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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.
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
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