apply to the other works in the aggregate which are not themselves
derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these copies
of the Document, then if the Document is less than one half of the entire
aggregate, the Document’s Cover Texts may be placed on covers that
bracket the Document within the aggregate, or the electronic equivalent
of covers if the Document is in electronic form. Otherwise they must
appear on printed covers that bracket the whole aggregate.
Translation is considered a kind of modification, so you may distribute
translations of the Document under the terms of section 4. Replacing
Invariant Sections with translations requires special permission from
their copyright holders, but you may include translations of some or all
Invariant Sections in addition to the original versions of these
Invariant Sections. You may include a translation of this License, and
all the license notices in the Document, and any Warranty Disclaimers,
provided that you also include the original English version of this
License and the original versions of those notices and disclaimers. In
case of a disagreement between the translation and the original version
of this License or a notice or disclaimer, the original version will
If a section in the Document is Entitled
History, the requirement
(section 4) to Preserve its Title (section 1) will typically require
changing the actual title.
You may not copy, modify, sublicense, or distribute the Document except
as expressly provided for under this License. Any other attempt to copy,
modify, sublicense or distribute the Document 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
FUTURE REVISIONS OF THIS LICENSE
The Free Software Foundation may publish new, revised versions of the GNU
Free Documentation 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. See
Each version of the License is given a distinguishing version number. If
the Document specifies that a particular numbered version of this License
or any later version applies to it, you have the option of
following the terms and conditions either of that specified version or of
any later version that has been published (not as a draft) by the Free
Software Foundation. If the Document does not specify a version number of
this License, you may choose any version ever published (not as a draft)
by the Free Software Foundation.
ADDENDUM: How to use this License for your documents
To use this License in a document you have written, include a copy of the
License in the document and put the following copyright and license
notices just after the title page:
Copyright (c) YEAR YOUR NAME.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2
only as published by the Free Software Foundation;
with the Invariant Section being this copyright notice and license.
A copy of the license is included in the section entitled “GNU
Free Documentation License”.
If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the “with...Texts.” line with this:
with the Invariant Sections being LIST THEIR TITLES, with the
Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.
If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of free
software license, such as the GNU General Public License, to permit their
use in free software.