GNU Lesser General Public License (LGPL)
Version 2.1, February 1999
Copyright (C) 1991, 1999 Free Software Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 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
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 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
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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
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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
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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
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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
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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,
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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 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 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.
Although the Lesser General Public License is Less protective of the users' freedom, it does ensure that the user of a program that is linked with the
Library has the freedom and the wherewithal to run that program using a modified version of the Library.
The precise terms and conditions for copying, distribution and modification follow. Pay close attention to the difference between a "work based
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TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. This License Agreement applies to any software library or other program which contains a notice placed by the copyright holder or other
authorized party saying it may be distributed under the terms of this Lesser General Public License (also called "this License"). Each licensee is
addressed as "you".