1GNU LESSER GENERAL PUBLIC LICENSE 2 3Version 2.1, February 1999 4 5Copyright (C) 1991, 1999 Free Software Foundation, Inc. 6 751 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 8 9Everyone is permitted to copy and distribute verbatim copies of this license 10document, but changing it is not allowed. 11 12[This is the first released version of the Lesser GPL. It also counts as the 13successor of the GNU Library Public License, version 2, hence the version 14number 2.1.] 15 16Preamble 17 18The licenses for most software are designed to take away your freedom to share 19and change it. By contrast, the GNU General Public Licenses are intended to 20guarantee your freedom to share and change free software--to make sure the 21software is free for all its users. 22 23This license, the Lesser General Public License, applies to some specially 24designated software packages--typically libraries--of the Free Software Foundation 25and other authors who decide to use it. You can use it too, but we suggest 26you first think carefully about whether this license or the ordinary General 27Public License is the better strategy to use in any particular case, based 28on the explanations below. 29 30When we speak of free software, we are referring to freedom of use, not price. 31Our General Public Licenses are designed to make sure that you have the freedom 32to distribute copies of free software (and charge for this service if you 33wish); that you receive source code or can get it if you want it; that you 34can change the software and use pieces of it in new free programs; and that 35you are informed that you can do these things. 36 37To protect your rights, we need to make restrictions that forbid distributors 38to deny you these rights or to ask you to surrender these rights. These restrictions 39translate to certain responsibilities for you if you distribute copies of 40the library or if you modify it. 41 42For example, if you distribute copies of the library, whether gratis or for 43a fee, you must give the recipients all the rights that we gave you. You must 44make sure that they, too, receive or can get the source code. If you link 45other code with the library, you must provide complete object files to the 46recipients, so that they can relink them with the library after making changes 47to the library and recompiling it. And you must show them these terms so they 48know their rights. 49 50We protect your rights with a two-step method: (1) we copyright the library, 51and (2) we offer you this license, which gives you legal permission to copy, 52distribute and/or modify the library. 53 54To protect each distributor, we want to make it very clear that there is no 55warranty for the free library. Also, if the library is modified by someone 56else and passed on, the recipients should know that what they have is not 57the original version, so that the original author's reputation will not be 58affected by problems that might be introduced by others. 59 60Finally, software patents pose a constant threat to the existence of any free 61program. We wish to make sure that a company cannot effectively restrict the 62users of a free program by obtaining a restrictive license from a patent holder. 63Therefore, we insist that any patent license obtained for a version of the 64library must be consistent with the full freedom of use specified in this 65license. 66 67Most GNU software, including some libraries, is covered by the ordinary GNU 68General Public License. This license, the GNU Lesser General Public License, 69applies to certain designated libraries, and is quite different from the ordinary 70General Public License. We use this license for certain libraries in order 71to permit linking those libraries into non-free programs. 72 73When a program is linked with a library, whether statically or using a shared 74library, the combination of the two is legally speaking a combined work, a 75derivative of the original library. The ordinary General Public License therefore 76permits such linking only if the entire combination fits its criteria of freedom. 77The Lesser General Public License permits more lax criteria for linking other 78code with the library. 79 80We call this license the "Lesser" General Public License because it does Less 81to protect the user's freedom than the ordinary General Public License. It 82also provides other free software developers Less of an advantage over competing 83non-free programs. These disadvantages are the reason we use the ordinary 84General Public License for many libraries. However, the Lesser license provides 85advantages in certain special circumstances. 86 87For example, on rare occasions, there may be a special need to encourage the 88widest possible use of a certain library, so that it becomes a de-facto standard. 89To achieve this, non-free programs must be allowed to use the library. A more 90frequent case is that a free library does the same job as widely used non-free 91libraries. In this case, there is little to gain by limiting the free library 92to free software only, so we use the Lesser General Public License. 93 94In other cases, permission to use a particular library in non-free programs 95enables a greater number of people to use a large body of free software. For 96example, permission to use the GNU C Library in non-free programs enables 97many more people to use the whole GNU operating system, as well as its variant, 98the GNU/Linux operating system. 99 100Although the Lesser General Public License is Less protective of the users' 101freedom, it does ensure that the user of a program that is linked with the 102Library has the freedom and the wherewithal to run that program using a modified 103version of the Library. 104 105The precise terms and conditions for copying, distribution and modification 106follow. Pay close attention to the difference between a "work based on the 107library" and a "work that uses the library". The former contains code derived 108from the library, whereas the latter must be combined with the library in 109order to run. 110 111TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION 112 1130. This License Agreement applies to any software library or other program 114which contains a notice placed by the copyright holder or other authorized 115party saying it may be distributed under the terms of this Lesser General 116Public License (also called "this License"). Each licensee is addressed as 117"you". 118 119A "library" means a collection of software functions and/or data prepared 120so as to be conveniently linked with application programs (which use some 121of those functions and data) to form executables. 122 123The "Library", below, refers to any such software library or work which has 124been distributed under these terms. A "work based on the Library" means either 125the Library or any derivative work under copyright law: that is to say, a 126work containing the Library or a portion of it, either verbatim or with modifications 127and/or translated straightforwardly into another language. (Hereinafter, translation 128is included without limitation in the term "modification".) 129 130"Source code" for a work means the preferred form of the work for making modifications 131to it. For a library, complete source code means all the source code for all 132modules it contains, plus any associated interface definition files, plus 133the scripts used to control compilation and installation of the library. 134 135Activities other than copying, distribution and modification are not covered 136by this License; they are outside its scope. The act of running a program 137using the Library is not restricted, and output from such a program is covered 138only if its contents constitute a work based on the Library (independent of 139the use of the Library in a tool for writing it). Whether that is true depends 140on what the Library does and what the program that uses the Library does. 141 1421. You may copy and distribute verbatim copies of the Library's complete source 143code as you receive it, in any medium, provided that you conspicuously and 144appropriately publish on each copy an appropriate copyright notice and disclaimer 145of warranty; keep intact all the notices that refer to this License and to 146the absence of any warranty; and distribute a copy of this License along with 147the Library. 148 149You may charge a fee for the physical act of transferring a copy, and you 150may at your option offer warranty protection in exchange for a fee. 151 1522. You may modify your copy or copies of the Library or any portion of it, 153thus forming a work based on the Library, and copy and distribute such modifications 154or work under the terms of Section 1 above, provided that you also meet all 155of these conditions: 156 157 a) The modified work must itself be a software library. 158 159b) You must cause the files modified to carry prominent notices stating that 160you changed the files and the date of any change. 161 162c) You must cause the whole of the work to be licensed at no charge to all 163third parties under the terms of this License. 164 165d) If a facility in the modified Library refers to a function or a table of 166data to be supplied by an application program that uses the facility, other 167than as an argument passed when the facility is invoked, then you must make 168a good faith effort to ensure that, in the event an application does not supply 169such function or table, the facility still operates, and performs whatever 170part of its purpose remains meaningful. 171 172(For example, a function in a library to compute square roots has a purpose 173that is entirely well-defined independent of the application. Therefore, Subsection 1742d requires that any application-supplied function or table used by this function 175must be optional: if the application does not supply it, the square root function 176must still compute square roots.) 177 178These requirements apply to the modified work as a whole. If identifiable 179sections of that work are not derived from the Library, and can be reasonably 180considered independent and separate works in themselves, then this License, 181and its terms, do not apply to those sections when you distribute them as 182separate works. But when you distribute the same sections as part of a whole 183which is a work based on the Library, the distribution of the whole must be 184on the terms of this License, whose permissions for other licensees extend 185to the entire whole, and thus to each and every part regardless of who wrote 186it. 187 188Thus, it is not the intent of this section to claim rights or contest your 189rights to work written entirely by you; rather, the intent is to exercise 190the right to control the distribution of derivative or collective works based 191on the Library. 192 193In addition, mere aggregation of another work not based on the Library with 194the Library (or with a work based on the Library) on a volume of a storage 195or distribution medium does not bring the other work under the scope of this 196License. 197 1983. You may opt to apply the terms of the ordinary GNU General Public License 199instead of this License to a given copy of the Library. To do this, you must 200alter all the notices that refer to this License, so that they refer to the 201ordinary GNU General Public License, version 2, instead of to this License. 202(If a newer version than version 2 of the ordinary GNU General Public License 203has appeared, then you can specify that version instead if you wish.) Do not 204make any other change in these notices. 205 206Once this change is made in a given copy, it is irreversible for that copy, 207so the ordinary GNU General Public License applies to all subsequent copies 208and derivative works made from that copy. 209 210This option is useful when you wish to copy part of the code of the Library 211into a program that is not a library. 212 2134. You may copy and distribute the Library (or a portion or derivative of 214it, under Section 2) in object code or executable form under the terms of 215Sections 1 and 2 above provided that you accompany it with the complete corresponding 216machine-readable source code, which must be distributed under the terms of 217Sections 1 and 2 above on a medium customarily used for software interchange. 218 219If distribution of object code is made by offering access to copy from a designated 220place, then offering equivalent access to copy the source code from the same 221place satisfies the requirement to distribute the source code, even though 222third parties are not compelled to copy the source along with the object code. 223 2245. A program that contains no derivative of any portion of the Library, but 225is designed to work with the Library by being compiled or linked with it, 226is called a "work that uses the Library". Such a work, in isolation, is not 227a derivative work of the Library, and therefore falls outside the scope of 228this License. 229 230However, linking a "work that uses the Library" with the Library creates an 231executable that is a derivative of the Library (because it contains portions 232of the Library), rather than a "work that uses the library". The executable 233is therefore covered by this License. Section 6 states terms for distribution 234of such executables. 235 236When a "work that uses the Library" uses material from a header file that 237is part of the Library, the object code for the work may be a derivative work 238of the Library even though the source code is not. Whether this is true is 239especially significant if the work can be linked without the Library, or if 240the work is itself a library. The threshold for this to be true is not precisely 241defined by law. 242 243If such an object file uses only numerical parameters, data structure layouts 244and accessors, and small macros and small inline functions (ten lines or less 245in length), then the use of the object file is unrestricted, regardless of 246whether it is legally a derivative work. (Executables containing this object 247code plus portions of the Library will still fall under Section 6.) 248 249Otherwise, if the work is a derivative of the Library, you may distribute 250the object code for the work under the terms of Section 6. Any executables 251containing that work also fall under Section 6, whether or not they are linked 252directly with the Library itself. 253 2546. As an exception to the Sections above, you may also combine or link a "work 255that uses the Library" with the Library to produce a work containing portions 256of the Library, and distribute that work under terms of your choice, provided 257that the terms permit modification of the work for the customer's own use 258and reverse engineering for debugging such modifications. 259 260You must give prominent notice with each copy of the work that the Library 261is used in it and that the Library and its use are covered by this License. 262You must supply a copy of this License. If the work during execution displays 263copyright notices, you must include the copyright notice for the Library among 264them, as well as a reference directing the user to the copy of this License. 265Also, you must do one of these things: 266 267a) Accompany the work with the complete corresponding machine-readable source 268code for the Library including whatever changes were used in the work (which 269must be distributed under Sections 1 and 2 above); and, if the work is an 270executable linked with the Library, with the complete machine-readable "work 271that uses the Library", as object code and/or source code, so that the user 272can modify the Library and then relink to produce a modified executable containing 273the modified Library. (It is understood that the user who changes the contents 274of definitions files in the Library will not necessarily be able to recompile 275the application to use the modified definitions.) 276 277b) Use a suitable shared library mechanism for linking with the Library. A 278suitable mechanism is one that (1) uses at run time a copy of the library 279already present on the user's computer system, rather than copying library 280functions into the executable, and (2) will operate properly with a modified 281version of the library, if the user installs one, as long as the modified 282version is interface-compatible with the version that the work was made with. 283 284c) Accompany the work with a written offer, valid for at least three years, 285to give the same user the materials specified in Subsection 6a, above, for 286a charge no more than the cost of performing this distribution. 287 288d) If distribution of the work is made by offering access to copy from a designated 289place, offer equivalent access to copy the above specified materials from 290the same place. 291 292e) Verify that the user has already received a copy of these materials or 293that you have already sent this user a copy. 294 295For an executable, the required form of the "work that uses the Library" must 296include any data and utility programs needed for reproducing the executable 297from it. However, as a special exception, the materials to be distributed 298need not include anything that is normally distributed (in either source or 299binary form) with the major components (compiler, kernel, and so on) of the 300operating system on which the executable runs, unless that component itself 301accompanies the executable. 302 303It may happen that this requirement contradicts the license restrictions of 304other proprietary libraries that do not normally accompany the operating system. 305Such a contradiction means you cannot use both them and the Library together 306in an executable that you distribute. 307 3087. You may place library facilities that are a work based on the Library side-by-side 309in a single library together with other library facilities not covered by 310this License, and distribute such a combined library, provided that the separate 311distribution of the work based on the Library and of the other library facilities 312is otherwise permitted, and provided that you do these two things: 313 314a) Accompany the combined library with a copy of the same work based on the 315Library, uncombined with any other library facilities. This must be distributed 316under the terms of the Sections above. 317 318b) Give prominent notice with the combined library of the fact that part of 319it is a work based on the Library, and explaining where to find the accompanying 320uncombined form of the same work. 321 3228. You may not copy, modify, sublicense, link with, or distribute the Library 323except as expressly provided under this License. Any attempt otherwise to 324copy, modify, sublicense, link with, or distribute the Library is void, and 325will automatically terminate your rights under this License. However, parties 326who have received copies, or rights, from you under this License will not 327have their licenses terminated so long as such parties remain in full compliance. 328 3299. You are not required to accept this License, since you have not signed 330it. However, nothing else grants you permission to modify or distribute the 331Library or its derivative works. These actions are prohibited by law if you 332do not accept this License. Therefore, by modifying or distributing the Library 333(or any work based on the Library), you indicate your acceptance of this License 334to do so, and all its terms and conditions for copying, distributing or modifying 335the Library or works based on it. 336 33710. Each time you redistribute the Library (or any work based on the Library), 338the recipient automatically receives a license from the original licensor 339to copy, distribute, link with or modify the Library subject to these terms 340and conditions. You may not impose any further restrictions on the recipients' 341exercise of the rights granted herein. You are not responsible for enforcing 342compliance by third parties with this License. 343 34411. If, as a consequence of a court judgment or allegation of patent infringement 345or for any other reason (not limited to patent issues), conditions are imposed 346on you (whether by court order, agreement or otherwise) that contradict the 347conditions of this License, they do not excuse you from the conditions of 348this License. If you cannot distribute so as to satisfy simultaneously your 349obligations under this License and any other pertinent obligations, then as 350a consequence you may not distribute the Library at all. For example, if a 351patent license would not permit royalty-free redistribution of the Library 352by all those who receive copies directly or indirectly through you, then the 353only way you could satisfy both it and this License would be to refrain entirely 354from distribution of the Library. 355 356If any portion of this section is held invalid or unenforceable under any 357particular circumstance, the balance of the section is intended to apply, 358and the section as a whole is intended to apply in other circumstances. 359 360It is not the purpose of this section to induce you to infringe any patents 361or other property right claims or to contest validity of any such claims; 362this section has the sole purpose of protecting the integrity of the free 363software distribution system which is implemented by public license practices. 364Many people have made generous contributions to the wide range of software 365distributed through that system in reliance on consistent application of that 366system; it is up to the author/donor to decide if he or she is willing to 367distribute software through any other system and a licensee cannot impose 368that choice. 369 370This section is intended to make thoroughly clear what is believed to be a 371consequence of the rest of this License. 372 37312. If the distribution and/or use of the Library is restricted in certain 374countries either by patents or by copyrighted interfaces, the original copyright 375holder who places the Library under this License may add an explicit geographical 376distribution limitation excluding those countries, so that distribution is 377permitted only in or among countries not thus excluded. In such case, this 378License incorporates the limitation as if written in the body of this License. 379 38013. The Free Software Foundation may publish revised and/or new versions of 381the Lesser General Public License from time to time. Such new versions will 382be similar in spirit to the present version, but may differ in detail to address 383new problems or concerns. 384 385Each version is given a distinguishing version number. If the Library specifies 386a version number of this License which applies to it and "any later version", 387you have the option of following the terms and conditions either of that version 388or of any later version published by the Free Software Foundation. If the 389Library does not specify a license version number, you may choose any version 390ever published by the Free Software Foundation. 391 39214. If you wish to incorporate parts of the Library into other free programs 393whose distribution conditions are incompatible with these, write to the author 394to ask for permission. For software which is copyrighted by the Free Software 395Foundation, write to the Free Software Foundation; we sometimes make exceptions 396for this. Our decision will be guided by the two goals of preserving the free 397status of all derivatives of our free software and of promoting the sharing 398and reuse of software generally. 399 400 NO WARRANTY 401 40215. BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR 403THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE 404STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE LIBRARY 405"AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, 406BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 407FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE 408OF THE LIBRARY IS WITH YOU. SHOULD THE LIBRARY PROVE DEFECTIVE, YOU ASSUME 409THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 410 41116. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 412WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE 413THE LIBRARY AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 414GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE 415OR INABILITY TO USE THE LIBRARY (INCLUDING BUT NOT LIMITED TO LOSS OF DATA 416OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES 417OR A FAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH 418HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. 419END OF TERMS AND CONDITIONS 420 421How to Apply These Terms to Your New Libraries 422 423If you develop a new library, and you want it to be of the greatest possible 424use to the public, we recommend making it free software that everyone can 425redistribute and change. You can do so by permitting redistribution under 426these terms (or, alternatively, under the terms of the ordinary General Public 427License). 428 429To apply these terms, attach the following notices to the library. It is safest 430to attach them to the start of each source file to most effectively convey 431the exclusion of warranty; and each file should have at least the "copyright" 432line and a pointer to where the full notice is found. 433 434<one line to give the library's name and an idea of what it does.> 435 436Copyright (C) <year> <name of author> 437 438This library is free software; you can redistribute it and/or modify it under 439the terms of the GNU Lesser General Public License as published by the Free 440Software Foundation; either version 2.1 of the License, or (at your option) 441any later version. 442 443This library is distributed in the hope that it will be useful, but WITHOUT 444ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 445FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more 446details. 447 448You should have received a copy of the GNU Lesser General Public License along 449with this library; if not, write to the Free Software Foundation, Inc., 51 450Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 451 452Also add information on how to contact you by electronic and paper mail. 453 454You should also get your employer (if you work as a programmer) or your school, 455if any, to sign a "copyright disclaimer" for the library, if necessary. Here 456is a sample; alter the names: 457 458Yoyodyne, Inc., hereby disclaims all copyright interest in 459 460the library `Frob' (a library for tweaking knobs) written 461 462by James Random Hacker. 463 464< signature of Ty Coon > , 1 April 1990 465 466Ty Coon, President of Vice 467 468That's all there is to it! 469