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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 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 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 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 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 on the library” and a “work that uses the library”. The former contains code
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GNU LESSER GENERAL PUBLIC LICENSE
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
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