22

✏️ Editing: LGPL-2.1-or-later

GNU LESSER GENERAL PUBLIC LICENSE

Version 2.1, February 1999

51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.

[This is the first released version of the Lesser GPL. It also counts
as the successor of the GNU Library Public License, version 2, hence
the version number 2.1.]

Preamble

The licenses for most software are designed to take away your freedom
to share and change it. By contrast, the GNU General Public Licenses are
intended to guarantee your freedom to share and change free software--to
make sure the software is free for all its users.

This license, the Lesser General Public License, applies to some specially
designated software packages--typically libraries--of the Free Software
Foundation and other authors who decide to use it. You can use it too,
but we suggest you first think carefully about whether this license or
the ordinary General Public License is the better strategy to use in
any particular case, based on the explanations below.

When we speak of free software, we are referring to freedom of use,
not price. Our General Public Licenses are designed to make sure that
you have the freedom to distribute copies of free software (and charge
for this service if you wish); that you receive source code or can get it
if you want it; that you can change the software and use pieces of it in
new free programs; and that you are informed that you can do these things.

To protect your rights, we need to make restrictions that forbid
distributors to deny you these rights or to ask you to surrender these
rights. These restrictions translate to certain responsibilities for
you if you distribute copies of the library or if you modify it.

For example, if you distribute copies of the library, whether gratis
or for a fee, you must give the recipients all the rights that we gave
you. You must make sure that they, too, receive or can get the source
code. If you link other code with the library, you must provide complete
object files to the recipients, so that they can relink them with the
library after making changes to the library and recompiling it. And you
must show them these terms so they know their rights.

We protect your rights with a two-step method: (1) we copyright the
library, and (2) we offer you this license, which gives you legal
permission to copy, distribute and/or modify the library.

To protect each distributor, we want to make it very clear that there
is no warranty for the free library. Also, if the library is modified
by someone else and passed on, the recipients should know that what they
have is not the original version, so that the original author's reputation
will not be affected by problems that might be introduced by others.

Finally, software patents pose a constant threat to the existence of
any free program. We wish to make sure that a company cannot effectively
restrict the users of a free program by obtaining a restrictive license
from a patent holder. Therefore, we insist that any patent license
obtained for a version of the library must be consistent with the full
freedom of use specified in this license.

Most GNU software, including some libraries, is covered by the ordinary
GNU General Public License. This license, the GNU Lesser General
Public License, applies to certain designated libraries, and is quite
different from the ordinary General Public License. We use this license
for certain libraries in order to permit linking those libraries into
non-free programs.

When a program is linked with a library, whether statically or using a
shared library, the combination of the two is legally speaking a combined
work, a derivative of the original library. The ordinary General Public
License therefore permits such linking only if the entire combination
fits its criteria of freedom. The Lesser General Public License permits
more lax criteria for linking other code with the library.

We call this license the "Lesser" General Public License because it
does Less to protect the user's freedom than the ordinary General
Public License. It also provides other free software developers Less
of an advantage over competing non-free programs. These disadvantages
are the reason we use the ordinary General Public License for many
libraries. However, the Lesser license provides advantages in certain
special circumstances.

For example, on rare occasions, there may be a special need to encourage
the widest possible use of a certain library, so that it becomes a
de-facto standard. To achieve this, non-free programs must be allowed
to use the library. A more frequent case is that a free library does
the same job as widely used non-free libraries. In this case, there
is little to gain by limiting the free library to free software only,
so we use the Lesser General Public License.

In other cases, permission to use a particular library in non-free
programs enables a greater number of people to use a large body of free
software. For example, permission to use the GNU C Library in non-free
programs enables many more people to use the whole GNU operating system,
as well as its variant, the GNU/Linux operating system.

Although the Lesser General Public License is Less protective of the
users' freedom, it does ensure that the user of a program that is linked
with the Library has the freedom and the wherewithal to run that program
using a modified version of the Library.

The precise terms and conditions for copying, distribution and
modification follow. Pay close attention to the difference between a
"work based on the library" and a "work that uses the library". The
former contains code derived from the library, whereas the latter must
be combined with the library in order to run.

TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

0. This License Agreement applies to any software library or other
   program which contains a notice placed by the copyright holder or
   other authorized party saying it may be distributed under the terms of
   this Lesser General Public License (also called "this License"). Each
   licensee is addressed as "you".

A "library" means a collection of software functions and/or data
   prepared so as to be conveniently linked with application programs
   (which use some of those functions and data) to form executables.

The "Library", below, refers to any such software library or work
   which has been distributed under these terms. A "work based on
   the Library" means either the Library or any derivative work under
   copyright law: that is to say, a work containing the Library or a
   portion of it, either verbatim or with modifications and/or translated
   straightforwardly into another language. (Hereinafter, translation
   is included without limitation in the term "modification".)

"Source code" for a work means the preferred form of the work for
   making modifications to it. For a library, complete source code
   means all the source code for all modules it contains, plus any
   associated interface definition files, plus the scripts used to
   control compilation and installation of the library.

Activities other than copying, distribution and modification are not
   covered by this License; they are outside its scope. The act of running
   a program using the Library is not restricted, and output from such
   a program is covered only if its contents constitute a work based
   on the Library (independent of the use of the Library in a tool for
   writing it). Whether that is true depends on what the Library does
   and what the program that uses the Library does.

1. You may copy and distribute verbatim copies of the Library's
   complete source code as you receive it, in any medium, provided
   that you conspicuously and appropriately publish on each copy an
   appropriate copyright notice and disclaimer of warranty; keep intact
   all the notices that refer to this License and to the absence of any
   warranty; and distribute a copy of this License along with the Library.

You may charge a fee for the physical act of transferring a copy, and
   you may at your option offer warranty protection in exchange for a fee.

2. You may modify your copy or copies of the Library or any portion of
   it, thus forming a work based on the Library, and copy and distribute
   such modifications or work under the terms of Section 1 above,
   provided that you also meet all of these conditions:

a) The modified work must itself be a software library.

b) You must cause the files modified to carry prominent notices
      stating that you changed the files and the date of any change.

c) You must cause the whole of the work to be licensed at no charge
      to all third parties under the terms of this License.

d) If a facility in the modified Library refers to a function or a
      table of data to be supplied by an application program that uses
      the facility, other than as an argument passed when the facility
      is invoked, then you must make a good faith effort to ensure that,
      in the event an application does not supply such function or table,
      the facility still operates, and performs whatever part of its
      purpose remains meaningful.

(For example, a function in a library to compute square roots
   has a purpose that is entirely well-defined independent of
   the application. Therefore, Subsection 2d requires that any
   application-supplied function or table used by this function must
   be optional: if the application does not supply it, the square root
   function must still compute square roots.)

These requirements apply to the modified work as a whole. If
   identifiable sections of that work are not derived from the Library,
   and can be reasonably considered independent and separate works in
   themselves, then this License, and its terms, do not apply to those
   sections when you distribute them as separate works. But when you
   distribute the same sections as part of a whole which is a work
   based on the Library, the distribution of the whole must be on the
   terms of this License, whose permissions for other licensees extend
   to the entire whole, and thus to each and every part regardless of
   who wrote it.

Thus, it is not the intent of this section to claim rights or contest
   your rights to work written entirely by you; rather, the intent is
   to exercise the right to control the distribution of derivative or
   collective works based on the Library.

In addition, mere aggregation of another work not based on the Library
   with the Library (or with a work based on the Library) on a volume
   of a storage or distribution medium does not bring the other work
   under the scope of this License.

3. You may opt to apply the terms of the ordinary GNU General Public
   License instead of this License to a given copy of the Library. To
   do this, you must alter all the notices that refer to this License,
   so that they refer to the ordinary GNU General Public License,
   version 2, instead of to this License. (If a newer version than
   version 2 of the ordinary GNU General Public License has appeared,
   then you can specify that version instead if you wish.) Do not make
   any other change in these notices.

Once this change is made in a given copy, it is irreversible for
   that copy, so the ordinary GNU General Public License applies to all
   subsequent copies and derivative works made from that copy.

This option is useful when you wish to copy part of the code of the
   Library into a program that is not a library.

4. You may copy and distribute the Library (or a portion or derivative
   of it, under Section 2) in object code or executable form under the
   terms of Sections 1 and 2 above provided that you accompany it with
   the complete corresponding machine-readable source code, which must
   be distributed under the terms of Sections 1 and 2 above on a medium
   customarily used for software interchange.

If distribution of object code is made by offering access to copy from
   a designated place, then offering equivalent access to copy the source
   code from the same place satisfies the requirement to distribute the
   source code, even though third parties are not compelled to copy the
   source along with the object code.

5. A program that contains no derivative of any portion of the Library,
   but is designed to work with the Library by being compiled or linked
   with it, is called a "work that uses the Library". Such a work, in
   isolation, is not a derivative work of the Library, and therefore
   falls outside the scope of this License.

However, linking a "work that uses the Library" with the Library
   creates an executable that is a derivative of the Library (because it
   contains portions of the Library), rather than a "work that uses the
   library". The executable is therefore covered by this License. Section
   6 states terms for distribution of such executables.

When a "work that uses the Library" uses material from a header
   file that is part of the Library, the object code for the work may
   be a derivative work of the Library even though the source code is
   not. Whether this is true is especially significant if the work can
   be linked without the Library, or if the work is itself a library. The
   threshold for this to be true is not precisely defined by law.

If such an object file uses only numerical parameters, data structure
   layouts and accessors, and small macros and small inline functions
   (ten lines or less in length), then the use of the object file
   is unrestricted, regardless of whether it is legally a derivative
   work. (Executables containing this object code plus portions of the
   Library will still fall under Section 6.)

Otherwise, if the work is a derivative of the Library, you may
   distribute the object code for the work under the terms of Section
   6. Any executables containing that work also fall under Section 6,
   whether or not they are linked directly with the Library itself.

6. As an exception to the Sections above, you may also combine or link
   a "work that uses the Library" with the Library to produce a work
   containing portions of the Library, and distribute that work under
   terms of your choice, provided that the terms permit modification
   of the work for the customer's own use and reverse engineering for
   debugging such modifications.

You must give prominent notice with each copy of the work that the
   Library is used in it and that the Library and its use are covered
   by this License. You must supply a copy of this License. If the work
   during execution displays copyright notices, you must include the
   copyright notice for the Library among them, as well as a reference
   directing the user to the copy of this License. Also, you must do
   one of these things:

a) Accompany the work with the complete corresponding
      machine-readable source code for the Library including whatever
      changes were used in the work (which must be distributed under
      Sections 1 and 2 above); and, if the work is an executable linked
      with the Library, with the complete machine-readable "work that
      uses the Library", as object code and/or source code, so that the
      user can modify the Library and then relink to produce a modified
      executable containing the modified Library. (It is understood
      that the user who changes the contents of definitions files in the
      Library will not necessarily be able to recompile the application
      to use the modified definitions.)

b) Use a suitable shared library mechanism for linking with the
      Library. A suitable mechanism is one that (1) uses at run time a
      copy of the library already present on the user's computer system,
      rather than copying library functions into the executable, and
      (2) will operate properly with a modified version of the library,
      if the user installs one, as long as the modified version is
      interface-compatible with the version that the work was made with.

c) Accompany the work with a written offer, valid for at least three
      years, to give the same user the materials specified in Subsection
      6a, above, for a charge no more than the cost of performing this
      distribution.

d) If distribution of the work is made by offering access to copy
      from a designated place, offer equivalent access to copy the above
      specified materials from the same place.

e) Verify that the user has already received a copy of these
      materials or that you have already sent this user a copy.

For an executable, the required form of the "work that uses the
   Library" must include any data and utility programs needed for
   reproducing the executable from it. However, as a special exception,
   the materials to be distributed need not include anything that is
   normally distributed (in either source or binary form) with the major
   components (compiler, kernel, and so on) of the operating system on
   which the executable runs, unless that component itself accompanies
   the executable.

It may happen that this requirement contradicts the license
   restrictions of other proprietary libraries that do not normally
   accompany the operating system. Such a contradiction means you
   cannot use both them and the Library together in an executable that
   you distribute.

7. You may place library facilities that are a work based on the
   Library side-by-side in a single library together with other library
   facilities not covered by this License, and distribute such a combined
   library, provided that the separate distribution of the work based on
   the Library and of the other library facilities is otherwise permitted,
   and provided that you do these two things:

a) Accompany the combined library with a copy of the same work based
      on the Library, uncombined with any other library facilities. This
      must be distributed under the terms of the Sections above.

b) Give prominent notice with the combined library of the fact
      that part of it is a work based on the Library, and explaining
      where to find the accompanying uncombined form of the same work.

8. You may not copy, modify, sublicense, link with, or distribute the
   Library except as expressly provided under this License. Any attempt
   otherwise to copy, modify, sublicense, link with, or distribute the
   Library is void, and will automatically terminate your rights under
   this License. However, parties who have received copies, or rights,
   from you under this License will not have their licenses terminated
   so long as such parties remain in full compliance.

9. You are not required to accept this License, since you have not
   signed it. However, nothing else grants you permission to modify
   or distribute the Library or its derivative works. These actions
   are prohibited by law if you do not accept this License. Therefore,
   by modifying or distributing the Library (or any work based on the
   Library), you indicate your acceptance of this License to do so, and
   all its terms and conditions for copying, distributing or modifying
   the Library or works based on it.

10. Each time you redistribute the Library (or any work based on
   the Library), the recipient automatically receives a license from
   the original licensor to copy, distribute, link with or modify the
   Library subject to these terms and conditions. You may not impose
   any further restrictions on the recipients' exercise of the rights
   granted herein. You are not responsible for enforcing compliance by
   third parties with this License.

11. If, as a consequence of a court judgment or allegation of patent
   infringement or for any other reason (not limited to patent issues),
   conditions are imposed on you (whether by court order, agreement
   or otherwise) that contradict the conditions of this License, they
   do not excuse you from the conditions of this License. If you cannot
   distribute so as to satisfy simultaneously your obligations under this
   License and any other pertinent obligations, then as a consequence
   you may not distribute the Library at all. For example, if a patent
   license would not permit royalty-free redistribution of the Library
   by all those who receive copies directly or indirectly through you,
   then the only way you could satisfy both it and this License would
   be to refrain entirely from distribution of the Library.

If any portion of this section is held invalid or unenforceable under
   any particular circumstance, the balance of the section is intended
   to apply, and the section as a whole is intended to apply in other
   circumstances.

It is not the purpose of this section to induce you to infringe any
   patents or other property right claims or to contest validity of
   any such claims; this section has the sole purpose of protecting
   the integrity of the free software distribution system which
   is implemented by public license practices. Many people have made
   generous contributions to the wide range of software distributed
   through that system in reliance on consistent application of that
   system; it is up to the author/donor to decide if he or she is willing
   to distribute software through any other system and a licensee cannot
   impose that choice.

This section is intended to make thoroughly clear what is believed
   to be a consequence of the rest of this License.

12. If the distribution and/or use of the Library is restricted in
   certain countries either by patents or by copyrighted interfaces, the
   original copyright holder who places the Library under this License
   may add an explicit geographical distribution limitation excluding
   those countries, so that distribution is permitted only in or among
   countries not thus excluded. In such case, this License incorporates
   the limitation as if written in the body of this License.

13. The Free Software Foundation may publish revised and/or new
   versions of the Lesser General Public License from time to time. Such
   new versions will be similar in spirit to the present version, but
   may differ in detail to address new problems or concerns.

Each version is given a distinguishing version number. If the Library
   specifies a version number of this License which applies to it and
   "any later version", you have the option of following the terms and
   conditions either of that version or of any later version published
   by the Free Software Foundation. If the Library does not specify a
   license version number, you may choose any version ever published by
   the Free Software Foundation.

14. If you wish to incorporate parts of the Library into other free
   programs whose distribution conditions are incompatible with these,
   write to the author to ask for permission. For software which is
   copyrighted by the Free Software Foundation, write to the Free Software
   Foundation; we sometimes make exceptions for this. Our decision will
   be guided by the two goals of preserving the free status of all
   derivatives of our free software and of promoting the sharing and
   reuse of software generally.

NO WARRANTY

15. BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NO
   WARRANTY FOR THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE
   LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS
   AND/OR OTHER PARTIES PROVIDE THE LIBRARY "AS IS" WITHOUT WARRANTY OF
   ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
   THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE
   LIBRARY IS WITH YOU. SHOULD THE LIBRARY PROVE DEFECTIVE, YOU ASSUME
   THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

16. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO
   IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY
   MODIFY AND/OR REDISTRIBUTE THE LIBRARY AS PERMITTED ABOVE, BE LIABLE
   TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR
   CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE
   THE LIBRARY (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
   RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR
   A FAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN
   IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
   SUCH DAMAGES. END OF TERMS AND CONDITIONS

How to Apply These Terms to Your New Libraries

If you develop a new library, and you want it to be of the greatest
possible use to the public, we recommend making it free software that
everyone can redistribute and change. You can do so by permitting
redistribution under these terms (or, alternatively, under the terms of
the ordinary General Public License).

To apply these terms, attach the following notices to the library. It is
safest to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least the
"copyright" line and a pointer to where the full notice is found.

This library is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.

This library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

Also add information on how to contact you by electronic and paper mail.

You should also get your employer (if you work as a programmer) or
your school, if any, to sign a "copyright disclaimer" for the library,
if necessary. Here is a sample; alter the names:

Yoyodyne, Inc., hereby disclaims all copyright interest in

the library `Frob' (a library for tweaking knobs) written

by James Random Hacker.

< signature of Ty Coon > , 1 April 1990

Ty Coon, President of Vice

That's all there is to it!

MR SKB