1 GNU LESSER GENERAL PUBLIC LICENSE 2 Version 2.1, February 1999 3 4 Copyright (C) 1991, 1999 Free Software Foundation, Inc. 5 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 6 Everyone is permitted to copy and distribute verbatim copies 7 of this license document, but changing it is not allowed. 8 9[This is the first released version of the Lesser GPL. It also counts 10 as the successor of the GNU Library Public License, version 2, hence 11 the version number 2.1.] 12 13 Preamble 14 15 The licenses for most software are designed to take away your 16freedom to share and change it. By contrast, the GNU General Public 17Licenses are intended to guarantee your freedom to share and change 18free software--to make sure the software is free for all its users. 19 20 This license, the Lesser General Public License, applies to some 21specially designated software packages--typically libraries--of the 22Free Software Foundation and other authors who decide to use it. You 23can use it too, but we suggest you first think carefully about whether 24this license or the ordinary General Public License is the better 25strategy to use in any particular case, based on the explanations below. 26 27 When we speak of free software, we are referring to freedom of use, 28not price. Our General Public Licenses are designed to make sure that 29you have the freedom to distribute copies of free software (and charge 30for this service if you wish); that you receive source code or can get 31it if you want it; that you can change the software and use pieces of 32it in new free programs; and that you are informed that you can do 33these things. 34 35 To protect your rights, we need to make restrictions that forbid 36distributors to deny you these rights or to ask you to surrender these 37rights. These restrictions translate to certain responsibilities for 38you if you distribute copies of the library or if you modify it. 39 40 For example, if you distribute copies of the library, whether gratis 41or for a fee, you must give the recipients all the rights that we gave 42you. You must make sure that they, too, receive or can get the source 43code. If you link other code with the library, you must provide 44complete object files to the recipients, so that they can relink them 45with the library after making changes to the library and recompiling 46it. And you must show them these terms so they know their rights. 47 48 We protect your rights with a two-step method: (1) we copyright the 49library, and (2) we offer you this license, which gives you legal 50permission to copy, distribute and/or modify the library. 51 52 To protect each distributor, we want to make it very clear that 53there is no warranty for the free library. Also, if the library is 54modified by someone else and passed on, the recipients should know 55that what they have is not the original version, so that the original 56author's reputation will not be affected by problems that might be 57introduced by others. 58 59 Finally, software patents pose a constant threat to the existence of 60any free program. We wish to make sure that a company cannot 61effectively restrict the users of a free program by obtaining a 62restrictive license from a patent holder. Therefore, we insist that 63any patent license obtained for a version of the library must be 64consistent with the full freedom of use specified in this license. 65 66 Most GNU software, including some libraries, is covered by the 67ordinary GNU General Public License. This license, the GNU Lesser 68General Public License, applies to certain designated libraries, and 69is quite different from the ordinary General Public License. We use 70this license for certain libraries in order to permit linking those 71libraries into non-free programs. 72 73 When a program is linked with a library, whether statically or using 74a shared library, the combination of the two is legally speaking a 75combined work, a derivative of the original library. The ordinary 76General Public License therefore permits such linking only if the 77entire combination fits its criteria of freedom. The Lesser General 78Public License permits more lax criteria for linking other code with 79the library. 80 81 We call this license the "Lesser" General Public License because it 82does Less to protect the user's freedom than the ordinary General 83Public License. It also provides other free software developers Less 84of an advantage over competing non-free programs. These disadvantages 85are the reason we use the ordinary General Public License for many 86libraries. However, the Lesser license provides advantages in certain 87special circumstances. 88 89 For example, on rare occasions, there may be a special need to 90encourage the widest possible use of a certain library, so that it becomes 91a de-facto standard. To achieve this, non-free programs must be 92allowed to use the library. A more frequent case is that a free 93library does the same job as widely used non-free libraries. In this 94case, there is little to gain by limiting the free library to free 95software only, so we use the Lesser General Public License. 96 97 In other cases, permission to use a particular library in non-free 98programs enables a greater number of people to use a large body of 99free software. For example, permission to use the GNU C Library in 100non-free programs enables many more people to use the whole GNU 101operating system, as well as its variant, the GNU/Linux operating 102system. 103 104 Although the Lesser General Public License is Less protective of the 105users' freedom, it does ensure that the user of a program that is 106linked with the Library has the freedom and the wherewithal to run 107that program using a modified version of the Library. 108 109 The precise terms and conditions for copying, distribution and 110modification follow. Pay close attention to the difference between a 111"work based on the library" and a "work that uses the library". The 112former contains code derived from the library, whereas the latter must 113be combined with the library in order to run. 114 115 TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION 116 117 0. This License Agreement applies to any software library or other 118program which contains a notice placed by the copyright holder or 119other authorized party saying it may be distributed under the terms of 120this Lesser General Public License (also called "this License"). 121Each licensee is addressed as "you". 122 123 A "library" means a collection of software functions and/or data 124prepared so as to be conveniently linked with application programs 125(which use some of those functions and data) to form executables. 126 127 The "Library", below, refers to any such software library or work 128which has been distributed under these terms. A "work based on the 129Library" means either the Library or any derivative work under 130copyright law: that is to say, a work containing the Library or a 131portion of it, either verbatim or with modifications and/or translated 132straightforwardly into another language. (Hereinafter, translation is 133included without limitation in the term "modification".) 134 135 "Source code" for a work means the preferred form of the work for 136making modifications to it. For a library, complete source code means 137all the source code for all modules it contains, plus any associated 138interface definition files, plus the scripts used to control compilation 139and installation of the library. 140 141 Activities other than copying, distribution and modification are not 142covered by this License; they are outside its scope. The act of 143running a program using the Library is not restricted, and output from 144such a program is covered only if its contents constitute a work based 145on the Library (independent of the use of the Library in a tool for 146writing it). Whether that is true depends on what the Library does 147and what the program that uses the Library does. 148 149 1. You may copy and distribute verbatim copies of the Library's 150complete source code as you receive it, in any medium, provided that 151you conspicuously and appropriately publish on each copy an 152appropriate copyright notice and disclaimer of warranty; keep intact 153all the notices that refer to this License and to the absence of any 154warranty; and distribute a copy of this License along with the 155Library. 156 157 You may charge a fee for the physical act of transferring a copy, 158and you may at your option offer warranty protection in exchange for a 159fee. 160 161 2. You may modify your copy or copies of the Library or any portion 162of it, thus forming a work based on the Library, and copy and 163distribute such modifications or work under the terms of Section 1 164above, provided that you also meet all of these conditions: 165 166 a) The modified work must itself be a software library. 167 168 b) You must cause the files modified to carry prominent notices 169 stating that you changed the files and the date of any change. 170 171 c) You must cause the whole of the work to be licensed at no 172 charge to all third parties under the terms of this License. 173 174 d) If a facility in the modified Library refers to a function or a 175 table of data to be supplied by an application program that uses 176 the facility, other than as an argument passed when the facility 177 is invoked, then you must make a good faith effort to ensure that, 178 in the event an application does not supply such function or 179 table, the facility still operates, and performs whatever part of 180 its purpose remains meaningful. 181 182 (For example, a function in a library to compute square roots has 183 a purpose that is entirely well-defined independent of the 184 application. Therefore, Subsection 2d requires that any 185 application-supplied function or table used by this function must 186 be optional: if the application does not supply it, the square 187 root function must still compute square roots.) 188 189These requirements apply to the modified work as a whole. If 190identifiable sections of that work are not derived from the Library, 191and can be reasonably considered independent and separate works in 192themselves, then this License, and its terms, do not apply to those 193sections when you distribute them as separate works. But when you 194distribute the same sections as part of a whole which is a work based 195on the Library, the distribution of the whole must be on the terms of 196this License, whose permissions for other licensees extend to the 197entire whole, and thus to each and every part regardless of who wrote 198it. 199 200Thus, it is not the intent of this section to claim rights or contest 201your rights to work written entirely by you; rather, the intent is to 202exercise the right to control the distribution of derivative or 203collective works based on the Library. 204 205In addition, mere aggregation of another work not based on the Library 206with the Library (or with a work based on the Library) on a volume of 207a storage or distribution medium does not bring the other work under 208the scope of this License. 209 210 3. You may opt to apply the terms of the ordinary GNU General Public 211License instead of this License to a given copy of the Library. To do 212this, you must alter all the notices that refer to this License, so 213that they refer to the ordinary GNU General Public License, version 2, 214instead of to this License. (If a newer version than version 2 of the 215ordinary GNU General Public License has appeared, then you can specify 216that version instead if you wish.) Do not make any other change in 217these notices. 218 219 Once this change is made in a given copy, it is irreversible for 220that copy, so the ordinary GNU General Public License applies to all 221subsequent copies and derivative works made from that copy. 222 223 This option is useful when you wish to copy part of the code of 224the Library into a program that is not a library. 225 226 4. You may copy and distribute the Library (or a portion or 227derivative of it, under Section 2) in object code or executable form 228under the terms of Sections 1 and 2 above provided that you accompany 229it with the complete corresponding machine-readable source code, which 230must be distributed under the terms of Sections 1 and 2 above on a 231medium customarily used for software interchange. 232 233 If distribution of object code is made by offering access to copy 234from a designated place, then offering equivalent access to copy the 235source code from the same place satisfies the requirement to 236distribute the source code, even though third parties are not 237compelled to copy the source along with the object code. 238 239 5. A program that contains no derivative of any portion of the 240Library, but is designed to work with the Library by being compiled or 241linked with it, is called a "work that uses the Library". Such a 242work, in isolation, is not a derivative work of the Library, and 243therefore falls outside the scope of this License. 244 245 However, linking a "work that uses the Library" with the Library 246creates an executable that is a derivative of the Library (because it 247contains portions of the Library), rather than a "work that uses the 248library". The executable is therefore covered by this License. 249Section 6 states terms for distribution of such executables. 250 251 When a "work that uses the Library" uses material from a header file 252that is part of the Library, the object code for the work may be a 253derivative work of the Library even though the source code is not. 254Whether this is true is especially significant if the work can be 255linked without the Library, or if the work is itself a library. The 256threshold for this to be true is not precisely defined by law. 257 258 If such an object file uses only numerical parameters, data 259structure layouts and accessors, and small macros and small inline 260functions (ten lines or less in length), then the use of the object 261file is unrestricted, regardless of whether it is legally a derivative 262work. (Executables containing this object code plus portions of the 263Library will still fall under Section 6.) 264 265 Otherwise, if the work is a derivative of the Library, you may 266distribute the object code for the work under the terms of Section 6. 267Any executables containing that work also fall under Section 6, 268whether or not they are linked directly with the Library itself. 269 270 6. As an exception to the Sections above, you may also combine or 271link a "work that uses the Library" with the Library to produce a 272work containing portions of the Library, and distribute that work 273under terms of your choice, provided that the terms permit 274modification of the work for the customer's own use and reverse 275engineering for debugging such modifications. 276 277 You must give prominent notice with each copy of the work that the 278Library is used in it and that the Library and its use are covered by 279this License. You must supply a copy of this License. If the work 280during execution displays copyright notices, you must include the 281copyright notice for the Library among them, as well as a reference 282directing the user to the copy of this License. Also, you must do one 283of these things: 284 285 a) Accompany the work with the complete corresponding 286 machine-readable source code for the Library including whatever 287 changes were used in the work (which must be distributed under 288 Sections 1 and 2 above); and, if the work is an executable linked 289 with the Library, with the complete machine-readable "work that 290 uses the Library", as object code and/or source code, so that the 291 user can modify the Library and then relink to produce a modified 292 executable containing the modified Library. (It is understood 293 that the user who changes the contents of definitions files in the 294 Library will not necessarily be able to recompile the application 295 to use the modified definitions.) 296 297 b) Use a suitable shared library mechanism for linking with the 298 Library. A suitable mechanism is one that (1) uses at run time a 299 copy of the library already present on the user's computer system, 300 rather than copying library functions into the executable, and (2) 301 will operate properly with a modified version of the library, if 302 the user installs one, as long as the modified version is 303 interface-compatible with the version that the work was made with. 304 305 c) Accompany the work with a written offer, valid for at 306 least three years, to give the same user the materials 307 specified in Subsection 6a, above, for a charge no more 308 than the cost of performing this distribution. 309 310 d) If distribution of the work is made by offering access to copy 311 from a designated place, offer equivalent access to copy the above 312 specified materials from the same place. 313 314 e) Verify that the user has already received a copy of these 315 materials or that you have already sent this user a copy. 316 317 For an executable, the required form of the "work that uses the 318Library" must include any data and utility programs needed for 319reproducing the executable from it. However, as a special exception, 320the materials to be distributed need not include anything that is 321normally distributed (in either source or binary form) with the major 322components (compiler, kernel, and so on) of the operating system on 323which the executable runs, unless that component itself accompanies 324the executable. 325 326 It may happen that this requirement contradicts the license 327restrictions of other proprietary libraries that do not normally 328accompany the operating system. Such a contradiction means you cannot 329use both them and the Library together in an executable that you 330distribute. 331 332 7. You may place library facilities that are a work based on the 333Library side-by-side in a single library together with other library 334facilities not covered by this License, and distribute such a combined 335library, provided that the separate distribution of the work based on 336the Library and of the other library facilities is otherwise 337permitted, and provided that you do these two things: 338 339 a) Accompany the combined library with a copy of the same work 340 based on the Library, uncombined with any other library 341 facilities. This must be distributed under the terms of the 342 Sections above. 343 344 b) Give prominent notice with the combined library of the fact 345 that part of it is a work based on the Library, and explaining 346 where to find the accompanying uncombined form of the same work. 347 348 8. You may not copy, modify, sublicense, link with, or distribute 349the Library except as expressly provided under this License. Any 350attempt otherwise to copy, modify, sublicense, link with, or 351distribute the Library is void, and will automatically terminate your 352rights under this License. However, parties who have received copies, 353or rights, from you under this License will not have their licenses 354terminated so long as such parties remain in full compliance. 355 356 9. You are not required to accept this License, since you have not 357signed it. However, nothing else grants you permission to modify or 358distribute the Library or its derivative works. These actions are 359prohibited by law if you do not accept this License. Therefore, by 360modifying or distributing the Library (or any work based on the 361Library), you indicate your acceptance of this License to do so, and 362all its terms and conditions for copying, distributing or modifying 363the Library or works based on it. 364 365 10. Each time you redistribute the Library (or any work based on the 366Library), the recipient automatically receives a license from the 367original licensor to copy, distribute, link with or modify the Library 368subject to these terms and conditions. You may not impose any further 369restrictions on the recipients' exercise of the rights granted herein. 370You are not responsible for enforcing compliance by third parties with 371this License. 372 373 11. If, as a consequence of a court judgment or allegation of patent 374infringement or for any other reason (not limited to patent issues), 375conditions are imposed on you (whether by court order, agreement or 376otherwise) that contradict the conditions of this License, they do not 377excuse you from the conditions of this License. If you cannot 378distribute so as to satisfy simultaneously your obligations under this 379License and any other pertinent obligations, then as a consequence you 380may not distribute the Library at all. For example, if a patent 381license would not permit royalty-free redistribution of the Library by 382all those who receive copies directly or indirectly through you, then 383the only way you could satisfy both it and this License would be to 384refrain entirely from distribution of the Library. 385 386If any portion of this section is held invalid or unenforceable under any 387particular circumstance, the balance of the section is intended to apply, 388and the section as a whole is intended to apply in other circumstances. 389 390It is not the purpose of this section to induce you to infringe any 391patents or other property right claims or to contest validity of any 392such claims; this section has the sole purpose of protecting the 393integrity of the free software distribution system which is 394implemented by public license practices. Many people have made 395generous contributions to the wide range of software distributed 396through that system in reliance on consistent application of that 397system; it is up to the author/donor to decide if he or she is willing 398to distribute software through any other system and a licensee cannot 399impose that choice. 400 401This section is intended to make thoroughly clear what is believed to 402be a consequence of the rest of this License. 403 404 12. If the distribution and/or use of the Library is restricted in 405certain countries either by patents or by copyrighted interfaces, the 406original copyright holder who places the Library under this License may add 407an explicit geographical distribution limitation excluding those countries, 408so that distribution is permitted only in or among countries not thus 409excluded. In such case, this License incorporates the limitation as if 410written in the body of this License. 411 412 13. The Free Software Foundation may publish revised and/or new 413versions of the Lesser General Public License from time to time. 414Such new versions will be similar in spirit to the present version, 415but may differ in detail to address new problems or concerns. 416 417Each version is given a distinguishing version number. If the Library 418specifies a version number of this License which applies to it and 419"any later version", you have the option of following the terms and 420conditions either of that version or of any later version published by 421the Free Software Foundation. If the Library does not specify a 422license version number, you may choose any version ever published by 423the Free Software Foundation. 424 425 14. If you wish to incorporate parts of the Library into other free 426programs whose distribution conditions are incompatible with these, 427write to the author to ask for permission. For software which is 428copyrighted by the Free Software Foundation, write to the Free 429Software Foundation; we sometimes make exceptions for this. Our 430decision will be guided by the two goals of preserving the free status 431of all derivatives of our free software and of promoting the sharing 432and reuse of software generally. 433 434 NO WARRANTY 435 436 15. BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NO 437WARRANTY FOR THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE LAW. 438EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR 439OTHER PARTIES PROVIDE THE LIBRARY "AS IS" WITHOUT WARRANTY OF ANY 440KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE 441IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 442PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE 443LIBRARY IS WITH YOU. SHOULD THE LIBRARY PROVE DEFECTIVE, YOU ASSUME 444THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 445 446 16. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN 447WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY 448AND/OR REDISTRIBUTE THE LIBRARY AS PERMITTED ABOVE, BE LIABLE TO YOU 449FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR 450CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE 451LIBRARY (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING 452RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A 453FAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF 454SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH 455DAMAGES. 456 457 END OF TERMS AND CONDITIONS 458