2
To protect your rights, we n eed to make restr ictions that forb id anyone to deny you thes e rights or to ask you
to surrender the r ights. These res trictions tr anslate to cert ain responsibil ities for you if you dis tribute copies of
the software, or i f you modify it.
For example, if you dis tribute copies of su ch a program, whe ther gratis or for a fee , you must give the re cipients
all the rights that you h ave. You must make sure that t hey, too, receive or can ge t the source code. And yo u
must show them these te rms so they know the ir rights.
We protect your rights w ith two steps: (1) copyr ight the softwa re, and (2) offer you thi s license which gives you
legal permission to co py, distribute and /or modify the soft ware.
Also, for each author’s p rotection and our s, we want to make cer tain that ever yone underst ands that there
is no warranty for th is free softwa re. If the softw are is modied by some one else and passed o n, we want its
recipients to know th at what they have is not the o riginal, so that any p roblems introd uced by others will not
reect on the origi nal authors’ rep utations.
Finally, any free progr am is threatened con stantly by soft ware patents . We wish to avoid the danger th at
redistributor s of a free progra m will individuall y obtain patent lice nses, in effect ma king the progra m proprietar y.
To prevent this, we have made it cle ar that any patent mus t be licensed for ever yone’s free use or not lice nsed
at all.
The precise terms an d conditions for copying , distributi on and modicatio n follow.
GNU GENERAL PU BLIC LICENSE
TERMS AND CONDIT IONS FOR COPYING , DISTRIBU TION AND MODIFI CATION
0. This Li cense applies to any pr ogram or other wor k which contains a noti ce placed by the copyrigh t holder
saying it may be distri buted under the te rms of this Gener al Public License. T he “Program”, below, r efers to
any such program or wor k, and a “work bas ed on the Program” me ans either the Pro gram or any deriv ative
work under copyrigh t law: that is to say, a work cont aining the Progr am or a portion of it , either verba tim
or with modication s and/or translate d into another langua ge. (Hereinaf ter, translation is i ncluded without
limitation in the ter m “modication”.) Each l icensee is addresse d as “you”.
Activities other t han copying, distr ibution and modi cation are not cover ed by this License; th ey are outside
its scope. The act of r unning the Progr am is not restric ted, and the outpu t from the Progr am is covered
only if its contents con stitute a work ba sed on the Program ( independent of hav ing been made by runn ing
the Program). Whethe r that is true depe nds on what the Progr am does.
1. You may copy and dis tribute ver batim copies of the Prog ram’s source code as you r eceive it, in any med ium,
provided that you conspi cuously and approp riately publish o n each copy an appropr iate copyright notice
and disclaimer of warr anty; keep int act all the notices t hat refer to this Licen se and to the absence of any
warranty; and g ive any other recipie nts of the Progra m a copy of this License along w ith the Program .
You may charge a fee for the physical a ct of transfer ring a copy, and you may at your opti on offer warra nty
protection in exchan ge for a fee.
2. You may modify your copy or copies of the P rogram or any por tion of it, thus for ming a work based on t he
Program, and copy and di stribute such m odications or wor k under the terms of S ection 1 above, pr ovided
that you also meet all of thes e conditions:
a) You must cause t he modied les to car ry prominen t notices stating th at you changed the les a nd the
date of any change.
b) You must cause any work t hat you distribu te or publish, that i n whole or in part con tains or is derive d
from the Program or a ny part thereof, t o be licensed as a whole a t no charge to all third p arties under
the terms of this Licens e.
c) If the modi ed program nor mally reads comman ds interactiv ely when run, you mu st cause it, when
started run ning for such intera ctive use in the most o rdinary way, to pri nt or display an announ cement
including an appropr iate copyright not ice and a notice that ther e is no warrant y (or else, saying that you
provide a warrant y) and that users may r edistribute t he program unde r these conditions , and telling
the user how to view a copy of this L icense. (Exceptio n: if the Program i tself is interac tive but does not
normally print suc h an announcement , your work based on the P rogram is not requ ired to print an
announcement.)
These requireme nts apply to the modi ed work as a whole. I f identiable sec tions of that work ar e
not derived from the P rogram, and can b e reasonably consi dered independ ent and separate wo rks in
themselves, then t his License, and it s terms, do not appl y to those sections wh en you distribu te them as
separate works . But when you dist ribute the same s ections as par t of a whole which is a work b ased on the
Program, the dist ribution of the w hole must be on the ter ms of this License, w hose permissions fo r other
licensees extend to t he entire whole, a nd thus to each and ever y part regar dless of who wrote it .