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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 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
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
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is that a free library does the same job as widely
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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
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The precise terms and conditions for copying,
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GNU LESSER GENERAL
PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING,
DISTRIBUTION AND MODIFICATION
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