2
To protect your right s, we need to make res trictions that fo rbid anyone to deny you t hese rights or to as k you
to surrender t he rights. Thes e restrictio ns translate to cer tain respons ibilities for you if you d istribute copi es of
the softwar e, or if you modify it .
For example, if you d istribute copi es of such a program, w hether gratis o r for a fee, you must give th e recipients
all the rights th at you have. You must make sure t hat they, too, receive or c an get the source code . And you
must show them th ese terms so they know t heir rights.
We protect your righ ts with two step s: (1) copyright the soft ware, and (2) offer yo u this license which gi ves you
legal permiss ion to copy, distribut e and/or modify the sof tware.
Also, for each autho r’s protection an d ours, we want to mak e certain that eve ryone under stands that the re
is no warrant y for this free soft ware. If the sof tware is modied by s omeone else and pas sed on, we want its
recipients to k now that what they have is no t the original, so th at any problems intr oduced by others wi ll not
reect on the or iginal author s’ reputations .
Finally, any free pro gram is threaten ed constantly by sof tware patent s. We wish to avoid the dang er that
redistribu tors of a free progr am will individu ally obtain paten t licenses, in effec t making the progr am propriet ary.
To prevent this, we have made i t clear that any paten t must be licensed for ev eryone’s free use or n ot licensed
at all.
The precise ter ms and conditions for copy ing, distribu tion and modica tion follow.
GNU GENERA L PUBLIC LICEN SE
TERMS AND COND ITIONS FOR COPYI NG, DISTRI BUTION AND MOD IFICATION
0. Th is License applies to a ny program or other w ork which contain s a notice placed by the copyr ight holder
saying it may be dist ributed under t he terms of this Gene ral Public Licens e. The “Progra m”, below, refers to
any such program o r work, and a “work b ased on the Progr am” means either th e Program or any der ivative
work under copyr ight law: that is to say, a wor k containing the Pro gram or a portio n of it, either ver batim
or with modicat ions and/or transl ated into another la nguage. (Herei nafter, translati on is included witho ut
limitation in th e term “modicat ion”.) Each licensee is addre ssed as “you”.
Activities ot her than copying, dis tribution an d modication are n ot covered by this Licens e; they are outsid e
its scope. The ac t of running the Pro gram is not restr icted, and the ou tput from the Pro gram is covered
only if its content s constitute a wor k based on the Progr am (independe nt of having been made by r unning
the Program). Whe ther that is true de pends on what the Pr ogram does.
1. You may copy a nd distribute ve rbatim copies of the P rogram’s source cod e as you receive it, in a ny medium,
provided that you con spicuously and app ropriately publ ish on each copy an appro priate copyright n otice
and disclaimer of wa rranty; kee p intact all the not ices that refer to this L icense and to the absen ce of any
warranty ; and give any other rec ipients of the Progr am a copy of this License a long with the Progr am.
You may charge a fee for the physi cal act of transfe rring a copy, and you may at you r option offer war ranty
protection in exc hange for a fee.
2. You may modi fy 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 a nd distribut e such modications o r work under the ter ms of Section 1 above , provided
that you also meet all of t hese conditions:
a) You must ca use the modied les t o carry promin ent notices stati ng that you changed the les and the
date of any change.
b) You must cause any wo rk that you distr ibute or publish, t hat in whole or in par t contains or is der ived
from the Progra m or any part ther eof, to be licensed as a wh ole at no charge to all th ird parties un der
the terms of this Li cense.
c) If th e modied progra m normally reads com mands interac tively when run , you must cause it, w hen
started r unning for such inter active use in the m ost ordinary w ay, to print or display an ann ouncement
including an appr opriate copyrigh t notice and a notice that t here is no warra nty (or else, saying tha t you
provide a warr anty) and that user s may redistrib ute the program un der these conditi ons, and telling
the user how to view a copy of t his License. (Exce ption: if the Progr am itself is inter active but does n ot
normally prin t such an announceme nt, your work based o n the Program is not r equired to print a n
announcement.)
These require ments apply to the mo died work as a whol e. If identiabl e sections of that wor k are
not derived from t he Program, and c an be reasonably co nsidered indepe ndent and separ ate works in
themselves, th en this License, an d its terms, do not a pply to those sectio ns when you distr ibute them as
separate work s. But when you di stribute the sa me sections as par t of a whole which is a wo rk based on the
Program, the d istribution of t he whole must be on th e terms of this Licens e, whose permiss ions for other
licensees exte nd to the entire whol e, and thus to each and ev ery part reg ardless of who wrot e it.