operation manual

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. 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 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 users' 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 program using a
modified version of the Library.
The precise terms and conditions for copying, distribution
and modification follow. Pay close attention to the
difference between a "work based on the library" and a
"work that uses the library". The former contains 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 MODIFICATION
0. This License Agreement applies to any software library
or other program which contains a notice placed by the
copyright holder or other authorized party saying it may
be distributed under the terms of this Lesser General
Public License (also called "this License"). Each licensee
is addressed as "you".
A "library" means a collection of software functions and/or
data prepared so as to be conveniently linked with
application programs (which use some of those functions
and data) to form executables.
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