3 <title>GNU General Public License</title>
4 <pubdate>Version 2, June 1991</pubdate>
6 <year>1989, 1991</year>
7 <holder>Free Software Foundation, Inc.</holder>
9 <legalnotice id="gpl-legalnotice">
11 <address>Free Software Foundation, Inc.
12 <street>51 Franklin Street, Fifth Floor</street>,
13 <city>Boston</city>, <state>MA</state> <postcode>02110-1301</postcode>
14 <country>USA</country>
17 <para>Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.</para>
19 <releaseinfo>Version 2, June 1991</releaseinfo>
21 <title>GNU General Public License</title>
23 <title>Preamble</title>
24 <para>The licenses for most software are designed to take away your
25 freedom to share and change it. By contrast, the GNU General Public License is
26 intended to guarantee your freedom to share and change
27 free software - to make sure the software is free for all its users.
28 This General Public License applies to most of the Free Software
29 Foundation's software and to any other program whose authors commit
30 to using it. (Some other Free Software Foundation software is covered
31 by the GNU Library General Public License instead.) You can apply it
32 to your programs, too.</para>
34 <para>When we speak of free software, we are referring to freedom, not price.
35 Our General Public Licenses are designed to make sure that you have the
36 freedom to distribute copies of free software (and charge for this
37 service if you wish), that you receive source code or can get it if you
38 want it, that you can change the software or use pieces of it in new free
39 programs; and that you know you can do these things.</para>
41 <para>To protect your rights, we need to make restrictions that forbid anyone
42 to deny you these rights or to ask you to surrender the rights. These
43 restrictions translate to certain responsibilities for you if you distribute
44 copies of the software, or if you modify it.</para>
46 <para>For example, if you distribute copies of such a program, whether gratis or
47 for a fee, you must give the recipients all the rights that you have. You
48 must make sure that they, too, receive or can get the source code. And you
49 must show them these terms so they know their rights.</para>
51 <para>We protect your rights with two steps:
54 <para>copyright the software, and</para>
57 <para>offer you this license which gives you legal permission to copy,
58 distribute and/or modify the software.</para>
63 <para>Also, for each author's protection and ours, we want to make certain that
64 everyone understands that there is no warranty for this free software. If
65 the software is modified by someone else and passed on, we want its
66 recipients to know that what they have is not the original, so that any
67 problems introduced by others will not reflect on the original authors'
70 <para>Finally, any free program is threatened constantly by software patents.
71 We wish to avoid the danger that redistributors of a free program will
72 individually obtain patent licenses, in effect making the program
73 proprietary. To prevent this, we have made it clear that any patent must be
74 licensed for everyone's free use or not licensed at all.</para>
76 <para>The precise terms and conditions for copying, distribution and modification
80 <title>TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION</title>
81 <section id="gpl-2-0">
82 <title>Section 0</title>
83 <para>This License applies to any program or other work which contains a notice
84 placed by the copyright holder saying it may be distributed under the terms
85 of this General Public License. The <quote>Program</quote>, below, refers to any such
86 program or work, and a
87 <quote>work based on the Program</quote> means either
88 the Program or any derivative work under copyright law: that is to say, a
89 work containing the Program or a portion of it, either verbatim or with
90 modifications and/or translated into another language. (Hereinafter, translation
91 is included without limitation in the term
92 <quote>modification</quote>.) Each licensee is addressed as <quote>you</quote>.</para>
94 <para>Activities other than copying, distribution and modification are not covered by
95 this License; they are outside its scope. The act of running the Program is not
96 restricted, and the output from the Program is covered only if its contents
97 constitute a work based on the Program (independent of having been made by running
98 the Program). Whether that is true depends on what the Program does.</para>
100 <section id="gpl-2-1">
101 <title>Section 1</title>
102 <para>You may copy and distribute verbatim copies of the Program's source code as you
103 receive it, in any medium, provided that you conspicuously and appropriately
104 publish on each copy an appropriate copyright notice and disclaimer of warranty;
105 keep intact all the notices that refer to this License and to the absence of any
106 warranty; and give any other recipients of the Program a copy of this License
107 along with the Program.</para>
109 <para>You may charge a fee for the physical act of transferring a copy, and you may at
110 your option offer warranty protection in exchange for a fee.</para>
112 <section id="gpl-2-2">
113 <title>Section 2</title>
114 <para>You may modify your copy or copies of the Program or any portion of it, thus
115 forming a work based on the Program, and copy and distribute such modifications
116 or work under the terms of
117 <link linkend="gpl-2-1">Section 1</link> above, provided
118 that you also meet all of these conditions:
119 <orderedlist numeration="loweralpha">
121 <para>You must cause the modified files to carry prominent notices stating that
122 you changed the files and the date of any change.</para>
125 <para>You must cause any work that you distribute or publish, that in whole or
126 in part contains or is derived from the Program or any part thereof, to be
127 licensed as a whole at no charge to all third parties under the terms of
131 <para>If the modified program normally reads commands interactively when run, you
132 must cause it, when started running for such interactive use in the most
133 ordinary way, to print or display an announcement including an appropriate
134 copyright notice and a notice that there is no warranty (or else, saying
135 that you provide a warranty) and that users may redistribute the program
136 under these conditions, and telling the user how to view a copy of this
137 License. (Exception: If the Program itself is interactive but does not
138 normally print such an announcement, your work based on the Program is not
139 required to print an announcement.)</para>
144 <para>These requirements apply to the modified work as a whole. If identifiable sections
145 of that work are not derived from the Program, and can be reasonably considered
146 independent and separate works in themselves, then this License, and its terms,
147 do not apply to those sections when you distribute them as separate works. But when
148 you distribute the same sections as part of a whole which is a work based on the
149 Program, the distribution of the whole must be on the terms of this License, whose
150 permissions for other licensees extend to the entire whole, and thus to each and
151 every part regardless of who wrote it.</para>
153 <para>Thus, it is not the intent of this section to claim rights or contest your rights
154 to work written entirely by you; rather, the intent is to exercise the right to control
155 the distribution of derivative or collective works based on the Program.</para>
157 <para>In addition, mere aggregation of another work not based on the Program with the Program
158 (or with a work based on the Program) on a volume of a storage or distribution medium
159 does not bring the other work under the scope of this License.</para>
161 <section id="gpl-2-3">
162 <title>Section 3</title>
163 <para>You may copy and distribute the Program (or a work based on it, under
164 <link linkend="gpl-2-2">Section 2</link> in object code or executable form under the terms of
165 <link linkend="gpl-2-1">Sections 1</link> and
166 <link linkend="gpl-2-2">2</link> above provided that you also do one of the following:
167 <orderedlist numeration="loweralpha">
169 <para>Accompany it with the complete corresponding machine-readable source code, which
170 must be distributed under the terms of Sections 1 and 2 above on a medium
171 customarily used for software interchange; or,</para>
174 <para>Accompany it with a written offer, valid for at least three years, to give any
175 third party, for a charge no more than your cost of physically performing source
176 distribution, a complete machine-readable copy of the corresponding source code,
177 to be distributed under the terms of Sections 1 and 2 above on a medium customarily
178 used for software interchange; or,</para>
181 <para>Accompany it with the information you received as to the offer to distribute
182 corresponding source code. (This alternative is allowed only for noncommercial
183 distribution and only if you received the program in object code or executable form
184 with such an offer, in accord with Subsection b above.)</para>
189 <para>The source code for a work means the preferred form of the work for making modifications
190 to it. For an executable work, complete source code means all the source code for all modules
191 it contains, plus any associated interface definition files, plus the scripts used to control
192 compilation and installation of the executable. However, as a special exception, the source
193 code distributed need not include anything that is normally distributed (in either source or
194 binary form) with the major components (compiler, kernel, and so on) of the operating system
195 on which the executable runs, unless that component itself accompanies the executable.</para>
197 <para>If distribution of executable or object code is made by offering access to copy from a
198 designated place, then offering equivalent access to copy the source code from the same place
199 counts as distribution of the source code, even though third parties are not compelled to
200 copy the source along with the object code.</para>
202 <section id="gpl-2-4">
203 <title>Section 4</title>
204 <para>You may not copy, modify, sublicense, or distribute the Program except as expressly provided
205 under this License. Any attempt otherwise to copy, modify, sublicense or distribute the
206 Program is void, and will automatically terminate your rights under this License. However,
207 parties who have received copies, or rights, from you under this License will not have their
208 licenses terminated so long as such parties remain in full compliance.</para>
210 <section id="gpl-2-5">
211 <title>Section 5</title>
212 <para>You are not required to accept this License, since you have not signed it. However, nothing
213 else grants you permission to modify or distribute the Program or its derivative works.
214 These actions are prohibited by law if you do not accept this License. Therefore, by modifying
215 or distributing the Program (or any work based on the Program), you indicate your acceptance
216 of this License to do so, and all its terms and conditions for copying, distributing or
217 modifying the Program or works based on it.</para>
219 <section id="gpl-2-6">
220 <title>Section 6</title>
221 <para>Each time you redistribute the Program (or any work based on the Program), the recipient
222 automatically receives a license from the original licensor to copy, distribute or modify
223 the Program subject to these terms and conditions. You may not impose any further restrictions
224 on the recipients' exercise of the rights granted herein. You are not responsible for enforcing
225 compliance by third parties to this License.</para>
227 <section id="gpl-2-7">
228 <title>Section 7</title>
229 <para>If, as a consequence of a court judgment or allegation of patent infringement or for any other
230 reason (not limited to patent issues), conditions are imposed on you (whether by court order,
231 agreement or otherwise) that contradict the conditions of this License, they do not excuse you
232 from the conditions of this License. If you cannot distribute so as to satisfy simultaneously
233 your obligations under this License and any other pertinent obligations, then as a consequence
234 you may not distribute the Program at all. For example, if a patent license would not permit
235 royalty-free redistribution of the Program by all those who receive copies directly or
236 indirectly through you, then the only way you could satisfy both it and this License would be
237 to refrain entirely from distribution of the Program.</para>
239 <para>If any portion of this section is held invalid or unenforceable under any particular circumstance,
240 the balance of the section is intended to apply and the section as a whole is intended to apply
241 in other circumstances.</para>
243 <para>It is not the purpose of this section to induce you to infringe any patents or other property
244 right claims or to contest validity of any such claims; this section has the sole purpose of
245 protecting the integrity of the free software distribution system, which is implemented by public
246 license practices. Many people have made generous contributions to the wide range of software
247 distributed through that system in reliance on consistent application of that system; it is up
248 to the author/donor to decide if he or she is willing to distribute software through any other
249 system and a licensee cannot impose that choice.</para>
251 <para>This section is intended to make thoroughly clear what is believed to be a consequence of the
252 rest of this License.</para>
254 <section id="gpl-2-8">
255 <title>Section 8</title>
256 <para>If the distribution and/or use of the Program is restricted in certain countries either by patents
257 or by copyrighted interfaces, the original copyright holder who places the Program under this License
258 may add an explicit geographical distribution limitation excluding those countries, so that
259 distribution is permitted only in or among countries not thus excluded. In such case, this License
260 incorporates the limitation as if written in the body of this License.</para>
262 <section id="gpl-2-9">
263 <title>Section 9</title>
264 <para>The Free Software Foundation may publish revised and/or new versions of the General Public License
265 from time to time. Such new versions will be similar in spirit to the present version, but may differ
266 in detail to address new problems or concerns.</para>
268 <para>Each version is given a distinguishing version number. If the Program specifies a version number of
269 this License which applies to it and <quote>any later version</quote>, you have the option of following the terms
270 and conditions either of that version or of any later version published by the Free Software
271 Foundation. If the Program does not specify a version number of this License, you may choose any
272 version ever published by the Free Software Foundation.</para>
274 <section id="gpl-2-10">
275 <title>Section 10</title>
276 <para>If you wish to incorporate parts of the Program into other free programs whose distribution
277 conditions are different, write to the author to ask for permission. For software which is copyrighted
278 by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions
279 for this. Our decision will be guided by the two goals of preserving the free status of all
280 derivatives of our free software and of promoting the sharing and reuse of software generally.</para>
282 <section id="gpl-2-11">
283 <title>NO WARRANTY Section 11</title>
284 <para>BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT
285 PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR
286 OTHER PARTIES PROVIDE THE PROGRAM <quote>AS IS</quote> WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED,
287 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
288 PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
289 PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.</para>
291 <section id="gpl-2-12">
292 <title>Section 12</title>
293 <para>IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR
294 ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU
295 FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
296 USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED
297 INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH
298 ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
301 <para>END OF TERMS AND CONDITIONS</para>
305 <title>How to Apply These Terms to Your New Programs</title>
306 <para>If you develop a new program, and you want it to be of the greatest
307 possible use to the public, the best way to achieve this is to make it
308 free software which everyone can redistribute and change under these terms.</para>
310 <para>To do so, attach the following notices to the program. It is safest
311 to attach them to the start of each source file to most effectively
312 convey the exclusion of warranty; and each file should have at least
313 the <quote>copyright</quote> line and a pointer to where the full notice is found.</para>
315 <para><one line to give the program's name and a brief idea of what it does.>
316 Copyright (C) <year> <name of author></para>
318 <para>This program is free software; you can redistribute it and/or modify
319 it under the terms of the GNU General Public License as published by
320 the Free Software Foundation; either version 2 of the License, or
321 (at your option) any later version.</para>
323 <para>This program is distributed in the hope that it will be useful,
324 but WITHOUT ANY WARRANTY; without even the implied warranty of
325 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
326 GNU General Public License for more details.</para>
328 <para>You should have received a copy of the GNU General Public License
329 along with this program; if not, write to the Free Software
330 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA</para>
332 <para>Also add information on how to contact you by electronic and paper mail.</para>
334 <para>If the program is interactive, make it output a short notice like this
335 when it starts in an interactive mode:</para>
337 <para>Gnomovision version 69, Copyright (C) year name of author
338 Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type <quote>show w</quote>.
339 This is free software, and you are welcome to redistribute it
340 under certain conditions; type <quote>show c</quote> for details.</para>
342 <para>The hypothetical commands <quote>show w</quote> and <quote>show c</quote> should
343 show the appropriate parts of the General Public License. Of course, the commands you
344 use may be called something other than <quote>show w</quote> and <quote>show c</quote>;
345 they could even be mouse-clicks or menu items--whatever suits your program.</para>
347 <para>You should also get your employer (if you work as a programmer) or your
348 school, if any, to sign a <quote>copyright disclaimer</quote> for the program, if
349 necessary. Here is a sample; alter the names:</para>
351 <para>Yoyodyne, Inc., hereby disclaims all copyright interest in the program
352 <quote>Gnomovision</quote> (which makes passes at compilers) written by James Hacker.</para>
354 <para><signature of Ty Coon>, 1 April 1989
355 Ty Coon, President of Vice</para>
357 <para>This General Public License does not permit incorporating your program into
358 proprietary programs. If your program is a subroutine library, you may
359 consider it more useful to permit linking proprietary applications with the
360 library. If this is what you want to do, use the GNU Library General
361 Public License instead of this License.</para>