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End User License Agreements for Operating System
Software
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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 guar-
antee 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, ap-
plies 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 soft-
ware 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 dis-
tribute 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 com-
plete 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 li-
cense, which gives you legal permission to copy, dis-
tribute 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 us-
ers 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 cov-
ered by the ordinary GNU General Public License. This
license, the GNU Lesser General Public License, ap-
plies to certain designated libraries, and is quite differ-
ent from the ordinary General Public License. We use
this license for certain libraries in order to permit link-
ing 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 deriva-
tive 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 Li-
cense because it does Less to protect the user's free-
dom than the ordinary General Public License. It also
provides other free software developers Less of an ad-
vantage over competing nonfree programs. These dis-
advantages are the reason we use the ordinary General
Public License for many libraries. However, the Lesser
license provides advantages in certain special circum-
stances.
For example, on rare occasions, there may be a spe-
cial need to encourage the widest possible use of a cer-
tain 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 li-
brary does the same job as widely used non-free librar-
ies. In this case, there is little to gain by limiting the free
library to free software only, so we use the Lesser Gen-
eral Public License.
In other cases, permission to use a particular library
in non-free programs enables a greater number of peo-
ple to use a large body of free software. For example,
permission to use the GNU C Library in non-free pro-
grams enables many more people to use the whole
GNU LESSER GENERAL PUBLIC LICENSE Version 2.1, February 1999
Copyright© 1991, 1999 Free Software Foundation, Inc. 51 Franklin St, 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 Li-
cense, version 2, hence the version number 2.1.]
