= GNU General Public License

Free Software Foundation

Version 2, June 1991

Copyright (C) 1989, 1991 Free Software Foundation, Inc.  675 Mass Ave,

Cambridge, MA 02139, USA

Everyone is permitted to copy and distribute verbatim copies of this

license document, but changing it is not allowed.

[[licenses-gpl-0]]

== Preamble

The licenses for most software are designed to take away your freedom

to share and change it.  By contrast, the GNU General Public License

is intended to guarantee your freedom to share and change free

software--to make sure the software is free for all its users.  This

General Public License applies to most of the Free Software

Foundation's software and to any other program whose authors commit to

using it.  (Some other Free Software Foundation software is covered by

the GNU Library General Public License instead.)  You can apply it to

your programs, too.

When we speak of free software, we are referring to freedom, 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 or use pieces of it

in new free programs; and that you know you can do these things.

To protect your rights, we need to make restrictions that forbid

anyone to deny you these rights or to ask you to surrender the rights.

These restrictions translate to certain responsibilities for you if

you distribute copies of the software, or if you modify it.

For example, if you distribute copies of such a program, whether

gratis or for a fee, you must give the recipients all the rights that

you have.  You must make sure that they, too, receive or can get the

source code.  And you must show them these terms so they know their

rights.

We protect your rights with two steps:

1. copyright the software, and 

2. offer you this license which gives you legal permission to copy,

distribute and/or modify the software.

Also, for each author's protection and ours, we want to make certain

that everyone understands that there is no warranty for this free

software.  If the software is modified by someone else and passed on,

we want its recipients to know that what they have is not the

original, so that any problems introduced by others will not reflect

on the original authors' reputations.

Finally, any free program is threatened constantly by software

patents.  We wish to avoid the danger that redistributors of a free

program will individually obtain patent licenses, in effect making the

program proprietary.  To prevent this, we have made it clear that any

patent must be licensed for everyone's free use or not licensed at

all.

The precise terms and conditions for copying, distribution and

modification follow.

[[licenses-gpl-1]]

== Terms and Conditions for Copying, Distribution and Modification

[[licenses-gpl-1-0]]

=== Section 0

This License applies to any program or other work which contains a

notice placed by the copyright holder saying it may be distributed

under the terms of this General Public License.  The ``Program'',

below, refers to any such program or work, and a ``work based on the

Program'' means either the Program or any derivative work under

copyright law: that is to say, a work containing the Program or a

portion of it, either verbatim or with modifications and/or translated

into another language.  (Hereinafter, translation is included without

limitation in the term ``modification''.)  Each licensee is addressed

as ``you''.

Activities other than copying, distribution and modification are not

covered by this License; they are outside its scope.  The act of

running the Program is not restricted, and the output from the Program

is covered only if its contents constitute a work based on the

Program (independent of having been made by running the Program).

Whether that is true depends on what the Program does.

[[licenses-gpl-1-1]]

=== Section 1

You may copy and distribute verbatim copies of the Program's 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 give any other

recipients of the Program a copy of this License along with the

Program.

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.

[[licenses-gpl-1-2]]

=== Section 2

You may modify your copy or copies of the Program or any portion of

it, thus forming a work based on the Program, and copy and distribute

such modifications or work under the terms of <<licenses-gpl-1-1>>

above, provided that you also meet all of these conditions:

a. You must cause the modified files to carry prominent notices

stating that you changed the files and the date of any change.

b. You must cause any work that you distribute or publish, that in

whole or in part contains or is derived from the Program or any part

thereof, to be licensed as a whole at no charge to all third parties

under the terms of this License.

c. If the modified program normally reads commands interactively when

run, you must cause it, when started running for such interactive use

in the most ordinary way, to print or display an announcement

including an appropriate copyright notice and a notice that there is

no warranty (or else, saying that you provide a warranty) and that

users may redistribute the program under these conditions, and telling

the user how to view a copy of this License.

[NOTE]

.Exception

======================================================================

If the Program itself is interactive but does not normally print such

an announcement, your work based on the Program is not required to

print an announcement.

======================================================================

These requirements apply to the modified work as a whole.  If

identifiable sections of that work are not derived from the Program,

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 Program, 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 Program.

In addition, mere aggregation of another work not based on the Program

with the Program (or with a work based on the Program) on a volume of

a storage or distribution medium does not bring the other work under

the scope of this License.

[[licenses-gpl-1-3]]

=== Section 3

You may copy and distribute the Program (or a work based on it, under

<<licenses-gpl-1-2>>) in object code or executable form under the

terms of <<licenses-gpl-1-1>> and <<licenses-gpl-1-2>> above provided

that you also do one of the following:

a. Accompany it with the complete corresponding machine-readable

source code, which must be distributed under the terms of

<<licenses-gpl-1-1>> and <<licenses-gpl-1-2>> above on a medium

customarily used for software interchange; or,

b. Accompany it with a written offer, valid for at least three years,

to give any third party, for a charge no more than your cost of

physically performing source distribution, a complete machine-readable

copy of the corresponding source code, to be distributed under the

terms of <<licenses-gpl-1-1>> and <<licenses-gpl-1-2>> above on a

medium customarily used for software interchange; or,

c. Accompany it with the information you received as to the offer to

distribute corresponding source code.  (This alternative is allowed

only for noncommercial distribution and only if you received the

program in object code or executable form with such an offer, in

accord with Subsection b above.)

The source code for a work means the preferred form of the work for

making modifications to it.  For an executable work, 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 executable.  However, as a

special exception, the source code distributed need not include

anything that is normally distributed (in either source or binary

form) with the major components (compiler, kernel, and so on) of the

operating system on which the executable runs, unless that component

itself accompanies the executable.

If distribution of executable or 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 counts as

distribution of the source code, even though third parties are not

compelled to copy the source along with the object code.

[[licenses-gpl-1-4]]

=== Section 4

You may not copy, modify, sublicense, or distribute the Program except

as expressly provided under this License.  Any attempt otherwise to

copy, modify, sublicense or distribute the Program is void, and will

automatically terminate your rights under this License.  However,

parties who have received copies, or rights, from you under this

License will not have their licenses terminated so long as such

parties remain in full compliance.

[[licenses-gpl-1-5]]

=== Section 5

You are not required to accept this License, since you have not signed

it.  However, nothing else grants you permission to modify or

distribute the Program or its derivative works.  These actions are

prohibited by law if you do not accept this License.  Therefore, by

modifying or distributing the Program (or any work based on the

Program), you indicate your acceptance of this License to do so, and

all its terms and conditions for copying, distributing or modifying

the Program or works based on it.

[[licenses-gpl-1-6]]

=== Section 6

Each time you redistribute the Program (or any work based on the

Program), the recipient automatically receives a license from the

original licensor to copy, distribute or modify the Program subject to

these terms and conditions.  You may not impose any further

restrictions on the recipients' exercise of the rights granted herein.

You are not responsible for enforcing compliance by third parties to

this License.

[[licenses-gpl-1-7]]

=== Section 7

If, as a consequence of a court judgment or allegation of patent

infringement or for any other reason (not limited to patent issues),

conditions are imposed on you (whether by court order, agreement or

otherwise) that contradict the conditions of this License, they do not

excuse you from the conditions of this License.  If you cannot

distribute so as to satisfy simultaneously your obligations under this

License and any other pertinent obligations, then as a consequence you

may not distribute the Program at all.  For example, if a patent

license would not permit royalty-free redistribution of the Program by

all those who receive copies directly or indirectly through you, then

the only way you could satisfy both it and this License would be to

refrain entirely from distribution of the Program.

If any portion of this section is held invalid or unenforceable under

any particular circumstance, the balance of the section is intended to

apply and the section as a whole is intended to apply in other

circumstances.

It is not the purpose of this section to induce you to infringe any

patents or other property right claims or to contest validity of any

such claims; this section has the sole purpose of protecting the

integrity of the free software distribution system, which is

implemented by public license practices.  Many people have made

generous contributions to the wide range of software distributed

through that system in reliance on consistent application of that

system; it is up to the author/donor to decide if he or she is willing

to distribute software through any other system and a licensee cannot

impose that choice.

This section is intended to make thoroughly clear what is believed to

be a consequence of the rest of this License.

[[licenses-gpl-1-8]]

=== Section 8

If the distribution and/or use of the Program is restricted in certain

countries either by patents or by copyrighted interfaces, the original

copyright holder who places the Program under this License may add an

explicit geographical distribution limitation excluding those

countries, so that distribution is permitted only in or among

countries not thus excluded.  In such case, this License incorporates

the limitation as if written in the body of this License.

[[licenses-gpl-1-9]]

=== Section 9

The Free Software Foundation may publish revised and/or new versions

of the General Public License from time to time.  Such new versions

will be similar in spirit to the present version, but may differ in

detail to address new problems or concerns.

Each version is given a distinguishing version number.  If the Program

specifies a version number of this License which applies to it and

``any later version'', you have the option of following the terms and

conditions either of that version or of any later version published by

the Free Software Foundation.  If the Program does not specify a

version number of this License, you may choose any version ever

published by the Free Software Foundation.

[[licenses-gpl-1-10]]

=== Section 10

If you wish to incorporate parts of the Program into other free

programs whose distribution conditions are different, write to the

author to ask for permission.  For software which is copyrighted by

the Free Software Foundation, write to the Free Software Foundation;

we sometimes make exceptions for this.  Our decision will be guided by

the two goals of preserving the free status of all derivatives of our

free software and of promoting the sharing and reuse of software

generally.

[[licenses-gpl-1-11]]

=== NO WARRANTY

*Section 11*

BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY

FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT

WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER

PARTIES PROVIDE THE PROGRAM ``AS IS'' WITHOUT WARRANTY OF ANY KIND,

EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE

IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE

PROGRAM IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME

THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

[[licenses-gpl-1-12]]

=== Section 12

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING

WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR

REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR

DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL

DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM

(INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED

INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF

THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER

OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

_End of Terms and Conditions._

[[licenses-gpl-2]]

== Appendix A. How to Apply These Terms to Your New Programs

If you develop a new program, and you want it to be of the greatest

possible use to the public, the best way to achieve this is to make it

free software which everyone can redistribute and change under these

terms.

To do so, attach the following notices to the program.  It is safest

to attach them to the start of each source file to most effectively

convey the exclusion of warranty; and each file should have at least

the <quote>copyright</quote> line and a pointer to where the full

notice is found.

----------------------------------------------------------------------

<one line to give the program's name and a brief idea of what it does.>

Copyright (C) 19yy  <name of author>

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

----------------------------------------------------------------------

Also add information on how to contact you by electronic and paper

mail.

If the program is interactive, make it output a short notice like this

when it starts in an interactive mode:

----------------------------------------------------------------------

Gnomovision version 69, Copyright (C) 19yy name of author

Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.

This is free software, and you are welcome to redistribute it

under certain conditions; type `show c' for details.

----------------------------------------------------------------------

The hypothetical commands `show w' and `show c' should show the

appropriate parts of the General Public License.  Of course, the

commands you use may be called something other than `show w' and `show

c'; they could even be mouse-clicks or menu items--whatever suits your

program.

You should also get your employer (if you work as a programmer) or

your school, if any, to sign a ``copyright disclaimer'' for

the program, if necessary.  Here is a sample; alter the names:

----------------------------------------------------------------------

Yoyodyne, Inc., hereby disclaims all copyright interest in the program

`Gnomovision' (which makes passes at compilers) written by James Hacker.

<signature of Ty Coon>, 1 April 1989

Ty Coon, President of Vice

----------------------------------------------------------------------

This General Public License does not permit incorporating your program

into proprietary programs.  If your program is a subroutine library,

you may consider it more useful to permit linking proprietary

applications with the library.  If this is what you want to do, use

the GNU Library General Public License instead of this License.