User's Guide

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 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
171