| 1 | GNU LIBRARY GENERAL PUBLIC LICENSE
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| 2 | Version 2, June 1991
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| 3 |
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| 4 | Copyright (C) 1991 Free Software Foundation, Inc.
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| 5 | 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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| 6 | Everyone is permitted to copy and distribute verbatim copies
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| 7 | of this license document, but changing it is not allowed.
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| 8 |
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| 9 | [This is the first released version of the library GPL. It is
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| 10 | numbered 2 because it goes with version 2 of the ordinary GPL.]
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| 11 |
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| 12 | Preamble
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| 13 |
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| 14 | The licenses for most software are designed to take away your
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| 15 | freedom to share and change it. By contrast, the GNU General Public
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| 16 | Licenses are intended to guarantee your freedom to share and change
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| 17 | free software--to make sure the software is free for all its users.
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| 18 |
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| 19 | This license, the Library General Public License, applies to some
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| 20 | specially designated Free Software Foundation software, and to any
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| 21 | other libraries whose authors decide to use it. You can use it for
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| 22 | your libraries, too.
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| 23 |
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| 24 | When we speak of free software, we are referring to freedom, not
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| 25 | price. Our General Public Licenses are designed to make sure that you
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| 26 | have the freedom to distribute copies of free software (and charge for
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| 27 | this service if you wish), that you receive source code or can get it
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| 28 | if you want it, that you can change the software or use pieces of it
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| 29 | in new free programs; and that you know you can do these things.
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| 30 |
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| 31 | To protect your rights, we need to make restrictions that forbid
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| 32 | anyone to deny you these rights or to ask you to surrender the rights.
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| 33 | These restrictions translate to certain responsibilities for you if
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| 34 | you distribute copies of the library, or if you modify it.
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| 35 |
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| 36 | For example, if you distribute copies of the library, whether gratis
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| 37 | or for a fee, you must give the recipients all the rights that we gave
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| 38 | you. You must make sure that they, too, receive or can get the source
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| 39 | code. If you link a program with the library, you must provide
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| 40 | complete object files to the recipients so that they can relink them
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| 41 | with the library, after making changes to the library and recompiling
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| 42 | it. And you must show them these terms so they know their rights.
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| 43 |
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| 44 | Our method of protecting your rights has two steps: (1) copyright
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| 45 | the library, and (2) offer you this license which gives you legal
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| 46 | permission to copy, distribute and/or modify the library.
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| 47 |
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| 48 | Also, for each distributor's protection, we want to make certain
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| 49 | that everyone understands that there is no warranty for this free
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| 50 | library. If the library is modified by someone else and passed on, we
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| 51 | want its recipients to know that what they have is not the original
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| 52 | version, so that any problems introduced by others will not reflect on
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| 53 | the original authors' reputations.
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| 54 | |
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| 55 |
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| 56 | Finally, any free program is threatened constantly by software
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| 57 | patents. We wish to avoid the danger that companies distributing free
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| 58 | software will individually obtain patent licenses, thus in effect
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| 59 | transforming the program into proprietary software. To prevent this,
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| 60 | we have made it clear that any patent must be licensed for everyone's
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| 61 | free use or not licensed at all.
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| 62 |
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| 63 | Most GNU software, including some libraries, is covered by the ordinary
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| 64 | GNU General Public License, which was designed for utility programs. This
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| 65 | license, the GNU Library General Public License, applies to certain
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| 66 | designated libraries. This license is quite different from the ordinary
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| 67 | one; be sure to read it in full, and don't assume that anything in it is
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| 68 | the same as in the ordinary license.
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| 69 |
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| 70 | The reason we have a separate public license for some libraries is that
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| 71 | they blur the distinction we usually make between modifying or adding to a
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| 72 | program and simply using it. Linking a program with a library, without
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| 73 | changing the library, is in some sense simply using the library, and is
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| 74 | analogous to running a utility program or application program. However, in
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| 75 | a textual and legal sense, the linked executable is a combined work, a
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| 76 | derivative of the original library, and the ordinary General Public License
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| 77 | treats it as such.
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| 78 |
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| 79 | Because of this blurred distinction, using the ordinary General
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| 80 | Public License for libraries did not effectively promote software
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| 81 | sharing, because most developers did not use the libraries. We
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| 82 | concluded that weaker conditions might promote sharing better.
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| 83 |
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| 84 | However, unrestricted linking of non-free programs would deprive the
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| 85 | users of those programs of all benefit from the free status of the
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| 86 | libraries themselves. This Library General Public License is intended to
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| 87 | permit developers of non-free programs to use free libraries, while
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| 88 | preserving your freedom as a user of such programs to change the free
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| 89 | libraries that are incorporated in them. (We have not seen how to achieve
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| 90 | this as regards changes in header files, but we have achieved it as regards
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| 91 | changes in the actual functions of the Library.) The hope is that this
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| 92 | will lead to faster development of free libraries.
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| 93 |
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| 94 | The precise terms and conditions for copying, distribution and
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| 95 | modification follow. Pay close attention to the difference between a
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| 96 | "work based on the library" and a "work that uses the library". The
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| 97 | former contains code derived from the library, while the latter only
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| 98 | works together with the library.
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| 99 |
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| 100 | Note that it is possible for a library to be covered by the ordinary
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| 101 | General Public License rather than by this special one.
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| 102 | |
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| 103 |
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| 104 | GNU LIBRARY GENERAL PUBLIC LICENSE
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| 105 | TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
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| 106 |
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| 107 | 0. This License Agreement applies to any software library which
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| 108 | contains a notice placed by the copyright holder or other authorized
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| 109 | party saying it may be distributed under the terms of this Library
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| 110 | General Public License (also called "this License"). Each licensee is
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| 111 | addressed as "you".
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| 112 |
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| 113 | A "library" means a collection of software functions and/or data
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| 114 | prepared so as to be conveniently linked with application programs
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| 115 | (which use some of those functions and data) to form executables.
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| 116 |
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| 117 | The "Library", below, refers to any such software library or work
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| 118 | which has been distributed under these terms. A "work based on the
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| 119 | Library" means either the Library or any derivative work under
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| 120 | copyright law: that is to say, a work containing the Library or a
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| 121 | portion of it, either verbatim or with modifications and/or translated
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| 122 | straightforwardly into another language. (Hereinafter, translation is
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| 123 | included without limitation in the term "modification".)
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| 124 |
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| 125 | "Source code" for a work means the preferred form of the work for
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| 126 | making modifications to it. For a library, complete source code means
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| 127 | all the source code for all modules it contains, plus any associated
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| 128 | interface definition files, plus the scripts used to control compilation
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| 129 | and installation of the library.
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| 130 |
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| 131 | Activities other than copying, distribution and modification are not
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| 132 | covered by this License; they are outside its scope. The act of
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| 133 | running a program using the Library is not restricted, and output from
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| 134 | such a program is covered only if its contents constitute a work based
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| 135 | on the Library (independent of the use of the Library in a tool for
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| 136 | writing it). Whether that is true depends on what the Library does
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| 137 | and what the program that uses the Library does.
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| 138 |
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| 139 | 1. You may copy and distribute verbatim copies of the Library's
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| 140 | complete source code as you receive it, in any medium, provided that
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| 141 | you conspicuously and appropriately publish on each copy an
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| 142 | appropriate copyright notice and disclaimer of warranty; keep intact
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| 143 | all the notices that refer to this License and to the absence of any
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| 144 | warranty; and distribute a copy of this License along with the
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| 145 | Library.
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| 146 |
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| 147 | You may charge a fee for the physical act of transferring a copy,
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| 148 | and you may at your option offer warranty protection in exchange for a
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| 149 | fee.
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| 150 | |
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| 151 |
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| 152 | 2. You may modify your copy or copies of the Library or any portion
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| 153 | of it, thus forming a work based on the Library, and copy and
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| 154 | distribute such modifications or work under the terms of Section 1
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| 155 | above, provided that you also meet all of these conditions:
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| 156 |
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| 157 | a) The modified work must itself be a software library.
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| 158 |
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| 159 | b) You must cause the files modified to carry prominent notices
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| 160 | stating that you changed the files and the date of any change.
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| 161 |
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| 162 | c) You must cause the whole of the work to be licensed at no
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| 163 | charge to all third parties under the terms of this License.
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| 164 |
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| 165 | d) If a facility in the modified Library refers to a function or a
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| 166 | table of data to be supplied by an application program that uses
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| 167 | the facility, other than as an argument passed when the facility
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| 168 | is invoked, then you must make a good faith effort to ensure that,
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| 169 | in the event an application does not supply such function or
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| 170 | table, the facility still operates, and performs whatever part of
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| 171 | its purpose remains meaningful.
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| 172 |
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| 173 | (For example, a function in a library to compute square roots has
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| 174 | a purpose that is entirely well-defined independent of the
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| 175 | application. Therefore, Subsection 2d requires that any
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| 176 | application-supplied function or table used by this function must
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| 177 | be optional: if the application does not supply it, the square
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| 178 | root function must still compute square roots.)
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| 179 |
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| 180 | These requirements apply to the modified work as a whole. If
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| 181 | identifiable sections of that work are not derived from the Library,
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| 182 | and can be reasonably considered independent and separate works in
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| 183 | themselves, then this License, and its terms, do not apply to those
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| 184 | sections when you distribute them as separate works. But when you
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| 185 | distribute the same sections as part of a whole which is a work based
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| 186 | on the Library, the distribution of the whole must be on the terms of
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| 187 | this License, whose permissions for other licensees extend to the
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| 188 | entire whole, and thus to each and every part regardless of who wrote
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| 189 | it.
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| 190 |
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| 191 | Thus, it is not the intent of this section to claim rights or contest
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| 192 | your rights to work written entirely by you; rather, the intent is to
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| 193 | exercise the right to control the distribution of derivative or
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| 194 | collective works based on the Library.
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| 195 |
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| 196 | In addition, mere aggregation of another work not based on the Library
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| 197 | with the Library (or with a work based on the Library) on a volume of
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| 198 | a storage or distribution medium does not bring the other work under
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| 199 | the scope of this License.
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| 200 |
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| 201 | 3. You may opt to apply the terms of the ordinary GNU General Public
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| 202 | License instead of this License to a given copy of the Library. To do
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| 203 | this, you must alter all the notices that refer to this License, so
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| 204 | that they refer to the ordinary GNU General Public License, version 2,
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| 205 | instead of to this License. (If a newer version than version 2 of the
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| 206 | ordinary GNU General Public License has appeared, then you can specify
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| 207 | that version instead if you wish.) Do not make any other change in
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| 208 | these notices.
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| 209 | |
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| 210 |
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| 211 | Once this change is made in a given copy, it is irreversible for
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| 212 | that copy, so the ordinary GNU General Public License applies to all
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| 213 | subsequent copies and derivative works made from that copy.
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| 214 |
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| 215 | This option is useful when you wish to copy part of the code of
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| 216 | the Library into a program that is not a library.
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| 217 |
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| 218 | 4. You may copy and distribute the Library (or a portion or
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| 219 | derivative of it, under Section 2) in object code or executable form
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| 220 | under the terms of Sections 1 and 2 above provided that you accompany
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| 221 | it with the complete corresponding machine-readable source code, which
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| 222 | must be distributed under the terms of Sections 1 and 2 above on a
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| 223 | medium customarily used for software interchange.
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| 224 |
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| 225 | If distribution of object code is made by offering access to copy
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| 226 | from a designated place, then offering equivalent access to copy the
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| 227 | source code from the same place satisfies the requirement to
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| 228 | distribute the source code, even though third parties are not
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| 229 | compelled to copy the source along with the object code.
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| 230 |
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| 231 | 5. A program that contains no derivative of any portion of the
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| 232 | Library, but is designed to work with the Library by being compiled or
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| 233 | linked with it, is called a "work that uses the Library". Such a
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| 234 | work, in isolation, is not a derivative work of the Library, and
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| 235 | therefore falls outside the scope of this License.
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| 236 |
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| 237 | However, linking a "work that uses the Library" with the Library
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| 238 | creates an executable that is a derivative of the Library (because it
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| 239 | contains portions of the Library), rather than a "work that uses the
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| 240 | library". The executable is therefore covered by this License.
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| 241 | Section 6 states terms for distribution of such executables.
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| 242 |
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| 243 | When a "work that uses the Library" uses material from a header file
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| 244 | that is part of the Library, the object code for the work may be a
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| 245 | derivative work of the Library even though the source code is not.
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| 246 | Whether this is true is especially significant if the work can be
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| 247 | linked without the Library, or if the work is itself a library. The
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| 248 | threshold for this to be true is not precisely defined by law.
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| 249 |
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| 250 | If such an object file uses only numerical parameters, data
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| 251 | structure layouts and accessors, and small macros and small inline
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| 252 | functions (ten lines or less in length), then the use of the object
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| 253 | file is unrestricted, regardless of whether it is legally a derivative
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| 254 | work. (Executables containing this object code plus portions of the
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| 255 | Library will still fall under Section 6.)
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| 256 |
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| 257 | Otherwise, if the work is a derivative of the Library, you may
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| 258 | distribute the object code for the work under the terms of Section 6.
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| 259 | Any executables containing that work also fall under Section 6,
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| 260 | whether or not they are linked directly with the Library itself.
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| 261 | |
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| 262 |
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| 263 | 6. As an exception to the Sections above, you may also compile or
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| 264 | link a "work that uses the Library" with the Library to produce a
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| 265 | work containing portions of the Library, and distribute that work
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| 266 | under terms of your choice, provided that the terms permit
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| 267 | modification of the work for the customer's own use and reverse
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| 268 | engineering for debugging such modifications.
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| 269 |
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| 270 | You must give prominent notice with each copy of the work that the
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| 271 | Library is used in it and that the Library and its use are covered by
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| 272 | this License. You must supply a copy of this License. If the work
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| 273 | during execution displays copyright notices, you must include the
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| 274 | copyright notice for the Library among them, as well as a reference
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| 275 | directing the user to the copy of this License. Also, you must do one
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| 276 | of these things:
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| 277 |
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| 278 | a) Accompany the work with the complete corresponding
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| 279 | machine-readable source code for the Library including whatever
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| 280 | changes were used in the work (which must be distributed under
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| 281 | Sections 1 and 2 above); and, if the work is an executable linked
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| 282 | with the Library, with the complete machine-readable "work that
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| 283 | uses the Library", as object code and/or source code, so that the
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| 284 | user can modify the Library and then relink to produce a modified
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| 285 | executable containing the modified Library. (It is understood
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| 286 | that the user who changes the contents of definitions files in the
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| 287 | Library will not necessarily be able to recompile the application
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| 288 | to use the modified definitions.)
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| 289 |
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| 290 | b) Accompany the work with a written offer, valid for at
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| 291 | least three years, to give the same user the materials
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| 292 | specified in Subsection 6a, above, for a charge no more
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| 293 | than the cost of performing this distribution.
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| 294 |
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