To use this license in source code, put one of the following SPDX
tag/value pairs into a comment according to the placement
guidelines in the licensing rules documentation.
For 'GNU Library General Public License (LGPL) version 2.0 only' use:
For 'GNU Library General Public License (LGPL) version 2.0 or any later
GNU LIBRARY GENERAL PUBLIC LICENSE
Version 2, June 1991
Copyright (C) 1991 Free Software Foundation, Inc.
51 Franklin St, 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 library GPL. It is numbered 2
because it goes with version 2 of the ordinary GPL.]
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 Library General Public License, applies to some specially
designated Free Software Foundation software, and to any other libraries
whose authors decide to use it. You can use it for your libraries, too.
When we speak of free software, we are referring to freedom, 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 or use pieces of it in new free programs; and that
you know you can do these things.
To protect your rights, we need to make restrictions that forbid anyone to
deny you these rights or to ask you to surrender the 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 a program 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.
Our method of protecting your rights has two steps: (1) copyright the
library, and (2) offer you this license which gives you legal permission to
copy, distribute and/or modify the library.
Also, for each distributor's protection, we want to make certain that
everyone understands that there is no warranty for this free library. If
the library is modified by someone else and passed on, we want its
recipients to know that what they have is not the original version, so that
any problems introduced by others will not reflect on the original authors'
Finally, any free program is threatened constantly by software patents. We
wish to avoid the danger that companies distributing free software will
individually obtain patent licenses, thus in effect transforming the
program into proprietary software. To prevent this, we have made it clear
that any patent must be licensed for everyone's free use or not licensed at
Most GNU software, including some libraries, is covered by the ordinary GNU
General Public License, which was designed for utility programs. This
license, the GNU Library General Public License, applies to certain
designated libraries. This license is quite different from the ordinary
one; be sure to read it in full, and don't assume that anything in it is
the same as in the ordinary license.
The reason we have a separate public license for some libraries is that
they blur the distinction we usually make between modifying or adding to a
program and simply using it. Linking a program with a library, without
changing the library, is in some sense simply using the library, and is
analogous to running a utility program or application program. However, in
a textual and legal sense, the linked executable is a combined work, a
derivative of the original library, and the ordinary General Public License
treats it as such.
Because of this blurred distinction, using the ordinary General Public
License for libraries did not effectively promote software sharing, because
most developers did not use the libraries. We concluded that weaker
conditions might promote sharing better.
However, unrestricted linking of non-free programs would deprive the users
of those programs of all benefit from the free status of the libraries
themselves. This Library General Public License is intended to permit
developers of non-free programs to use free libraries, while preserving
your freedom as a user of such programs to change the free libraries that
are incorporated in them. (We have not seen how to achieve this as regards
changes in header files, but we have achieved it as regards changes in the
actual functions of the Library.) The hope is that this will lead to faster
development of free libraries.
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, while the latter only works together with the
Note that it is possible for a library to be covered by the ordinary
General Public License rather than by this special one.
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. This License Agreement applies to any software library which contains a
notice placed by the copyright holder or other authorized party saying
it may be distributed under the terms of this Library General Public
License (also called "this License"). Each licensee is addressed as
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
(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
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 compile 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
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) 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
c) 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.
d) 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 source code
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 to 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
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
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 Library 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
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.
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.
one line to give the library's name and an idea of what it does.
Copyright (C) year name of author
This library is free software; you can redistribute it and/or modify it
under the terms of the GNU Library General Public License as published by
the Free Software Foundation; either version 2 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 Library General Public
License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; if not, write to the Free Software Foundation,
Inc., 51 Franklin St, 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!