User Manual

Finally, software patents pose a constant threat to the existence of an
y free program. We wish to make sure that a company cannot effectiv
ely restrict the users of a free program by obtaining a restrictive licens
e from a patent holder. Therefore, we insist that any patent license ob
tained for a version of the library must be consistent with the full freed
om of use specified in this license.
Most GNU software, including some libraries, is covered by the ordinar
y GNU General Public License. This license, the GNU Lesser General Pu
blic License, applies to certain designated libraries, and is quite differe
nt from the ordinary General Public License. We use this license for cer
tain libraries in order to permit linking those libraries into non-free pro
grams.
When a program is linked with a library, whether statically or using a s
hared library, the combination of the two is legally speaking a combine
d work, a derivative of the original library. The ordinary General Public
License therefore permits such linking only if the entire combination fit
s its criteria of freedom. The Lesser General Public License permits mo
re 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 Lic
ense. It also provides other free software developers Less of an advant
age over competing non-free programs. These disadvantages are the r
eason we use the ordinary General Public License for many libraries. H
owever, the Lesser license provides advantages in certain special circu
mstances.
For example, on rare occasions, there may be a special need to encour
age the widest possible use of a certain library, so that it becomes a d
e-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 t
o 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 progr
ams enables a greater number of people to use a large body of free so
ftware. 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 us
ers' 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 prog
ram using a modified version of the Library.
The precise terms and conditions for copying, distribution and modifica
tion follow. Pay close attention to the difference between a "work base
d on the library" and a "work that uses the library". The former contai
ns code derived from the library, whereas the latter must be combined
with the library in order to run.
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFI
CATION
0. This License Agreement applies to any software library or other pro
gram which contains a notice placed by the copyright holder or other a