operation manual

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
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.
The "Library", below, refers to any such software
library or work which has been distributed under
these terms. A "work based on the Library" means
either the Library or any derivative work under
copyright law: that is to say, a work containing the
Library or a portion of it, either verbatim or with
modifications and/or translated straightforwardly into
another language. (Hereinafter, translation is included
without limitation in the term "modification".)
"Source code" for a work means the preferred form of
the work for making modifications to it. For a library,
complete source code means all the source code for
all modules it contains, plus any associated interface
definition files, plus the scripts used to control
compilation and installation of the library.
Activities other than copying, distribution and
modification are not covered by this License; they are
outside its scope. The act of running a program using
the Library is not restricted, and output from such a
program is covered only if its contents constitute a
work based on the Library (independent of the use of
the Library in a tool for writing it). Whether that is true
depends on what the Library does and what the
program that uses the Library does.
You may charge a fee for the physical act of
transferring a copy, and you may at your option offer
warranty protection in exchange for a fee.
?a) The modified work must itself be a software
library.
?b) You must cause the files modified to carry
prominent notices stating that you changed the files
and the date of any change.
?c) You must cause the whole of the work to be
licensed at no charge to all third parties under the
terms of this License.
?d) If a facility in the modified Library refers to a
function or a table of data to be supplied by an
application program that uses the facility, other than
as an argument passed when the facility is invoked,
then you must make a good faith effort to ensure that,
in the event an application does not supply such
function or table, the facility still operates, and
performs whatever part of its purpose remains
meaningful.
(For example, a function in a library to compute
square roots has a purpose that is entirely well-
defined independent of the application. Therefore,
Subsection 2d requires that any application-supplied
function or table used by this function must be
optional: if the application does not supply it, the
square root function must still compute square roots.)
These requirements apply to the modified work as a
whole. If identifiable sections of that work are not
derived from the Library, and can be reasonably
considered independent and separate works in
themselves, then this License, and its terms, do not
apply to those sections when you distribute them as
separate works. But when you distribute the same
sections as part of a whole which is a work based on
the Library, the distribution of the whole must be on
the terms of this License, whose permissions for other
licensees extend to the entire whole, and thus to
each and every part regardless of who wrote it.
Thus, it is not the intent of this section to claim rights
or contest your rights to work written entirely by you;
rather, the intent is to exercise the right to control the
distribution of derivative or collective works based on
the Library.
In addition, mere aggregation of another work not
based on the Library with the Library (or with a work
based on the Library) on a volume of a storage or
distribution medium does not bring the other work
under the scope of this License.
Once this change is made in a given copy, it is
irreversible for that copy, so the ordinary GNU
General Public License applies to all subsequent
copies and derivative works made from that copy.
This option is useful when you wish to copy part of
the code of the Library into a program that is not a
library.
If distribution of object code is made by offering
92