0031642: Visualization - crash in Graphic3d_Structure::SetVisual() on redisplaying...
[occt.git] / dox / license.md
CommitLineData
745c1386 1License {#occt_public_license}
2=======
3
4Open CASCADE Technology is available under GNU Lesser General Public License
5(LGPL) version 2.1 with additional exception.
6
7@section license_lgpl_21 GNU LESSER GENERAL PUBLIC LICENSE
8
9 Version 2.1, February 1999
10
11 Copyright (C) 1991, 1999 Free Software Foundation, Inc.
12 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
13 Everyone is permitted to copy and distribute verbatim copies
14 of this license document, but changing it is not allowed.
15
16 [This is the first released version of the Lesser GPL. It also counts
17 as the successor of the GNU Library Public License, version 2, hence
18 the version number 2.1.]
19
20### Preamble
21
22 The licenses for most software are designed to take away your
23freedom to share and change it. By contrast, the GNU General Public
24Licenses are intended to guarantee your freedom to share and change
25free software--to make sure the software is free for all its users.
26
27 This license, the Lesser General Public License, applies to some
28specially designated software packages--typically libraries--of the
29Free Software Foundation and other authors who decide to use it. You
30can use it too, but we suggest you first think carefully about whether
31this license or the ordinary General Public License is the better
32strategy to use in any particular case, based on the explanations below.
33
34 When we speak of free software, we are referring to freedom of use,
35not price. Our General Public Licenses are designed to make sure that
36you have the freedom to distribute copies of free software (and charge
37for this service if you wish); that you receive source code or can get
38it if you want it; that you can change the software and use pieces of
39it in new free programs; and that you are informed that you can do
40these things.
41
42 To protect your rights, we need to make restrictions that forbid
43distributors to deny you these rights or to ask you to surrender these
44rights. These restrictions translate to certain responsibilities for
45you if you distribute copies of the library or if you modify it.
46
47 For example, if you distribute copies of the library, whether gratis
48or for a fee, you must give the recipients all the rights that we gave
49you. You must make sure that they, too, receive or can get the source
50code. If you link other code with the library, you must provide
51complete object files to the recipients, so that they can relink them
52with the library after making changes to the library and recompiling
53it. And you must show them these terms so they know their rights.
54
55 We protect your rights with a two-step method: (1) we copyright the
56library, and (2) we offer you this license, which gives you legal
57permission to copy, distribute and/or modify the library.
58
59 To protect each distributor, we want to make it very clear that
60there is no warranty for the free library. Also, if the library is
61modified by someone else and passed on, the recipients should know
62that what they have is not the original version, so that the original
63author's reputation will not be affected by problems that might be
64introduced by others.
65
66 Finally, software patents pose a constant threat to the existence of
67any free program. We wish to make sure that a company cannot
68effectively restrict the users of a free program by obtaining a
69restrictive license from a patent holder. Therefore, we insist that
70any patent license obtained for a version of the library must be
71consistent with the full freedom of use specified in this license.
72
73 Most GNU software, including some libraries, is covered by the
74ordinary GNU General Public License. This license, the GNU Lesser
75General Public License, applies to certain designated libraries, and
76is quite different from the ordinary General Public License. We use
77this license for certain libraries in order to permit linking those
78libraries into non-free programs.
79
80 When a program is linked with a library, whether statically or using
81a shared library, the combination of the two is legally speaking a
82combined work, a derivative of the original library. The ordinary
83General Public License therefore permits such linking only if the
84entire combination fits its criteria of freedom. The Lesser General
85Public License permits more lax criteria for linking other code with
86the library.
87
88 We call this license the "Lesser" General Public License because it
89does Less to protect the user's freedom than the ordinary General
90Public License. It also provides other free software developers Less
91of an advantage over competing non-free programs. These disadvantages
92are the reason we use the ordinary General Public License for many
93libraries. However, the Lesser license provides advantages in certain
94special circumstances.
95
96 For example, on rare occasions, there may be a special need to
97encourage the widest possible use of a certain library, so that it becomes
98a de-facto standard. To achieve this, non-free programs must be
99allowed to use the library. A more frequent case is that a free
100library does the same job as widely used non-free libraries. In this
101case, there is little to gain by limiting the free library to free
102software only, so we use the Lesser General Public License.
103
104 In other cases, permission to use a particular library in non-free
105programs enables a greater number of people to use a large body of
106free software. For example, permission to use the GNU C Library in
107non-free programs enables many more people to use the whole GNU
108operating system, as well as its variant, the GNU/Linux operating
109system.
110
111 Although the Lesser General Public License is Less protective of the
112users' freedom, it does ensure that the user of a program that is
113linked with the Library has the freedom and the wherewithal to run
114that program using a modified version of the Library.
115
116 The precise terms and conditions for copying, distribution and
117modification follow. Pay close attention to the difference between a
118"work based on the library" and a "work that uses the library". The
119former contains code derived from the library, whereas the latter must
120be combined with the library in order to run.
121
122### TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
123
124- 0. This License Agreement applies to any software library or other
125 program which contains a notice placed by the copyright holder or
126 other authorized party saying it may be distributed under the terms of
127 this Lesser General Public License (also called "this License").
128 Each licensee is addressed as "you".
129
130 A "library" means a collection of software functions and/or data
131 prepared so as to be conveniently linked with application programs
132 (which use some of those functions and data) to form executables.
133
134 The "Library", below, refers to any such software library or work
135 which has been distributed under these terms. A "work based on the
136 Library" means either the Library or any derivative work under
137 copyright law: that is to say, a work containing the Library or a
138 portion of it, either verbatim or with modifications and/or translated
139 straightforwardly into another language. (Hereinafter, translation is
140 included without limitation in the term "modification".)
141
142 "Source code" for a work means the preferred form of the work for
143 making modifications to it. For a library, complete source code means
144 all the source code for all modules it contains, plus any associated
145 interface definition files, plus the scripts used to control compilation
146 and installation of the library.
147
148 Activities other than copying, distribution and modification are not
149 covered by this License; they are outside its scope. The act of
150 running a program using the Library is not restricted, and output from
151 such a program is covered only if its contents constitute a work based
152 on the Library (independent of the use of the Library in a tool for
153 writing it). Whether that is true depends on what the Library does
154 and what the program that uses the Library does.
155
1561. You may copy and distribute verbatim copies of the Library's
157 complete source code as you receive it, in any medium, provided that
158 you conspicuously and appropriately publish on each copy an
159 appropriate copyright notice and disclaimer of warranty; keep intact
160 all the notices that refer to this License and to the absence of any
161 warranty; and distribute a copy of this License along with the
162 Library.
163
164 You may charge a fee for the physical act of transferring a copy,
165 and you may at your option offer warranty protection in exchange for a
166 fee.
167
1682. You may modify your copy or copies of the Library or any portion
169 of it, thus forming a work based on the Library, and copy and
170 distribute such modifications or work under the terms of Section 1
171 above, provided that you also meet all of these conditions:
172
173 1. The modified work must itself be a software library.
174
175 2. You must cause the files modified to carry prominent notices
176 stating that you changed the files and the date of any change.
177
178 3. You must cause the whole of the work to be licensed at no
179 charge to all third parties under the terms of this License.
180
181 4. If a facility in the modified Library refers to a function or a
182 table of data to be supplied by an application program that uses
183 the facility, other than as an argument passed when the facility
184 is invoked, then you must make a good faith effort to ensure that,
185 in the event an application does not supply such function or
186 table, the facility still operates, and performs whatever part of
187 its purpose remains meaningful.
188
189 (For example, a function in a library to compute square roots has
190 a purpose that is entirely well-defined independent of the
191 application. Therefore, Subsection 2d requires that any
192 application-supplied function or table used by this function must
193 be optional: if the application does not supply it, the square
194 root function must still compute square roots.)
195
196 These requirements apply to the modified work as a whole. If
197 identifiable sections of that work are not derived from the Library,
198 and can be reasonably considered independent and separate works in
199 themselves, then this License, and its terms, do not apply to those
200 sections when you distribute them as separate works. But when you
201 distribute the same sections as part of a whole which is a work based
202 on the Library, the distribution of the whole must be on the terms of
203 this License, whose permissions for other licensees extend to the
204 entire whole, and thus to each and every part regardless of who wrote
205 it.
206
207 Thus, it is not the intent of this section to claim rights or contest
208 your rights to work written entirely by you; rather, the intent is to
209 exercise the right to control the distribution of derivative or
210 collective works based on the Library.
211
212 In addition, mere aggregation of another work not based on the Library
213 with the Library (or with a work based on the Library) on a volume of
214 a storage or distribution medium does not bring the other work under
215 the scope of this License.
216
2173. You may opt to apply the terms of the ordinary GNU General Public
218 License instead of this License to a given copy of the Library. To do
219 this, you must alter all the notices that refer to this License, so
220 that they refer to the ordinary GNU General Public License, version 2,
221 instead of to this License. (If a newer version than version 2 of the
222 ordinary GNU General Public License has appeared, then you can specify
223 that version instead if you wish.) Do not make any other change in
224 these notices.
225
226 Once this change is made in a given copy, it is irreversible for
227 that copy, so the ordinary GNU General Public License applies to all
228 subsequent copies and derivative works made from that copy.
229
230 This option is useful when you wish to copy part of the code of
231 the Library into a program that is not a library.
232
2334. You may copy and distribute the Library (or a portion or
234 derivative of it, under Section 2) in object code or executable form
235 under the terms of Sections 1 and 2 above provided that you accompany
236 it with the complete corresponding machine-readable source code, which
237 must be distributed under the terms of Sections 1 and 2 above on a
238 medium customarily used for software interchange.
239
240 If distribution of object code is made by offering access to copy
241 from a designated place, then offering equivalent access to copy the
242 source code from the same place satisfies the requirement to
243 distribute the source code, even though third parties are not
244 compelled to copy the source along with the object code.
245
2465. A program that contains no derivative of any portion of the
247 Library, but is designed to work with the Library by being compiled or
248 linked with it, is called a "work that uses the Library". Such a
249 work, in isolation, is not a derivative work of the Library, and
250 therefore falls outside the scope of this License.
251
252 However, linking a "work that uses the Library" with the Library
253 creates an executable that is a derivative of the Library (because it
254 contains portions of the Library), rather than a "work that uses the
255 library". The executable is therefore covered by this License.
256 Section 6 states terms for distribution of such executables.
257
258 When a "work that uses the Library" uses material from a header file
259 that is part of the Library, the object code for the work may be a
260 derivative work of the Library even though the source code is not.
261 Whether this is true is especially significant if the work can be
262 linked without the Library, or if the work is itself a library. The
263 threshold for this to be true is not precisely defined by law.
264
265 If such an object file uses only numerical parameters, data
266 structure layouts and accessors, and small macros and small inline
267 functions (ten lines or less in length), then the use of the object
268 file is unrestricted, regardless of whether it is legally a derivative
269 work. (Executables containing this object code plus portions of the
270 Library will still fall under Section 6.)
271
272 Otherwise, if the work is a derivative of the Library, you may
273 distribute the object code for the work under the terms of Section 6.
274 Any executables containing that work also fall under Section 6,
275 whether or not they are linked directly with the Library itself.
276
2776. As an exception to the Sections above, you may also combine or
278 link a "work that uses the Library" with the Library to produce a
279 work containing portions of the Library, and distribute that work
280 under terms of your choice, provided that the terms permit
281 modification of the work for the customer's own use and reverse
282 engineering for debugging such modifications.
283
284 You must give prominent notice with each copy of the work that the
285 Library is used in it and that the Library and its use are covered by
286 this License. You must supply a copy of this License. If the work
287 during execution displays copyright notices, you must include the
288 copyright notice for the Library among them, as well as a reference
289 directing the user to the copy of this License. Also, you must do one
290 of these things:
291
292 1. Accompany the work with the complete corresponding
293 machine-readable source code for the Library including whatever
294 changes were used in the work (which must be distributed under
295 Sections 1 and 2 above); and, if the work is an executable linked
296 with the Library, with the complete machine-readable "work that
297 uses the Library", as object code and/or source code, so that the
298 user can modify the Library and then relink to produce a modified
299 executable containing the modified Library. (It is understood
300 that the user who changes the contents of definitions files in the
301 Library will not necessarily be able to recompile the application
302 to use the modified definitions.)
303
304 2. Use a suitable shared library mechanism for linking with the
305 Library. A suitable mechanism is one that (1) uses at run time a
306 copy of the library already present on the user's computer system,
307 rather than copying library functions into the executable, and (2)
308 will operate properly with a modified version of the library, if
309 the user installs one, as long as the modified version is
310 interface-compatible with the version that the work was made with.
311
312 3. Accompany the work with a written offer, valid for at
313 least three years, to give the same user the materials
314 specified in Subsection 6a, above, for a charge no more
315 than the cost of performing this distribution.
316
317 4. If distribution of the work is made by offering access to copy
318 from a designated place, offer equivalent access to copy the above
319 specified materials from the same place.
320
321 5. Verify that the user has already received a copy of these
322 materials or that you have already sent this user a copy.
323
324 For an executable, the required form of the "work that uses the
325 Library" must include any data and utility programs needed for
326 reproducing the executable from it. However, as a special exception,
327 the materials to be distributed need not include anything that is
328 normally distributed (in either source or binary form) with the major
329 components (compiler, kernel, and so on) of the operating system on
330 which the executable runs, unless that component itself accompanies
331 the executable.
332
333 It may happen that this requirement contradicts the license
334 restrictions of other proprietary libraries that do not normally
335 accompany the operating system. Such a contradiction means you cannot
336 use both them and the Library together in an executable that you
337 distribute.
338
3397. You may place library facilities that are a work based on the
340 Library side-by-side in a single library together with other library
341 facilities not covered by this License, and distribute such a combined
342 library, provided that the separate distribution of the work based on
343 the Library and of the other library facilities is otherwise
344 permitted, and provided that you do these two things:
345
346 1. Accompany the combined library with a copy of the same work
347 based on the Library, uncombined with any other library
348 facilities. This must be distributed under the terms of the
349 Sections above.
350
351 2. Give prominent notice with the combined library of the fact
352 that part of it is a work based on the Library, and explaining
353 where to find the accompanying uncombined form of the same work.
354
3558. You may not copy, modify, sublicense, link with, or distribute
356 the Library except as expressly provided under this License. Any
357 attempt otherwise to copy, modify, sublicense, link with, or
358 distribute the Library is void, and will automatically terminate your
359 rights under this License. However, parties who have received copies,
360 or rights, from you under this License will not have their licenses
361 terminated so long as such parties remain in full compliance.
362
3639. You are not required to accept this License, since you have not
364 signed it. However, nothing else grants you permission to modify or
365 distribute the Library or its derivative works. These actions are
366 prohibited by law if you do not accept this License. Therefore, by
367 modifying or distributing the Library (or any work based on the
368 Library), you indicate your acceptance of this License to do so, and
369 all its terms and conditions for copying, distributing or modifying
370 the Library or works based on it.
371
37210. Each time you redistribute the Library (or any work based on the
373 Library), the recipient automatically receives a license from the
374 original licensor to copy, distribute, link with or modify the Library
375 subject to these terms and conditions. You may not impose any further
376 restrictions on the recipients' exercise of the rights granted herein.
377 You are not responsible for enforcing compliance by third parties with
378 this License.
379
38011. If, as a consequence of a court judgment or allegation of patent
381 infringement or for any other reason (not limited to patent issues),
382 conditions are imposed on you (whether by court order, agreement or
383 otherwise) that contradict the conditions of this License, they do not
384 excuse you from the conditions of this License. If you cannot
385 distribute so as to satisfy simultaneously your obligations under this
386 License and any other pertinent obligations, then as a consequence you
387 may not distribute the Library at all. For example, if a patent
388 license would not permit royalty-free redistribution of the Library by
389 all those who receive copies directly or indirectly through you, then
390 the only way you could satisfy both it and this License would be to
391 refrain entirely from distribution of the Library.
392
393 If any portion of this section is held invalid or unenforceable under any
394 particular circumstance, the balance of the section is intended to apply,
395 and the section as a whole is intended to apply in other circumstances.
396
397 It is not the purpose of this section to induce you to infringe any
398 patents or other property right claims or to contest validity of any
399 such claims; this section has the sole purpose of protecting the
400 integrity of the free software distribution system which is
401 implemented by public license practices. Many people have made
402 generous contributions to the wide range of software distributed
403 through that system in reliance on consistent application of that
404 system; it is up to the author/donor to decide if he or she is willing
405 to distribute software through any other system and a licensee cannot
406 impose that choice.
407
408 This section is intended to make thoroughly clear what is believed to
409 be a consequence of the rest of this License.
410
41112. If the distribution and/or use of the Library is restricted in
412 certain countries either by patents or by copyrighted interfaces, the
413 original copyright holder who places the Library under this License may add
414 an explicit geographical distribution limitation excluding those countries,
415 so that distribution is permitted only in or among countries not thus
416 excluded. In such case, this License incorporates the limitation as if
417 written in the body of this License.
418
41913. The Free Software Foundation may publish revised and/or new
420 versions of the Lesser General Public License from time to time.
421 Such new versions will be similar in spirit to the present version,
422 but may differ in detail to address new problems or concerns.
423
424 Each version is given a distinguishing version number. If the Library
425 specifies a version number of this License which applies to it and
426 "any later version", you have the option of following the terms and
427 conditions either of that version or of any later version published by
428 the Free Software Foundation. If the Library does not specify a
429 license version number, you may choose any version ever published by
430 the Free Software Foundation.
431
43214. If you wish to incorporate parts of the Library into other free
433 programs whose distribution conditions are incompatible with these,
434 write to the author to ask for permission. For software which is
435 copyrighted by the Free Software Foundation, write to the Free
436 Software Foundation; we sometimes make exceptions for this. Our
437 decision will be guided by the two goals of preserving the free status
438 of all derivatives of our free software and of promoting the sharing
439 and reuse of software generally.
440
441 **NO** **WARRANTY**
442
44315. BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NO
444 WARRANTY FOR THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE LAW.
445 EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR
446 OTHER PARTIES PROVIDE THE LIBRARY "AS IS" WITHOUT WARRANTY OF ANY
447 KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE
448 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
449 PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE
450 LIBRARY IS WITH YOU. SHOULD THE LIBRARY PROVE DEFECTIVE, YOU ASSUME
451 THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
452
45316. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
454 WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY
455 AND/OR REDISTRIBUTE THE LIBRARY AS PERMITTED ABOVE, BE LIABLE TO YOU
456 FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR
457 CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
458 LIBRARY (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
459 RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
460 FAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
461 SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
462 DAMAGES.
463
464### END OF TERMS AND CONDITIONS
465
466### How to Apply These Terms to Your New Libraries
467
468 If you develop a new library, and you want it to be of the greatest
469possible use to the public, we recommend making it free software that
470everyone can redistribute and change. You can do so by permitting
471redistribution under these terms (or, alternatively, under the terms of the
472ordinary General Public License).
473
474 To apply these terms, attach the following notices to the library. It is
475safest to attach them to the start of each source file to most effectively
476convey the exclusion of warranty; and each file should have at least the
477"copyright" line and a pointer to where the full notice is found.
478
479 <one line to give the library's name and a brief idea of what it does.>
480 Copyright (C) <year> <name of author>
481
482 This library is free software; you can redistribute it and/or
483 modify it under the terms of the GNU Lesser General Public
484 License as published by the Free Software Foundation; either
485 version 2.1 of the License, or (at your option) any later version.
486
487 This library is distributed in the hope that it will be useful,
488 but WITHOUT ANY WARRANTY; without even the implied warranty of
489 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
490 Lesser General Public License for more details.
491
492 You should have received a copy of the GNU Lesser General Public
493 License along with this library; if not, write to the Free Software
494 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
495
496Also add information on how to contact you by electronic and paper mail.
497
498You should also get your employer (if you work as a programmer) or your
499school, if any, to sign a "copyright disclaimer" for the library, if
500necessary. Here is a sample; alter the names:
501
502 Yoyodyne, Inc., hereby disclaims all copyright interest in the
503 library `Frob' (a library for tweaking knobs) written by James Random Hacker.
504
505 <signature of Ty Coon>, 1 April 1990
506 Ty Coon, President of Vice
507
508That's all there is to it!
509
510@section occt_lgpl_exception OPEN CASCADE EXCEPTION
511
512### Open CASCADE Exception (version 1.0) to GNU LGPL version 2.1.
513
514The object code (i.e. not a source) form of a "work that uses the Library"
515can incorporate material from a header file that is part of the Library.
516As a special exception to the GNU Lesser General Public License version 2.1,
517you may distribute such object code incorporating material from header files
518provided with the Open CASCADE Technology libraries (including code of CDL
519generic classes) under terms of your choice, provided that you give
520prominent notice in supporting documentation to this code that it makes use
521of or is based on facilities provided by the Open CASCADE Technology software.