160
OPEN SOURCE LICENSE
GNU Lesser General Public Li-
cense
Version 2.1, February 1999
Copyright (C) 1991, 1999 Free Software Founda-
tion, Inc. 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA Everyone is permitted to copy
and distribute verbatim copies of this license docu-
ment, 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 ver-
sion 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 explana-
tions 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
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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 restric-
tions that forbid distributors to deny you these
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These restrictions translate to certain responsibili-
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For example, if you distribute copies of the library,
whether gratis or for a fee, you must give the
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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 rec-
ompiling 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,
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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
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Finally, software patents pose a constant threat
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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