1.. _gnu_fdl: 2 3****************************** 4GNU Free Documentation License 5****************************** 6 7Version 1.3, 3 November 2008 8 9Copyright 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc 10http://fsf.org/ 11 12Everyone is permitted to copy and distribute verbatim copies of this 13license document, but changing it is not allowed. 14 15**Preamble** 16 17The purpose of this License is to make a manual, textbook, or other 18functional and useful document "free" in the sense of freedom: to 19assure everyone the effective freedom to copy and redistribute it, 20with or without modifying it, either commercially or noncommercially. 21Secondarily, this License preserves for the author and publisher a way 22to get credit for their work, while not being considered responsible 23for modifications made by others. 24 25This License is a kind of "copyleft", which means that derivative 26works of the document must themselves be free in the same sense. It 27complements the GNU General Public License, which is a copyleft 28license designed for free software. 29 30We have designed this License in order to use it for manuals for free 31software, because free software needs free documentation: a free 32program should come with manuals providing the same freedoms that the 33software does. But this License is not limited to software manuals; 34it can be used for any textual work, regardless of subject matter or 35whether it is published as a printed book. We recommend this License 36principally for works whose purpose is instruction or reference. 37 38**1. APPLICABILITY AND DEFINITIONS** 39 40This License applies to any manual or other work, in any medium, that 41contains a notice placed by the copyright holder saying it can be 42distributed under the terms of this License. Such a notice grants a 43world-wide, royalty-free license, unlimited in duration, to use that 44work under the conditions stated herein. The **Document**, below, 45refers to any such manual or work. Any member of the public is a 46licensee, and is addressed as "**you**". You accept the license if you 47copy, modify or distribute the work in a way requiring permission 48under copyright law. 49 50A "**Modified Version**" of the Document means any work containing the 51Document or a portion of it, either copied verbatim, or with 52modifications and/or translated into another language. 53 54A "**Secondary Section**" is a named appendix or a front-matter section of 55the Document that deals exclusively with the relationship of the 56publishers or authors of the Document to the Document's overall subject 57(or to related matters) and contains nothing that could fall directly 58within that overall subject. (Thus, if the Document is in part a 59textbook of mathematics, a Secondary Section may not explain any 60mathematics.) 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A copy that is not "Transparent" is called **Opaque**. 90 91Examples of suitable formats for Transparent copies include plain 92ASCII without markup, Texinfo input format, LaTeX input format, SGML 93or XML using a publicly available DTD, and standard-conforming simple 94HTML, PostScript or PDF designed for human modification. Examples of 95transparent image formats include PNG, XCF and JPG. Opaque formats 96include proprietary formats that can be read and edited only by 97proprietary word processors, SGML or XML for which the DTD and/or 98processing tools are not generally available, and the 99machine-generated HTML, PostScript or PDF produced by some word 100processors for output purposes only. 101 102The "**Title Page**" means, for a printed book, the title page itself, 103plus such following pages as are needed to hold, legibly, the material 104this License requires to appear in the title page. For works in 105formats which do not have any title page as such, "Title Page" means 106the text near the most prominent appearance of the work's title, 107preceding the beginning of the body of the text. 108 109The "**publisher**" means any person or entity that distributes 110copies of the Document to the public. 111 112A section "**Entitled XYZ**" means a named subunit of the Document whose 113title either is precisely XYZ or contains XYZ in parentheses following 114text that translates XYZ in another language. (Here XYZ stands for a 115specific section name mentioned below, such as "**Acknowledgements**", 116"**Dedications**", "**Endorsements**", or "**History**".) 117To "**Preserve the Title**" 118of such a section when you modify the Document means that it remains a 119section "Entitled XYZ" according to this definition. 120 121The Document may include Warranty Disclaimers next to the notice which 122states that this License applies to the Document. These Warranty 123Disclaimers are considered to be included by reference in this 124License, but only as regards disclaiming warranties: any other 125implication that these Warranty Disclaimers may have is void and has 126no effect on the meaning of this License. 127 128**2. VERBATIM COPYING** 129 130You may copy and distribute the Document in any medium, either 131commercially or noncommercially, provided that this License, the 132copyright notices, and the license notice saying this License applies 133to the Document are reproduced in all copies, and that you add no other 134conditions whatsoever to those of this License. You may not use 135technical measures to obstruct or control the reading or further 136copying of the copies you make or distribute. However, you may accept 137compensation in exchange for copies. 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MODIFICATIONS** 181 182You may copy and distribute a Modified Version of the Document under 183the conditions of sections 2 and 3 above, provided that you release 184the Modified Version under precisely this License, with the Modified 185Version filling the role of the Document, thus licensing distribution 186and modification of the Modified Version to whoever possesses a copy 187of it. In addition, you must do these things in the Modified Version: 188 189A. Use in the Title Page (and on the covers, if any) a title distinct 190 from that of the Document, and from those of previous versions 191 (which should, if there were any, be listed in the History section 192 of the Document). You may use the same title as a previous version 193 if the original publisher of that version gives permission. 194 195B. List on the Title Page, as authors, one or more persons or entities 196 responsible for authorship of the modifications in the Modified 197 Version, together with at least five of the principal authors of the 198 Document (all of its principal authors, if it has fewer than five), 199 unless they release you from this requirement. 200 201C. State on the Title page the name of the publisher of the 202 Modified Version, as the publisher. 203 204D. Preserve all the copyright notices of the Document. 205 206E. Add an appropriate copyright notice for your modifications 207 adjacent to the other copyright notices. 208 209F. Include, immediately after the copyright notices, a license notice 210 giving the public permission to use the Modified Version under the 211 terms of this License, in the form shown in the Addendum below. 212 213G. Preserve in that license notice the full lists of Invariant Sections 214 and required Cover Texts given in the Document's license notice. 215H. Include an unaltered copy of this License. 216 217I. Preserve the section Entitled "History", Preserve its Title, and add 218 to it an item stating at least the title, year, new authors, and 219 publisher of the Modified Version as given on the Title Page. If 220 there is no section Entitled "History" in the Document, create one 221 stating the title, year, authors, and publisher of the Document as 222 given on its Title Page, then add an item describing the Modified 223 Version as stated in the previous sentence. 224 225J. Preserve the network location, if any, given in the Document for 226 public access to a Transparent copy of the Document, and likewise 227 the network locations given in the Document for previous versions 228 it was based on. These may be placed in the "History" section. 229 You may omit a network location for a work that was published at 230 least four years before the Document itself, or if the original 231 publisher of the version it refers to gives permission. 232 233K. For any section Entitled "Acknowledgements" or "Dedications", 234 Preserve the Title of the section, and preserve in the section all 235 the substance and tone of each of the contributor acknowledgements 236 and/or dedications given therein. 237 238L. Preserve all the Invariant Sections of the Document, 239 unaltered in their text and in their titles. Section numbers 240 or the equivalent are not considered part of the section titles. 241 242M. Delete any section Entitled "Endorsements". Such a section 243 may not be included in the Modified Version. 244 245N. Do not retitle any existing section to be Entitled "Endorsements" 246 or to conflict in title with any Invariant Section. 247 248O. Preserve any Warranty Disclaimers. 249 250If the Modified Version includes new front-matter sections or 251appendices that qualify as Secondary Sections and contain no material 252copied from the Document, you may at your option designate some or all 253of these sections as invariant. To do this, add their titles to the 254list of Invariant Sections in the Modified Version's license notice. 255These titles must be distinct from any other section titles. 256 257You may add a section Entitled "Endorsements", provided it contains 258nothing but endorsements of your Modified Version by various 259parties---for example, statements of peer review or that the text has 260been approved by an organization as the authoritative definition of a 261standard. 262 263You may add a passage of up to five words as a Front-Cover Text, and a 264passage of up to 25 words as a Back-Cover Text, to the end of the list 265of Cover Texts in the Modified Version. Only one passage of 266Front-Cover Text and one of Back-Cover Text may be added by (or 267through arrangements made by) any one entity. If the Document already 268includes a cover text for the same cover, previously added by you or 269by arrangement made by the same entity you are acting on behalf of, 270you may not add another; but you may replace the old one, on explicit 271permission from the previous publisher that added the old one. 272 273The author(s) and publisher(s) of the Document do not by this License 274give permission to use their names for publicity for or to assert or 275imply endorsement of any Modified Version. 276 277**5. COMBINING DOCUMENTS** 278 279You may combine the Document with other documents released under this 280License, under the terms defined in section 4 above for modified 281versions, provided that you include in the combination all of the 282Invariant Sections of all of the original documents, unmodified, and 283list them all as Invariant Sections of your combined work in its 284license notice, and that you preserve all their Warranty Disclaimers. 285 286The combined work need only contain one copy of this License, and 287multiple identical Invariant Sections may be replaced with a single 288copy. If there are multiple Invariant Sections with the same name but 289different contents, make the title of each such section unique by 290adding at the end of it, in parentheses, the name of the original 291author or publisher of that section if known, or else a unique number. 292Make the same adjustment to the section titles in the list of 293Invariant Sections in the license notice of the combined work. 294 295In the combination, you must combine any sections Entitled "History" 296in the various original documents, forming one section Entitled 297"History"; likewise combine any sections Entitled "Acknowledgements", 298and any sections Entitled "Dedications". You must delete all sections 299Entitled "Endorsements". 300 301**6. COLLECTIONS OF DOCUMENTS** 302 303You may make a collection consisting of the Document and other documents 304released under this License, and replace the individual copies of this 305License in the various documents with a single copy that is included in 306the collection, provided that you follow the rules of this License for 307verbatim copying of each of the documents in all other respects. 308 309You may extract a single document from such a collection, and distribute 310it individually under this License, provided you insert a copy of this 311License into the extracted document, and follow this License in all 312other respects regarding verbatim copying of that document. 313 314**7. AGGREGATION WITH INDEPENDENT WORKS** 315 316A compilation of the Document or its derivatives with other separate 317and independent documents or works, in or on a volume of a storage or 318distribution medium, is called an "aggregate" if the copyright 319resulting from the compilation is not used to limit the legal rights 320of the compilation's users beyond what the individual works permit. 321When the Document is included in an aggregate, this License does not 322apply to the other works in the aggregate which are not themselves 323derivative works of the Document. 324 325If the Cover Text requirement of section 3 is applicable to these 326copies of the Document, then if the Document is less than one half of 327the entire aggregate, the Document's Cover Texts may be placed on 328covers that bracket the Document within the aggregate, or the 329electronic equivalent of covers if the Document is in electronic form. 330Otherwise they must appear on printed covers that bracket the whole 331aggregate. 332 333**8. TRANSLATION** 334 335Translation is considered a kind of modification, so you may 336distribute translations of the Document under the terms of section 4. 337Replacing Invariant Sections with translations requires special 338permission from their copyright holders, but you may include 339translations of some or all Invariant Sections in addition to the 340original versions of these Invariant Sections. You may include a 341translation of this License, and all the license notices in the 342Document, and any Warranty Disclaimers, provided that you also include 343the original English version of this License and the original versions 344of those notices and disclaimers. In case of a disagreement between 345the translation and the original version of this License or a notice 346or disclaimer, the original version will prevail. 347 348If a section in the Document is Entitled "Acknowledgements", 349"Dedications", or "History", the requirement (section 4) to Preserve 350its Title (section 1) will typically require changing the actual 351title. 352 353**9. TERMINATION** 354 355You may not copy, modify, sublicense, or distribute the Document 356except as expressly provided under this License. Any attempt 357otherwise to copy, modify, sublicense, or distribute it is void, and 358will automatically terminate your rights under this License. 359 360However, if you cease all violation of this License, then your license 361from a particular copyright holder is reinstated (a) provisionally, 362unless and until the copyright holder explicitly and finally 363terminates your license, and (b) permanently, if the copyright holder 364fails to notify you of the violation by some reasonable means prior to 36560 days after the cessation. 366 367Moreover, your license from a particular copyright holder is 368reinstated permanently if the copyright holder notifies you of the 369violation by some reasonable means, this is the first time you have 370received notice of violation of this License (for any work) from that 371copyright holder, and you cure the violation prior to 30 days after 372your receipt of the notice. 373 374Termination of your rights under this section does not terminate the 375licenses of parties who have received copies or rights from you under 376this License. If your rights have been terminated and not permanently 377reinstated, receipt of a copy of some or all of the same material does 378not give you any rights to use it. 379 380**10. FUTURE REVISIONS OF THIS LICENSE** 381 382The Free Software Foundation may publish new, revised versions 383of the GNU Free Documentation License from time to time. Such new 384versions will be similar in spirit to the present version, but may 385differ in detail to address new problems or concerns. See 386http://www.gnu.org/copyleft/. 387 388Each version of the License is given a distinguishing version number. 389If the Document specifies that a particular numbered version of this 390License "or any later version" applies to it, you have the option of 391following the terms and conditions either of that specified version or 392of any later version that has been published (not as a draft) by the 393Free Software Foundation. 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Texts." line with this: 447 448 with the Invariant Sections being LIST THEIR TITLES, with the 449 Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. 450 451If you have Invariant Sections without Cover Texts, or some other 452combination of the three, merge those two alternatives to suit the 453situation. 454 455If your document contains nontrivial examples of program code, we 456recommend releasing these examples in parallel under your choice of 457free software license, such as the GNU General Public License, 458to permit their use in free software. 459