User Manual

21
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.
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.
1. You may copy and distribute verbatim copies of the Library's complete source code
as you receive it, in any medium, provided that you conspicuously and appropriately
publish on each copy an appropriate copyright notice and disclaimer of warranty;
keep intact all the notices that refer to this License and to the absence of any
warranty; and distribute a copy of this License along with the Library.
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.
2. You may modify your copy or copies of the Library or any portion of it, thus forming
a work based on the Library, and copy and distribute such modifications or work
under the terms of Section 1 above, provided that you also meet all of these
conditions:
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