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APPENDIX
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P
EN
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IX
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 cop-
ies 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 strat-
egy to use in any particular case, based on the explana-
tions below.
When we speak of free software, we are referring to free-
dom of use, not price. Our General Public Licenses are
designed to make sure that you have the freedom to dis-
tribute 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 copy-
right the library, and (2) we offer you this license, which
gives you legal permission to copy, distribute and/or mod-
ify 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 exis-
tence of any free program. We wish to make sure that a
company cannot effectively restrict the users of a free pro-
gram 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 des-
ignated 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 origi-
nal 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 com-
peting non-free programs. These disadvantages are the
reason we use the ordinary General Public License for
many libraries. However, the Lesser license provides advan-
tages 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
