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APPENDIX
141
Copyright (C) 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, ver-
sion 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 careful-
ly 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 soft-
ware (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 mod-
ified by someone else and passed on, the recipients should know
that what they have is not the original version, so that the origi-
nal 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 can-
not 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 per-
mit 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 devel-
opers 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 pro-
vides 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.
GNU LESSER GENERAL PUBLIC LICENSE
Version 2.1, February 1999