1@c The GNU Lesser General Public License. 2@center Version 2.1, February 1999 3 4@c This file is intended to be included within another document, 5@c hence no sectioning command or @node. 6 7@display 8Copyright @copyright{} 1991, 1999 Free Software Foundation, Inc. 951 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA 10 11Everyone is permitted to copy and distribute verbatim copies 12of this license document, but changing it is not allowed. 13 14[This is the first released version of the Lesser GPL. It also counts 15as the successor of the GNU Library Public License, version 2, hence the 16version number 2.1.] 17@end display 18 19@subheading Preamble 20 21 The licenses for most software are designed to take away your 22freedom to share and change it. By contrast, the GNU General Public 23Licenses are intended to guarantee your freedom to share and change 24free software---to make sure the software is free for all its users. 25 26 This license, the Lesser General Public License, applies to some 27specially designated software---typically libraries---of the Free 28Software Foundation and other authors who decide to use it. You can use 29it too, but we suggest you first think carefully about whether this 30license or the ordinary General Public License is the better strategy to 31use in any particular case, based on the explanations below. 32 33 When we speak of free software, we are referring to freedom of use, 34not price. Our General Public Licenses are designed to make sure that 35you have the freedom to distribute copies of free software (and charge 36for this service if you wish); that you receive source code or can get 37it if you want it; that you can change the software and use pieces of it 38in new free programs; and that you are informed that you can do these 39things. 40 41 To protect your rights, we need to make restrictions that forbid 42distributors to deny you these rights or to ask you to surrender these 43rights. These restrictions translate to certain responsibilities for 44you if you distribute copies of the library or if you modify it. 45 46 For example, if you distribute copies of the library, whether gratis 47or for a fee, you must give the recipients all the rights that we gave 48you. You must make sure that they, too, receive or can get the source 49code. If you link other code with the library, you must provide 50complete object files to the recipients, so that they can relink them 51with the library after making changes to the library and recompiling 52it. And you must show them these terms so they know their rights. 53 54 We protect your rights with a two-step method: (1) we copyright the 55library, and (2) we offer you this license, which gives you legal 56permission to copy, distribute and/or modify the library. 57 58 To protect each distributor, we want to make it very clear that 59there is no warranty for the free library. Also, if the library is 60modified by someone else and passed on, the recipients should know 61that what they have is not the original version, so that the original 62author's reputation will not be affected by problems that might be 63introduced by others. 64 65 Finally, software patents pose a constant threat to the existence of 66any free program. We wish to make sure that a company cannot 67effectively restrict the users of a free program by obtaining a 68restrictive license from a patent holder. Therefore, we insist that 69any patent license obtained for a version of the library must be 70consistent with the full freedom of use specified in this license. 71 72 Most GNU software, including some libraries, is covered by the 73ordinary GNU General Public License. This license, the GNU Lesser 74General Public License, applies to certain designated libraries, and 75is quite different from the ordinary General Public License. We use 76this license for certain libraries in order to permit linking those 77libraries into non-free programs. 78 79 When a program is linked with a library, whether statically or using 80a shared library, the combination of the two is legally speaking a 81combined work, a derivative of the original library. The ordinary 82General Public License therefore permits such linking only if the 83entire combination fits its criteria of freedom. The Lesser General 84Public License permits more lax criteria for linking other code with 85the library. 86 87 We call this license the @dfn{Lesser} General Public License because it 88does @emph{Less} to protect the user's freedom than the ordinary General 89Public License. It also provides other free software developers Less 90of an advantage over competing non-free programs. These disadvantages 91are the reason we use the ordinary General Public License for many 92libraries. However, the Lesser license provides advantages in certain 93special circumstances. 94 95 For example, on rare occasions, there may be a special need to 96encourage the widest possible use of a certain library, so that it becomes 97a de-facto standard. To achieve this, non-free programs must be 98allowed to use the library. A more frequent case is that a free 99library does the same job as widely used non-free libraries. In this 100case, there is little to gain by limiting the free library to free 101software only, so we use the Lesser General Public License. 102 103 In other cases, permission to use a particular library in non-free 104programs enables a greater number of people to use a large body of 105free software. For example, permission to use the GNU C Library in 106non-free programs enables many more people to use the whole GNU 107operating system, as well as its variant, the GNU/Linux operating 108system. 109 110 Although the Lesser General Public License is Less protective of the 111users' freedom, it does ensure that the user of a program that is 112linked with the Library has the freedom and the wherewithal to run 113that program using a modified version of the Library. 114 115 The precise terms and conditions for copying, distribution and 116modification follow. Pay close attention to the difference between a 117``work based on the library'' and a ``work that uses the library''. The 118former contains code derived from the library, whereas the latter must 119be combined with the library in order to run. 120 121@subheading TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION 122 123@enumerate 0 124@item 125This License Agreement applies to any software library or other program 126which contains a notice placed by the copyright holder or other 127authorized party saying it may be distributed under the terms of this 128Lesser General Public License (also called ``this License''). Each 129licensee is addressed as ``you''. 130 131 A ``library'' means a collection of software functions and/or data 132prepared so as to be conveniently linked with application programs 133(which use some of those functions and data) to form executables. 134 135 The ``Library'', below, refers to any such software library or work 136which has been distributed under these terms. A ``work based on the 137Library'' means either the Library or any derivative work under 138copyright law: that is to say, a work containing the Library or a 139portion of it, either verbatim or with modifications and/or translated 140straightforwardly into another language. (Hereinafter, translation is 141included without limitation in the term ``modification''.) 142 143 ``Source code'' for a work means the preferred form of the work for 144making modifications to it. For a library, complete source code means 145all the source code for all modules it contains, plus any associated 146interface definition files, plus the scripts used to control compilation 147and installation of the library. 148 149 Activities other than copying, distribution and modification are not 150covered by this License; they are outside its scope. The act of 151running a program using the Library is not restricted, and output from 152such a program is covered only if its contents constitute a work based 153on the Library (independent of the use of the Library in a tool for 154writing it). Whether that is true depends on what the Library does 155and what the program that uses the Library does. 156 157@item 158You may copy and distribute verbatim copies of the Library's 159complete source code as you receive it, in any medium, provided that 160you conspicuously and appropriately publish on each copy an 161appropriate copyright notice and disclaimer of warranty; keep intact 162all the notices that refer to this License and to the absence of any 163warranty; and distribute a copy of this License along with the 164Library. 165 166 You may charge a fee for the physical act of transferring a copy, 167and you may at your option offer warranty protection in exchange for a 168fee. 169 170@item 171You may modify your copy or copies of the Library or any portion 172of it, thus forming a work based on the Library, and copy and 173distribute such modifications or work under the terms of Section 1 174above, provided that you also meet all of these conditions: 175 176@enumerate a 177@item 178The modified work must itself be a software library. 179 180@item 181You must cause the files modified to carry prominent notices 182stating that you changed the files and the date of any change. 183 184@item 185You must cause the whole of the work to be licensed at no 186charge to all third parties under the terms of this License. 187 188@item 189If a facility in the modified Library refers to a function or a 190table of data to be supplied by an application program that uses 191the facility, other than as an argument passed when the facility 192is invoked, then you must make a good faith effort to ensure that, 193in the event an application does not supply such function or 194table, the facility still operates, and performs whatever part of 195its purpose remains meaningful. 196 197(For example, a function in a library to compute square roots has 198a purpose that is entirely well-defined independent of the 199application. Therefore, Subsection 2d requires that any 200application-supplied function or table used by this function must 201be optional: if the application does not supply it, the square 202root function must still compute square roots.) 203@end enumerate 204 205These requirements apply to the modified work as a whole. If 206identifiable sections of that work are not derived from the Library, 207and can be reasonably considered independent and separate works in 208themselves, then this License, and its terms, do not apply to those 209sections when you distribute them as separate works. But when you 210distribute the same sections as part of a whole which is a work based 211on the Library, the distribution of the whole must be on the terms of 212this License, whose permissions for other licensees extend to the 213entire whole, and thus to each and every part regardless of who wrote 214it. 215 216Thus, it is not the intent of this section to claim rights or contest 217your rights to work written entirely by you; rather, the intent is to 218exercise the right to control the distribution of derivative or 219collective works based on the Library. 220 221In addition, mere aggregation of another work not based on the Library 222with the Library (or with a work based on the Library) on a volume of 223a storage or distribution medium does not bring the other work under 224the scope of this License. 225 226@item 227You may opt to apply the terms of the ordinary GNU General Public 228License instead of this License to a given copy of the Library. To do 229this, you must alter all the notices that refer to this License, so 230that they refer to the ordinary GNU General Public License, version 2, 231instead of to this License. (If a newer version than version 2 of the 232ordinary GNU General Public License has appeared, then you can specify 233that version instead if you wish.) Do not make any other change in 234these notices. 235 236 Once this change is made in a given copy, it is irreversible for 237that copy, so the ordinary GNU General Public License applies to all 238subsequent copies and derivative works made from that copy. 239 240 This option is useful when you wish to copy part of the code of 241the Library into a program that is not a library. 242 243@item 244You may copy and distribute the Library (or a portion or 245derivative of it, under Section 2) in object code or executable form 246under the terms of Sections 1 and 2 above provided that you accompany 247it with the complete corresponding machine-readable source code, which 248must be distributed under the terms of Sections 1 and 2 above on a 249medium customarily used for software interchange. 250 251 If distribution of object code is made by offering access to copy 252from a designated place, then offering equivalent access to copy the 253source code from the same place satisfies the requirement to 254distribute the source code, even though third parties are not 255compelled to copy the source along with the object code. 256 257@item 258A program that contains no derivative of any portion of the 259Library, but is designed to work with the Library by being compiled or 260linked with it, is called a ``work that uses the Library''. Such a 261work, in isolation, is not a derivative work of the Library, and 262therefore falls outside the scope of this License. 263 264 However, linking a ``work that uses the Library'' with the Library 265creates an executable that is a derivative of the Library (because it 266contains portions of the Library), rather than a ``work that uses the 267library''. The executable is therefore covered by this License. 268Section 6 states terms for distribution of such executables. 269 270 When a ``work that uses the Library'' uses material from a header file 271that is part of the Library, the object code for the work may be a 272derivative work of the Library even though the source code is not. 273Whether this is true is especially significant if the work can be 274linked without the Library, or if the work is itself a library. The 275threshold for this to be true is not precisely defined by law. 276 277 If such an object file uses only numerical parameters, data 278structure layouts and accessors, and small macros and small inline 279functions (ten lines or less in length), then the use of the object 280file is unrestricted, regardless of whether it is legally a derivative 281work. (Executables containing this object code plus portions of the 282Library will still fall under Section 6.) 283 284 Otherwise, if the work is a derivative of the Library, you may 285distribute the object code for the work under the terms of Section 6. 286Any executables containing that work also fall under Section 6, 287whether or not they are linked directly with the Library itself. 288 289@item 290As an exception to the Sections above, you may also combine or 291link a ``work that uses the Library'' with the Library to produce a 292work containing portions of the Library, and distribute that work 293under terms of your choice, provided that the terms permit 294modification of the work for the customer's own use and reverse 295engineering for debugging such modifications. 296 297 You must give prominent notice with each copy of the work that the 298Library is used in it and that the Library and its use are covered by 299this License. You must supply a copy of this License. If the work 300during execution displays copyright notices, you must include the 301copyright notice for the Library among them, as well as a reference 302directing the user to the copy of this License. Also, you must do one 303of these things: 304 305@enumerate a 306@item 307Accompany the work with the complete corresponding 308machine-readable source code for the Library including whatever 309changes were used in the work (which must be distributed under 310Sections 1 and 2 above); and, if the work is an executable linked 311with the Library, with the complete machine-readable ``work that 312uses the Library'', as object code and/or source code, so that the 313user can modify the Library and then relink to produce a modified 314executable containing the modified Library. (It is understood 315that the user who changes the contents of definitions files in the 316Library will not necessarily be able to recompile the application 317to use the modified definitions.) 318 319@item 320Use a suitable shared library mechanism for linking with the Library. A 321suitable mechanism is one that (1) uses at run time a copy of the 322library already present on the user's computer system, rather than 323copying library functions into the executable, and (2) will operate 324properly with a modified version of the library, if the user installs 325one, as long as the modified version is interface-compatible with the 326version that the work was made with. 327 328@item 329Accompany the work with a written offer, valid for at 330least three years, to give the same user the materials 331specified in Subsection 6a, above, for a charge no more 332than the cost of performing this distribution. 333 334@item 335If distribution of the work is made by offering access to copy 336from a designated place, offer equivalent access to copy the above 337specified materials from the same place. 338 339@item 340Verify that the user has already received a copy of these 341materials or that you have already sent this user a copy. 342@end enumerate 343 344 For an executable, the required form of the ``work that uses the 345Library'' must include any data and utility programs needed for 346reproducing the executable from it. However, as a special exception, 347the materials to be distributed need not include anything that is 348normally distributed (in either source or binary form) with the major 349components (compiler, kernel, and so on) of the operating system on 350which the executable runs, unless that component itself accompanies the 351executable. 352 353 It may happen that this requirement contradicts the license 354restrictions of other proprietary libraries that do not normally 355accompany the operating system. Such a contradiction means you cannot 356use both them and the Library together in an executable that you 357distribute. 358 359@item 360You may place library facilities that are a work based on the 361Library side-by-side in a single library together with other library 362facilities not covered by this License, and distribute such a combined 363library, provided that the separate distribution of the work based on 364the Library and of the other library facilities is otherwise 365permitted, and provided that you do these two things: 366 367@enumerate a 368@item 369Accompany the combined library with a copy of the same work 370based on the Library, uncombined with any other library 371facilities. This must be distributed under the terms of the 372Sections above. 373 374@item 375Give prominent notice with the combined library of the fact 376that part of it is a work based on the Library, and explaining 377where to find the accompanying uncombined form of the same work. 378@end enumerate 379 380@item 381You may not copy, modify, sublicense, link with, or distribute 382the Library except as expressly provided under this License. Any 383attempt otherwise to copy, modify, sublicense, link with, or 384distribute the Library is void, and will automatically terminate your 385rights under this License. However, parties who have received copies, 386or rights, from you under this License will not have their licenses 387terminated so long as such parties remain in full compliance. 388 389@item 390You are not required to accept this License, since you have not 391signed it. However, nothing else grants you permission to modify or 392distribute the Library or its derivative works. These actions are 393prohibited by law if you do not accept this License. Therefore, by 394modifying or distributing the Library (or any work based on the 395Library), you indicate your acceptance of this License to do so, and 396all its terms and conditions for copying, distributing or modifying 397the Library or works based on it. 398 399@item 400Each time you redistribute the Library (or any work based on the 401Library), the recipient automatically receives a license from the 402original licensor to copy, distribute, link with or modify the Library 403subject to these terms and conditions. You may not impose any further 404restrictions on the recipients' exercise of the rights granted herein. 405You are not responsible for enforcing compliance by third parties with 406this License. 407 408@item 409If, as a consequence of a court judgment or allegation of patent 410infringement or for any other reason (not limited to patent issues), 411conditions are imposed on you (whether by court order, agreement or 412otherwise) that contradict the conditions of this License, they do not 413excuse you from the conditions of this License. If you cannot 414distribute so as to satisfy simultaneously your obligations under this 415License and any other pertinent obligations, then as a consequence you 416may not distribute the Library at all. For example, if a patent 417license would not permit royalty-free redistribution of the Library by 418all those who receive copies directly or indirectly through you, then 419the only way you could satisfy both it and this License would be to 420refrain entirely from distribution of the Library. 421 422If any portion of this section is held invalid or unenforceable under any 423particular circumstance, the balance of the section is intended to apply, 424and the section as a whole is intended to apply in other circumstances. 425 426It is not the purpose of this section to induce you to infringe any 427patents or other property right claims or to contest validity of any 428such claims; this section has the sole purpose of protecting the 429integrity of the free software distribution system which is 430implemented by public license practices. Many people have made 431generous contributions to the wide range of software distributed 432through that system in reliance on consistent application of that 433system; it is up to the author/donor to decide if he or she is willing 434to distribute software through any other system and a licensee cannot 435impose that choice. 436 437This section is intended to make thoroughly clear what is believed to 438be a consequence of the rest of this License. 439 440@item 441If the distribution and/or use of the Library is restricted in 442certain countries either by patents or by copyrighted interfaces, the 443original copyright holder who places the Library under this License may add 444an explicit geographical distribution limitation excluding those countries, 445so that distribution is permitted only in or among countries not thus 446excluded. In such case, this License incorporates the limitation as if 447written in the body of this License. 448 449@item 450The Free Software Foundation may publish revised and/or new 451versions of the Lesser General Public License from time to time. 452Such new versions will be similar in spirit to the present version, 453but may differ in detail to address new problems or concerns. 454 455Each version is given a distinguishing version number. If the Library 456specifies a version number of this License which applies to it and 457``any later version'', you have the option of following the terms and 458conditions either of that version or of any later version published by 459the Free Software Foundation. If the Library does not specify a 460license version number, you may choose any version ever published by 461the Free Software Foundation. 462 463@item 464If you wish to incorporate parts of the Library into other free 465programs whose distribution conditions are incompatible with these, 466write to the author to ask for permission. For software which is 467copyrighted by the Free Software Foundation, write to the Free 468Software Foundation; we sometimes make exceptions for this. Our 469decision will be guided by the two goals of preserving the free status 470of all derivatives of our free software and of promoting the sharing 471and reuse of software generally. 472 473@center @b{NO WARRANTY} 474 475@item 476BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NO 477WARRANTY FOR THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE LAW. 478EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR 479OTHER PARTIES PROVIDE THE LIBRARY ``AS IS'' WITHOUT WARRANTY OF ANY 480KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE 481IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 482PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE 483LIBRARY IS WITH YOU. SHOULD THE LIBRARY PROVE DEFECTIVE, YOU ASSUME 484THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 485 486@item 487IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN 488WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY 489AND/OR REDISTRIBUTE THE LIBRARY AS PERMITTED ABOVE, BE LIABLE TO YOU 490FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR 491CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE 492LIBRARY (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING 493RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A 494FAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF 495SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH 496DAMAGES. 497@end enumerate 498 499@subheading END OF TERMS AND CONDITIONS 500 501@page 502@subheading How to Apply These Terms to Your New Libraries 503 504 If you develop a new library, and you want it to be of the greatest 505possible use to the public, we recommend making it free software that 506everyone can redistribute and change. You can do so by permitting 507redistribution under these terms (or, alternatively, under the terms of the 508ordinary General Public License). 509 510 To apply these terms, attach the following notices to the library. It is 511safest to attach them to the start of each source file to most effectively 512convey the exclusion of warranty; and each file should have at least the 513``copyright'' line and a pointer to where the full notice is found. 514 515@smallexample 516@var{one line to give the library's name and an idea of what it does.} 517Copyright (C) @var{year} @var{name of author} 518 519This library is free software; you can redistribute it and/or modify it 520under the terms of the GNU Lesser General Public License as published by 521the Free Software Foundation; either version 2.1 of the License, or (at 522your option) any later version. 523 524This library is distributed in the hope that it will be useful, but 525WITHOUT ANY WARRANTY; without even the implied warranty of 526MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 527Lesser General Public License for more details. 528 529You should have received a copy of the GNU Lesser General Public 530License along with this library; if not, write to the Free Software 531Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 532USA. 533@end smallexample 534 535Also add information on how to contact you by electronic and paper mail. 536 537You should also get your employer (if you work as a programmer) or your 538school, if any, to sign a ``copyright disclaimer'' for the library, if 539necessary. Here is a sample; alter the names: 540 541@smallexample 542Yoyodyne, Inc., hereby disclaims all copyright interest in the library 543`Frob' (a library for tweaking knobs) written by James Random Hacker. 544 545@var{signature of Ty Coon}, 1 April 1990 546Ty Coon, President of Vice 547@end smallexample 548 549That's all there is to it! 550