2
To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you
to surrender the ri ghts. These rest rictions transla te to certain respo nsibilities for you if you dis tribute copies of
the software, or i f you modify it.
For example, if you dis tribute copies of such a p rogram, whethe r gratis or for a fee, you mu st give the recipien ts
all the rights that you h ave. You must make sure that they, too, r eceive or can get the source code . And you
must show them these te rms so they know the ir rights.
We protect your rights w ith two steps: (1) copyrigh t the software, a nd (2) offer you this license w hich 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 origi nal authors’ rep utations.
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 clea r that any patent must be l icensed for everyone ’s free use or not licensed at
all.
The precise terms and co nditions for copying , distributi on and modification fo llow.
GNU GENERAL PU BLIC LICENSE
TERMS AND CONDITI ONS FOR COPYING , DISTRIBUT ION AND MODIFIC ATION
0. This Lice nse applies to any program o r other work which contai ns a notice placed by the copyright h older
saying it may be distri buted under the ter ms of this General Pub lic License. The “Pr ogram”, below, refers to
any such program or wor k, and a “work base d on the Program” mea ns either the Prog ram or any derivat ive
work under copyright l aw: that is to say, a work containi ng the Program or a por tion of it, either ver batim
or with modification s and/or translated into a nother language. (Her einafter, translatio n is included without
limitation in the ter m “modification”.) Each l icensee is addresse d as “you”.
Activities other t han copying, distr ibution and modific ation are not covered by th is License; they are ou tside
its scope. The act of r unning the Progr am is not restric ted, and the outp ut from the Progr am is covered only
if its contents const itute a work based on the Pr ogram (independen t of having been made by running t he
Program). Whether th at is true depends o n what the Progra m does.
1. You may copy and dis tribute verba tim copies of the Progr am’s source code as you rece ive it, in any medium ,
provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice
and disclaimer of warr anty; keep intact al l the notices that refer to this L icense and to the absence of any
warranty; and g ive any other recipie nts of the Program a copy of t his License along wi th the Program.
You may charge a fee for the physical a ct of transferri ng a copy, and you may at your option offer w arranty
protection in exchan ge for a fee.
2. You may mod ify your copy or copies of the Pr ogram or any port ion of it, thus forming a w ork based on the
Program, and copy and dis tribute such modi fications or work und er the terms of Sectio n 1 above, provided
that you also meet all of thes e conditions:
a) You must cause the modi fied files to carry pr ominent notices st ating that you changed th e files and the
date of any change.
b) You must c ause any work that you dis tribute or publish, t hat in whole or in part co ntains or is derived
from the Program or a ny part thereof, to be l icensed as a whole at no char ge to all third part ies under
the terms of this License .
c) If th e modified program norm ally reads commands inter actively when run, you m ust cause it, when
started running for such interactive use in the most ordinary way, to print or display an announcement
including an appropr iate copyright notice a nd a notice that there is n o 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 Li cense. (Exception: if t he Program itsel f is interactive bu t 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 P rogram, and can be reas onably considered indepe ndent and separate wor ks in
themselves, then this License, and its terms, do not apply to those sections when you distribute them as
separate works . But when you distr ibute the same sec tions as part of a wh ole which is a work base d on the
Program, the dist ribution of the whole mu st be on the terms of this Lice nse, whose permission s for other
licensees extend to t he entire whole, an d thus to each and ever y part regard less of who wrote it.