AppendixE. License Conditions
Preamble
Thelicenses for most software are designed to take away your freedom to share and change it. By contrast, the
GNUGeneral Public Licenses are intended to guarantee your freedom to share and change free software--to make
surethe software is free for all its users.
Thislicense, 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
suggestyou first think carefully about whether this license or the ordinary General Public License is the better
strategyto use in any particular case, based on the explanations below.
Whenwe speak of free software, we are referring to freedom of use, not price. Our General Public Licenses are
designedto make sure that you have the freedom to distribute copies of free software (and charge for this service if
youwish); that you receive source code or can get it if you want it; that you can change the software and use pieces
ofit in new free programs; and that you are informed that you can do these things.
Toprotect your rights, we need to make restrictions that forbid distributors to deny you these rights or to ask you to
surrenderthese rights. These restrictions translate to certain responsibilities for you if you distribute copies of the
libraryor if you modify it.
Forexample, if you distribute copies of the library, whether gratis or for a fee, you must give the recipients all the
rightsthat we gave you. You must make sure that they,too, receive or can get the source code. If you link other code
withthe library, you must provide complete object files to the recipients, so that they can relink them with the
libraryafter making changes to the library and recompiling it. And you must show them these terms so they know
theirrights.
Weprotect your rights with a two-step method: (1) we copyright the library, and (2) we offer you this license, which
givesyou legal permission to copy, distribute and/or modify the library.
Toprotect each distributor, we want to make it very clear that there is no warranty for the free library.Also, if the
libraryis 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
companycannot 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
fullfreedom of use specified in this license.
MostGNU 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
theordinary General Public License. We use this license for certain libraries in order to permit linking those
librariesinto non-free programs.
Whena program is linked with a library, whether statically or using a shared library, the combination of the two is
legallyspeaking a combined work, a derivative of the original library. The ordinary General Public License
thereforepermits such linking only if the entire combination fits its criteria of freedom. The Lesser General Public
Licensepermits more lax criteria for linking other code with the library.
Wecall this license the "Lesser" General Public License because it does Less to protect the user’s freedom than the
ordinaryGeneral Public License. It also provides other free software developers Less of an advantage over
competingnon-free programs. These disadvantages are the reason we use the ordinary General Public License for
manylibraries. However, the Lesser license provides advantages in certain special circumstances.
Forexample, 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.
Amore frequent case is that a free library does the same job as widely used non-free libraries. In this case, there is
littleto gain by limiting the free library to free software only, so we use the Lesser General Public License.
Inother cases, permission to use a particular library in non-free programs enables a greater number of people to use
alarge body of free software. For example, permission to use the GNU C Library in non-free programs enables
manymore people to use the whole GNU operating system, as well as its variant, the GNU/Linux operating system.
Althoughthe Lesser General Public License is Less protective of the users’ freedom, it does ensure that the user of
aprogram that is linked with the Library has the freedom and the wherewithal to run that program using a modified
versionof the Library.
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