1.. Permission is granted to copy, distribute and/or modify this
2.. document under the terms of the GNU Free Documentation License,
3.. Version 1.1 or any later version published by the Free Software
4.. Foundation, with no Invariant Sections, no Front-Cover Texts
5.. and no Back-Cover Texts. A copy of the license is included at
6.. Documentation/userspace-api/media/fdl-appendix.rst.
7..
8.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
9
10.. _fdl:
11
12******************************
13GNU Free Documentation License
14******************************
15
16
17.. _fdl-preamble:
18
190. PREAMBLE
20===========
21
22The purpose of this License is to make a manual, textbook, or other
23written document “free” in the sense of freedom: to assure everyone the
24effective freedom to copy and redistribute it, with or without modifying
25it, either commercially or noncommercially. Secondarily, this License
26preserves for the author and publisher a way to get credit for their
27work, while not being considered responsible for modifications made by
28others.
29
30This License is a kind of “copyleft”, which means that derivative works
31of the document must themselves be free in the same sense. It
32complements the GNU General Public License, which is a copyleft license
33designed for free software.
34
35We have designed this License in order to use it for manuals for free
36software, because free software needs free documentation: a free program
37should come with manuals providing the same freedoms that the software
38does. But this License is not limited to software manuals; it can be
39used for any textual work, regardless of subject matter or whether it is
40published as a printed book. We recommend this License principally for
41works whose purpose is instruction or reference.
42
43
44.. _fdl-section1:
45
461. APPLICABILITY AND DEFINITIONS
47================================
48
49
50.. _fdl-document:
51
52This License applies to any manual or other work that contains a notice
53placed by the copyright holder saying it can be distributed under the
54terms of this License. The “Document”, below, refers to any such manual
55or work. Any member of the public is a licensee, and is addressed as
56“you”.
57
58
59.. _fdl-modified:
60
61A “Modified Version” of the Document means any work containing the
62Document or a portion of it, either copied verbatim, or with
63modifications and/or translated into another language.
64
65
66.. _fdl-secondary:
67
68A “Secondary Section” is a named appendix or a front-matter section of
69the :ref:`Document <fdl-document>` that deals exclusively with the
70relationship of the publishers or authors of the Document to the
71Document's overall subject (or to related matters) and contains nothing
72that could fall directly within that overall subject. (For example, if
73the Document is in part a textbook of mathematics, a Secondary Section
74may not explain any mathematics.) The relationship could be a matter of
75historical connection with the subject or with related matters, or of
76legal, commercial, philosophical, ethical or political position
77regarding them.
78
79
80.. _fdl-invariant:
81
82The “Invariant Sections” are certain
83:ref:`Secondary Sections <fdl-secondary>` whose titles are designated,
84as being those of Invariant Sections, in the notice that says that the
85:ref:`Document <fdl-document>` is released under this License.
86
87
88.. _fdl-cover-texts:
89
90The “Cover Texts” are certain short passages of text that are listed, as
91Front-Cover Texts or Back-Cover Texts, in the notice that says that the
92:ref:`Document <fdl-document>` is released under this License.
93
94
95.. _fdl-transparent:
96
97A “Transparent” copy of the :ref:`Document <fdl-document>` means a
98machine-readable copy, represented in a format whose specification is
99available to the general public, whose contents can be viewed and edited
100directly and straightforwardly with generic text editors or (for images
101composed of pixels) generic paint programs or (for drawings) some widely
102available drawing editor, and that is suitable for input to text
103formatters or for automatic translation to a variety of formats suitable
104for input to text formatters. A copy made in an otherwise Transparent
105file format whose markup has been designed to thwart or discourage
106subsequent modification by readers is not Transparent. A copy that is
107not “Transparent” is called “Opaque”.
108
109Examples of suitable formats for Transparent copies include plain ASCII
110without markup, Texinfo input format, LaTeX input format, SGML or XML
111using a publicly available DTD, and standard-conforming simple HTML
112designed for human modification. Opaque formats include PostScript, PDF,
113proprietary formats that can be read and edited only by proprietary word
114processors, SGML or XML for which the DTD and/or processing tools are
115not generally available, and the machine-generated HTML produced by some
116word processors for output purposes only.
117
118
119.. _fdl-title-page:
120
121The “Title Page” means, for a printed book, the title page itself, plus
122such following pages as are needed to hold, legibly, the material this
123License requires to appear in the title page. For works in formats which
124do not have any title page as such, “Title Page” means the text near the
125most prominent appearance of the work's title, preceding the beginning
126of the body of the text.
127
128
129.. _fdl-section2:
130
1312. VERBATIM COPYING
132===================
133
134You may copy and distribute the :ref:`Document <fdl-document>` in any
135medium, either commercially or noncommercially, provided that this
136License, the copyright notices, and the license notice saying this
137License applies to the Document are reproduced in all copies, and that
138you add no other conditions whatsoever to those of this License. You may
139not use technical measures to obstruct or control the reading or further
140copying of the copies you make or distribute. However, you may accept
141compensation in exchange for copies. If you distribute a large enough
142number of copies you must also follow the conditions in
143:ref:`section 3 <fdl-section3>`.
144
145You may also lend copies, under the same conditions stated above, and
146you may publicly display copies.
147
148
149.. _fdl-section3:
150
1513. COPYING IN QUANTITY
152======================
153
154If you publish printed copies of the :ref:`Document <fdl-document>`
155numbering more than 100, and the Document's license notice requires
156:ref:`Cover Texts <fdl-cover-texts>`, you must enclose the copies in
157covers that carry, clearly and legibly, all these Cover Texts:
158Front-Cover Texts on the front cover, and Back-Cover Texts on the back
159cover. Both covers must also clearly and legibly identify you as the
160publisher of these copies. The front cover must present the full title
161with all words of the title equally prominent and visible. You may add
162other material on the covers in addition. Copying with changes limited
163to the covers, as long as they preserve the title of the
164:ref:`Document <fdl-document>` and satisfy these conditions, can be
165treated as verbatim copying in other respects.
166
167If the required texts for either cover are too voluminous to fit
168legibly, you should put the first ones listed (as many as fit
169reasonably) on the actual cover, and continue the rest onto adjacent
170pages.
171
172If you publish or distribute :ref:`Opaque <fdl-transparent>` copies of
173the :ref:`Document <fdl-document>` numbering more than 100, you must
174either include a machine-readable :ref:`Transparent <fdl-transparent>`
175copy along with each Opaque copy, or state in or with each Opaque copy a
176publicly-accessible computer-network location containing a complete
177Transparent copy of the Document, free of added material, which the
178general network-using public has access to download anonymously at no
179charge using public-standard network protocols. If you use the latter
180option, you must take reasonably prudent steps, when you begin
181distribution of Opaque copies in quantity, to ensure that this
182Transparent copy will remain thus accessible at the stated location
183until at least one year after the last time you distribute an Opaque
184copy (directly or through your agents or retailers) of that edition to
185the public.
186
187It is requested, but not required, that you contact the authors of the
188:ref:`Document <fdl-document>` well before redistributing any large
189number of copies, to give them a chance to provide you with an updated
190version of the Document.
191
192
193.. _fdl-section4:
194
1954. MODIFICATIONS
196================
197
198You may copy and distribute a :ref:`Modified Version <fdl-modified>`
199of the :ref:`Document <fdl-document>` under the conditions of sections
200:ref:`2 <fdl-section2>` and :ref:`3 <fdl-section3>` above, provided
201that you release the Modified Version under precisely this License, with
202the Modified Version filling the role of the Document, thus licensing
203distribution and modification of the Modified Version to whoever
204possesses a copy of it. In addition, you must do these things in the
205Modified Version:
206
207-  **A.**
208   Use in the :ref:`Title Page <fdl-title-page>` (and on the covers,
209   if any) a title distinct from that of the
210   :ref:`Document <fdl-document>`, and from those of previous versions
211   (which should, if there were any, be listed in the History section of
212   the Document). You may use the same title as a previous version if
213   the original publisher of that version gives permission.
214
215-  **B.**
216   List on the :ref:`Title Page <fdl-title-page>`, as authors, one or
217   more persons or entities responsible for authorship of the
218   modifications in the :ref:`Modified Version <fdl-modified>`,
219   together with at least five of the principal authors of the
220   :ref:`Document <fdl-document>` (all of its principal authors, if it
221   has less than five).
222
223-  **C.**
224   State on the :ref:`Title Page <fdl-title-page>` the name of the
225   publisher of the :ref:`Modified Version <fdl-modified>`, as the
226   publisher.
227
228-  **D.**
229   Preserve all the copyright notices of the
230   :ref:`Document <fdl-document>`.
231
232-  **E.**
233   Add an appropriate copyright notice for your modifications adjacent
234   to the other copyright notices.
235
236-  **F.**
237   Include, immediately after the copyright notices, a license notice
238   giving the public permission to use the
239   :ref:`Modified Version <fdl-modified>` under the terms of this
240   License, in the form shown in the Addendum below.
241
242-  **G.**
243   Preserve in that license notice the full lists of
244   :ref:`Invariant Sections <fdl-invariant>` and required
245   :ref:`Cover Texts <fdl-cover-texts>` given in the
246   :ref:`Document's <fdl-document>` license notice.
247
248-  **H.**
249   Include an unaltered copy of this License.
250
251-  **I.**
252   Preserve the section entitled “History”, and its title, and add to it
253   an item stating at least the title, year, new authors, and publisher
254   of the :ref:`Modified Version <fdl-modified>` as given on the
255   :ref:`Title Page <fdl-title-page>`. If there is no section entitled
256   “History” in the :ref:`Document <fdl-document>`, create one stating
257   the title, year, authors, and publisher of the Document as given on
258   its Title Page, then add an item describing the Modified Version as
259   stated in the previous sentence.
260
261-  **J.**
262   Preserve the network location, if any, given in the
263   :ref:`Document <fdl-document>` for public access to a
264   :ref:`Transparent <fdl-transparent>` copy of the Document, and
265   likewise the network locations given in the Document for previous
266   versions it was based on. These may be placed in the “History”
267   section. You may omit a network location for a work that was
268   published at least four years before the Document itself, or if the
269   original publisher of the version it refers to gives permission.
270
271-  **K.**
272   In any section entitled “Acknowledgements” or “Dedications”, preserve
273   the section's title, and preserve in the section all the substance
274   and tone of each of the contributor acknowledgements and/or
275   dedications given therein.
276
277-  **L.**
278   Preserve all the :ref:`Invariant Sections <fdl-invariant>` of the
279   :ref:`Document <fdl-document>`, unaltered in their text and in
280   their titles. Section numbers or the equivalent are not considered
281   part of the section titles.
282
283-  **M.**
284   Delete any section entitled “Endorsements”. Such a section may not be
285   included in the :ref:`Modified Version <fdl-modified>`.
286
287-  **N.**
288   Do not retitle any existing section as “Endorsements” or to conflict
289   in title with any :ref:`Invariant Section <fdl-invariant>`.
290
291If the :ref:`Modified Version <fdl-modified>` includes new
292front-matter sections or appendices that qualify as
293:ref:`Secondary Sections <fdl-secondary>` and contain no material
294copied from the Document, you may at your option designate some or all
295of these sections as invariant. To do this, add their titles to the list
296of :ref:`Invariant Sections <fdl-invariant>` in the Modified Version's
297license notice. These titles must be distinct from any other section
298titles.
299
300You may add a section entitled “Endorsements”, provided it contains
301nothing but endorsements of your
302:ref:`Modified Version <fdl-modified>` by various parties--for
303example, statements of peer review or that the text has been approved by
304an organization as the authoritative definition of a standard.
305
306You may add a passage of up to five words as a
307:ref:`Front-Cover Text <fdl-cover-texts>`, and a passage of up to 25
308words as a :ref:`Back-Cover Text <fdl-cover-texts>`, to the end of the
309list of :ref:`Cover Texts <fdl-cover-texts>` in the
310:ref:`Modified Version <fdl-modified>`. Only one passage of
311Front-Cover Text and one of Back-Cover Text may be added by (or through
312arrangements made by) any one entity. If the
313:ref:`Document <fdl-document>` already includes a cover text for the
314same cover, previously added by you or by arrangement made by the same
315entity you are acting on behalf of, you may not add another; but you may
316replace the old one, on explicit permission from the previous publisher
317that added the old one.
318
319The author(s) and publisher(s) of the :ref:`Document <fdl-document>`
320do not by this License give permission to use their names for publicity
321for or to assert or imply endorsement of any
322:ref:`Modified Version <fdl-modified>`.
323
324
325.. _fdl-section5:
326
3275. COMBINING DOCUMENTS
328======================
329
330You may combine the :ref:`Document <fdl-document>` with other
331documents released under this License, under the terms defined in
332:ref:`section 4 <fdl-section4>` above for modified versions, provided
333that you include in the combination all of the
334:ref:`Invariant Sections <fdl-invariant>` of all of the original
335documents, unmodified, and list them all as Invariant Sections of your
336combined work in its license notice.
337
338The combined work need only contain one copy of this License, and
339multiple identical :ref:`Invariant Sections <fdl-invariant>` may be
340replaced with a single copy. If there are multiple Invariant Sections
341with the same name but different contents, make the title of each such
342section unique by adding at the end of it, in parentheses, the name of
343the original author or publisher of that section if known, or else a
344unique number. Make the same adjustment to the section titles in the
345list of Invariant Sections in the license notice of the combined work.
346
347In the combination, you must combine any sections entitled “History” in
348the various original documents, forming one section entitled “History”;
349likewise combine any sections entitled “Acknowledgements”, and any
350sections entitled “Dedications”. You must delete all sections entitled
351“Endorsements.”
352
353
354.. _fdl-section6:
355
3566. COLLECTIONS OF DOCUMENTS
357===========================
358
359You may make a collection consisting of the
360:ref:`Document <fdl-document>` and other documents released under this
361License, and replace the individual copies of this License in the
362various documents with a single copy that is included in the collection,
363provided that you follow the rules of this License for verbatim copying
364of each of the documents in all other respects.
365
366You may extract a single document from such a collection, and distribute
367it individually under this License, provided you insert a copy of this
368License into the extracted document, and follow this License in all
369other respects regarding verbatim copying of that document.
370
371
372.. _fdl-section7:
373
3747. AGGREGATION WITH INDEPENDENT WORKS
375=====================================
376
377A compilation of the :ref:`Document <fdl-document>` or its derivatives
378with other separate and independent documents or works, in or on a
379volume of a storage or distribution medium, does not as a whole count as
380a :ref:`Modified Version <fdl-modified>` of the Document, provided no
381compilation copyright is claimed for the compilation. Such a compilation
382is called an “aggregate”, and this License does not apply to the other
383self-contained works thus compiled with the Document , on account of
384their being thus compiled, if they are not themselves derivative works
385of the Document. If the :ref:`Cover Text <fdl-cover-texts>`
386requirement of :ref:`section 3 <fdl-section3>` is applicable to these
387copies of the Document, then if the Document is less than one quarter of
388the entire aggregate, the Document's Cover Texts may be placed on covers
389that surround only the Document within the aggregate. Otherwise they
390must appear on covers around the whole aggregate.
391
392
393.. _fdl-section8:
394
3958. TRANSLATION
396==============
397
398Translation is considered a kind of modification, so you may distribute
399translations of the :ref:`Document <fdl-document>` under the terms of
400:ref:`section 4 <fdl-section4>`. Replacing
401:ref:`Invariant Sections <fdl-invariant>` with translations requires
402special permission from their copyright holders, but you may include
403translations of some or all Invariant Sections in addition to the
404original versions of these Invariant Sections. You may include a
405translation of this License provided that you also include the original
406English version of this License. In case of a disagreement between the
407translation and the original English version of this License, the
408original English version will prevail.
409
410
411.. _fdl-section9:
412
4139. TERMINATION
414==============
415
416You may not copy, modify, sublicense, or distribute the
417:ref:`Document <fdl-document>` except as expressly provided for under
418this License. Any other attempt to copy, modify, sublicense or
419distribute the Document is void, and will automatically terminate your
420rights under this License. However, parties who have received copies, or
421rights, from you under this License will not have their licenses
422terminated so long as such parties remain in full compliance.
423
424
425.. _fdl-section10:
426
42710. FUTURE REVISIONS OF THIS LICENSE
428====================================
429
430The `Free Software Foundation <http://www.gnu.org/fsf/fsf.html>`__
431may publish new, revised versions of the GNU Free Documentation License
432from time to time. Such new versions will be similar in spirit to the
433present version, but may differ in detail to address new problems or
434concerns. See
435`http://www.gnu.org/copyleft/ <http://www.gnu.org/copyleft>`__.
436
437Each version of the License is given a distinguishing version number. If
438the :ref:`Document <fdl-document>` specifies that a particular
439numbered version of this License “or any later version” applies to it,
440you have the option of following the terms and conditions either of that
441specified version or of any later version that has been published (not
442as a draft) by the Free Software Foundation. If the Document does not
443specify a version number of this License, you may choose any version
444ever published (not as a draft) by the Free Software Foundation.
445
446
447.. _fdl-using:
448
449Addendum
450========
451
452To use this License in a document you have written, include a copy of
453the License in the document and put the following copyright and license
454notices just after the title page:
455
456    Copyright © YEAR YOUR NAME.
457
458    Permission is granted to copy, distribute and/or modify this
459    document under the terms of the GNU Free Documentation License,
460    Version 1.1 or any later version published by the Free Software
461    Foundation; with the :ref:`Invariant Sections <fdl-invariant>`
462    being LIST THEIR TITLES, with the
463    :ref:`Front-Cover Texts <fdl-cover-texts>` being LIST, and with
464    the :ref:`Back-Cover Texts <fdl-cover-texts>` being LIST. A copy
465    of the license is included in the section entitled “GNU Free
466    Documentation License”.
467
468If you have no :ref:`Invariant Sections <fdl-invariant>`, write “with
469no Invariant Sections” instead of saying which ones are invariant. If
470you have no :ref:`Front-Cover Texts <fdl-cover-texts>`, write “no
471Front-Cover Texts” instead of “Front-Cover Texts being LIST”; likewise
472for :ref:`Back-Cover Texts <fdl-cover-texts>`.
473
474If your document contains nontrivial examples of program code, we
475recommend releasing these examples in parallel under your choice of free
476software license, such as the
477`GNU General Public License <http://www.gnu.org/copyleft/gpl.html>`__,
478to permit their use in free software.
479