117
Preamble
The licenses for most software are designed to take away your freedom to share and change it.
By contrast, the GNU General Public Licenses are intended to guarantee your freedom to
share and change free software to make sure the software is free for all its users.
This license, 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 suggest you first think carefully about whether this license or
the ordinary General Public License is the better strategy to use in any particular case, based
on the explanations below.
When we speak of free software, we are referring to freedom of use, not price. Our General
Public Licenses are designed to make sure that you have the freedom to distribute copies of
free software (and charge for this service if you wish); that you receive source code or can get
it if you want it; that you can change the software and use pieces of it in new free programs;
and that you are informed that you can do these things.
To protect your rights, we need to make restrictions that forbid distributors to deny you these
rights or to ask you to surrender these rights. These restrictions translate to certain
responsibilities for you if you distribute copies of the library or if you modify it.
For example, if you distribute copies of the library, whether gratis or for a fee, you must give
the recipients all the rights that we gave you. You must make sure that they, too, receive or can
get the source code. If you link other code with the library, you must provide complete object
files to the recipients, so that they can relink them with the library after making changes to the
library and recompiling it. And you must show them these terms so they know their rights.
We protect your rights with a two-step method: (1) we copyright the library, and (2) we offer you
this license, which gives you legal permission to copy, distribute and/or modify the library.
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.
