GNU LESSER GENERAL PUBLIC LICENSE
Version 2.1, February 1999
Copyright © 1991, 1999 Free Software Foundation, Inc., 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.
GNU LESSER GENERAL PUBLIC LICENSE
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
135