145
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. These restrictio ns translate to cer tain responsibilities for you if you distribute copies of
the library, or if y ou modify it.
For example, if you d istribute copi es of the library, wh ether gratis or for a fe e, you must give the r ecipients all
the rights that we g ave you. You must make sure th at they, too, receive or can g et the source code. If yo u link
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them with the lib rary, after mak ing changes to the lib rary and recomp iling it. And you mus t show them these
terms so they know t heir rights.
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Also, for each dist ributor’s prote ction, we want to make ce rtain that eve ryone unders tands that ther e is no
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to know that what they have is not the original version, so that any problems introduced by others will not
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Finally, any free prog ram is threaten ed constantly by sof tware paten ts. We wish to avoid the dan ger that
companies distr ibuting free sof tware will in dividually obta in patent licenses , thus in effect tr ansforming the
program into pr oprietary s oftware. To preven t this, we have made it cle ar that any patent mus t be licensed for
everyone’s free u se or not licensed at all .
Most GNU soft ware, including s ome libraries , is covered by the ordina ry GNU Gener al Public License, w hich
was designed for u tility progra ms. This license, th e GNU Library G eneral Public L icense, applies to cer tain
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assume that any thing in it is the same a s in the ordinar y license.
The reason we have a se parate public lice nse for some librar ies is that they blur th e distinction we us ually
make between mod ifying or adding to a pr ogram and simply u sing it. Linkin g a program with a li brary, withou t
changing the libr ary, is in some sense si mply using the libr ary, and is analogous t o running a utilit y program
or application pr ogram. However, in a tex tual and legal sen se, the linked execu table is a combined wor k, a
derivative of th e original libra ry, and the ordinar y General Publ ic License treats i t as such.
Because of this blu rred distinc tion, using the ord inary Gener al Public License for lib raries did not ef fectively
promote softw are sharing, be cause most develop ers did not use the lib raries. We conclud ed that weaker
conditions might promote sharing better.
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from the free st atus of the librar ies themselves. T his Library G eneral Public Li cense is intended to pe rmit
developers of non-free programs to use free libraries, while preserving your freedom as a user of such
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difference bet ween a “work base d on the library ” and a “work that uses t he library”. Th e former contains
code derived fro m the library, whi le the latter only wo rks together wi th the librar y.
Note that it is possib le for a library to be cov ered by the ordinar y General Publ ic License rather t han by this
special one.
GNU LIBRA RY GENERAL PUB LIC LICENSE
TERMS AND CONDI TIONS FOR COPYIN G, DISTRIB UTION AND MODIF ICATION
0. This Licen se Agreement appl ies to any softwar e library which co ntains a notice placed by t he copyright
holder or other au thorized part y saying it may be dist ributed under t he terms of this Libr ary Genera l
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