- 14 -
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
