Legal 80
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non-free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P ublic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w idely
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non-free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".)