Licenses
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 nonfree 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
nonfree 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 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.
3. You may opt to apply the terms of the ordinary GNU
General Public License instead of this License to a
given copy of the Library. To do this, you must alter
all the notices that refer to this License, so that they
refer to the ordinary GNU General Public License,
version 2, instead of to this License. (If a newer
version than version 2 of the ordinary GNU General
Public License has appeared, then you can specify
that version instead if you wish.) Do not make any
other change in these notices.
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.
4. You may copy and distribute the Library (or a
portion or derivative of it, under Section 2) in
object code or executable form under the terms
of Sections 1 and 2 above provided that you
accompany it with the complete corresponding
machine-readable source code, which must be
distributed under the terms of Sections 1 and 2
above on a medium customarily used for software
interchange.
If distribution of object code is made by offering
access to copy from a designated place, then
offering equivalent access to copy the source code
from the same place satisfies the requirement to
distribute the source code, even though third parties
are not compelled to copy the source along with the
object code.
5. A program that contains no derivative of any portion
of the Library, but is designed to work with the
Library by being compiled or linked with it, is called
a “work that uses the Library”. Such a work, in
isolation, is not a derivative work of the Library, and
therefore falls outside the scope of this License.
However, linking a “work that uses the Library” with
the Library creates an executable that is a derivative
of the Library (because it contains portions of the
Library), rather than a “work that uses the library”.
The executable is therefore covered by this License.
Section 6 states terms for distribution of such
executables.
When a “work that uses the Library” uses material
from a header file that is part of the Library, the
object code for the work may be a derivative work
of the Library even though the source code is not.
Whether this is true is especially significant if the
work can be linked without the Library, or if the work
is itself a library. The threshold for this to be true is
not precisely defined by law.
If such an object file uses only numerical
parameters, data structure layouts and accessors,
and small macros and small inline functions (ten
lines or less in length), then the use of the object file
is unrestricted, regardless of whether it is legally a
derivative work. (Executables containing this object
code plus portions of the Library will still fall under
Section 6.)
Otherwise, if the work is a derivative of the Library,
you may distribute the object code for the work
under the terms of Section 6. Any executables
containing that work also fall under Section 6,
whether or not they are linked directly with the
Library itself.
6. As an exception to the Sections above, you may
also combine or link a “work that uses the Library”
with the Library to produce a work containing
portions of the Library, and distribute that work
under terms of your choice, provided that the terms
permit modification of the work for the customer’s
BDP-121̲License̲en.indd 3
BDP-121̲License̲en.indd 3
2009/04/16 17:38:16
2009/04/16 17:38:16
