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incorporating your program into proprietary
programs. If your program is a subroutine library,
you may consider it more useful to permit linking
proprietary applications with the library. If this is
what you want to do, use the GNU Lesser Gen-
eral Public License instead of this License.
LGPLv2.1
GNU LESSER GENERAL PUBLIC LICENSE
Version 2.1, February 1999
Copyright (C) 1991, 1999 Free Software Founda-
tion, 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 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 Soft-
ware 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 refer-
ring 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 restric-
tions that forbid distributors to deny you these
rights or to ask you to surrender these rights.
These restrictions translate to certain responsibil-
ities 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 pat-
ent holder. Therefore, we insist that any patent
license obtained for a version of the library must
be consistent with the full freedom of use speci-
fied 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 combina-
tion of the two is legally speaking a combined
work, a derivative of the original library. The or-
dinary 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 pro-
vides 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 pos-
sible use of a certain library, so that it becomes
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