| 1 | GNU LESSER GENERAL PUBLIC LICENSE
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| 2 | Version 2.1, February 1999
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| 3 |
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| 4 | Copyright (C) 1991, 1999 Free Software Foundation, Inc.
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| 5 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 Lesser GPL. It also counts
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| 10 | as the successor of the GNU Library Public License, version 2, hence
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| 11 | the version number 2.1.]
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| 12 |
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| 13 | Preamble
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| 14 |
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| 15 | The licenses for most software are designed to take away your
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| 16 | freedom to share and change it. By contrast, the GNU General Public
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| 17 | Licenses are intended to guarantee your freedom to share and change
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| 18 | free software--to make sure the software is free for all its users.
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| 19 |
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| 20 | This license, the Lesser General Public License, applies to some
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| 21 | specially designated software packages--typically libraries--of the
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| 22 | Free Software Foundation and other authors who decide to use it. You
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| 23 | can use it too, but we suggest you first think carefully about whether
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| 24 | this license or the ordinary General Public License is the better
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| 25 | strategy to use in any particular case, based on the explanations below.
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| 26 |
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| 27 | When we speak of free software, we are referring to freedom of use,
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| 28 | not price. Our General Public Licenses are designed to make sure that
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| 29 | you have the freedom to distribute copies of free software (and charge
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| 30 | for this service if you wish); that you receive source code or can get
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| 31 | it if you want it; that you can change the software and use pieces of
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| 32 | it in new free programs; and that you are informed that you can do
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| 33 | these things.
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| 34 |
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| 35 | To protect your rights, we need to make restrictions that forbid
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| 36 | distributors to deny you these rights or to ask you to surrender these
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| 37 | rights. These restrictions translate to certain responsibilities for
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| 38 | you if you distribute copies of the library or if you modify it.
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| 39 |
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| 40 | For example, if you distribute copies of the library, whether gratis
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| 41 | or for a fee, you must give the recipients all the rights that we gave
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| 42 | you. You must make sure that they, too, receive or can get the source
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| 43 | code. If you link other code with the library, you must provide
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| 44 | complete object files to the recipients, so that they can relink them
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| 45 | with the library after making changes to the library and recompiling
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| 46 | it. And you must show them these terms so they know their rights.
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| 47 |
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| 48 | We protect your rights with a two-step method: (1) we copyright the
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| 49 | library, and (2) we offer you this license, which gives you legal
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| 50 | permission to copy, distribute and/or modify the library.
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| 51 |
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| 52 | To protect each distributor, we want to make it very clear that
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| 53 | there is no warranty for the free library. Also, if the library is
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| 54 | modified by someone else and passed on, the recipients should know
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| 55 | that what they have is not the original version, so that the original
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| 56 | author's reputation will not be affected by problems that might be
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| 57 | introduced by others.
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| 58 | |
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| 59 |
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| 60 | Finally, software patents pose a constant threat to the existence of
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| 61 | any free program. We wish to make sure that a company cannot
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| 62 | effectively restrict the users of a free program by obtaining a
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| 63 | restrictive license from a patent holder. Therefore, we insist that
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| 64 | any patent license obtained for a version of the library must be
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| 65 | consistent with the full freedom of use specified in this license.
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| 66 |
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| 67 | Most GNU software, including some libraries, is covered by the
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| 68 | ordinary GNU General Public License. This license, the GNU Lesser
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| 69 | General Public License, applies to certain designated libraries, and
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| 70 | is quite different from the ordinary General Public License. We use
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| 71 | this license for certain libraries in order to permit linking those
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| 72 | libraries into non-free programs.
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| 73 |
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| 74 | When a program is linked with a library, whether statically or using
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| 75 | a shared library, the combination of the two is legally speaking a
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| 76 | combined work, a derivative of the original library. The ordinary
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| 77 | General Public License therefore permits such linking only if the
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| 78 | entire combination fits its criteria of freedom. The Lesser General
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| 79 | Public License permits more lax criteria for linking other code with
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| 80 | the library.
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| 81 |
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| 82 | We call this license the "Lesser" General Public License because it
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| 83 | does Less to protect the user's freedom than the ordinary General
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| 84 | Public License. It also provides other free software developers Less
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| 85 | of an advantage over competing non-free programs. These disadvantages
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| 86 | are the reason we use the ordinary General Public License for many
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| 87 | libraries. However, the Lesser license provides advantages in certain
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| 88 | special circumstances.
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| 89 |
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| 90 | For example, on rare occasions, there may be a special need to
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| 91 | encourage the widest possible use of a certain library, so that it becomes
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| 92 | a de-facto standard. To achieve this, non-free programs must be
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| 93 | allowed to use the library. A more frequent case is that a free
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| 94 | library does the same job as widely used non-free libraries. In this
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| 95 | case, there is little to gain by limiting the free library to free
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| 96 | software only, so we use the Lesser General Public License.
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| 97 |
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| 98 | In other cases, permission to use a particular library in non-free
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| 99 | programs enables a greater number of people to use a large body of
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| 100 | free software. For example, permission to use the GNU C Library in
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| 101 | non-free programs enables many more people to use the whole GNU
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| 102 | operating system, as well as its variant, the GNU/Linux operating
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| 103 | system.
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| 104 |
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| 105 | Although the Lesser General Public License is Less protective of the
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| 106 | users' freedom, it does ensure that the user of a program that is
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| 107 | linked with the Library has the freedom and the wherewithal to run
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| 108 | that program using a modified version of the Library.
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| 109 |
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| 110 | The precise terms and conditions for copying, distribution and
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| 111 | modification follow. Pay close attention to the difference between a
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| 112 | "work based on the library" and a "work that uses the library". The
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| 113 | former contains code derived from the library, whereas the latter must
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| 114 | be combined with the library in order to run.
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| 115 | |
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| 116 |
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| 117 | GNU LESSER GENERAL PUBLIC LICENSE
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| 118 | TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
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| 119 |
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| 120 | 0. This License Agreement applies to any software library or other
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| 121 | program which contains a notice placed by the copyright holder or
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| 122 | other authorized party saying it may be distributed under the terms of
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| 123 | this Lesser General Public License (also called "this License").
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| 124 | Each licensee is addressed as "you".
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| 125 |
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| 126 | A "library" means a collection of software functions and/or data
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| 127 | prepared so as to be conveniently linked with application programs
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| 128 | (which use some of those functions and data) to form executables.
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| 129 |
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| 130 | The "Library", below, refers to any such software library or work
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| 131 | which has been distributed under these terms. A "work based on the
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| 132 | Library" means either the Library or any derivative work under
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| 133 | copyright law: that is to say, a work containing the Library or a
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| 134 | portion of it, either verbatim or with modifications and/or translated
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| 135 | straightforwardly into another language. (Hereinafter, translation is
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| 136 | included without limitation in the term "modification".)
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| 137 |
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| 138 | "Source code" for a work means the preferred form of the work for
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| 139 | making modifications to it. For a library, complete source code means
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| 140 | all the source code for all modules it contains, plus any associated
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| 141 | interface definition files, plus the scripts used to control compilation
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| 142 | and installation of the library.
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| 143 |
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| 144 | Activities other than copying, distribution and modification are not
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| 145 | covered by this License; they are outside its scope. The act of
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| 146 | running a program using the Library is not restricted, and output from
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| 147 | such a program is covered only if its contents constitute a work based
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| 148 | on the Library (independent of the use of the Library in a tool for
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| 149 | writing it). Whether that is true depends on what the Library does
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| 150 | and what the program that uses the Library does.
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| 151 |
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| 152 | 1. You may copy and distribute verbatim copies of the Library's
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| 153 | complete source code as you receive it, in any medium, provided that
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| 154 | you conspicuously and appropriately publish on each copy an
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| 155 | appropriate copyright notice and disclaimer of warranty; keep intact
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| 156 | all the notices that refer to this License and to the absence of any
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| 157 | warranty; and distribute a copy of this License along with the
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| 158 | Library.
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| 159 |
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| 160 | You may charge a fee for the physical act of transferring a copy,
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| 161 | and you may at your option offer warranty protection in exchange for a
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| 162 | fee.
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| 163 | |
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| 164 |
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| 165 | 2. You may modify your copy or copies of the Library or any portion
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| 166 | of it, thus forming a work based on the Library, and copy and
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| 167 | distribute such modifications or work under the terms of Section 1
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| 168 | above, provided that you also meet all of these conditions:
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| 169 |
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| 170 | a) The modified work must itself be a software library.
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| 171 |
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| 172 | b) You must cause the files modified to carry prominent notices
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| 173 | stating that you changed the files and the date of any change.
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| 174 |
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| 175 | c) You must cause the whole of the work to be licensed at no
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| 176 | charge to all third parties under the terms of this License.
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| 177 |
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| 178 | d) If a facility in the modified Library refers to a function or a
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| 179 | table of data to be supplied by an application program that uses
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| 180 | the facility, other than as an argument passed when the facility
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| 181 | is invoked, then you must make a good faith effort to ensure that,
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| 182 | in the event an application does not supply such function or
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| 183 | table, the facility still operates, and performs whatever part of
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| 184 | its purpose remains meaningful.
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| 185 |
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| 186 | (For example, a function in a library to compute square roots has
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| 187 | a purpose that is entirely well-defined independent of the
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| 188 | application. Therefore, Subsection 2d requires that any
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| 189 | application-supplied function or table used by this function must
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| 190 | be optional: if the application does not supply it, the square
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| 191 | root function must still compute square roots.)
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| 192 |
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| 193 | These requirements apply to the modified work as a whole. If
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| 194 | identifiable sections of that work are not derived from the Library,
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| 195 | and can be reasonably considered independent and separate works in
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| 196 | themselves, then this License, and its terms, do not apply to those
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| 197 | sections when you distribute them as separate works. But when you
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| 198 | distribute the same sections as part of a whole which is a work based
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| 199 | on the Library, the distribution of the whole must be on the terms of
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| 200 | this License, whose permissions for other licensees extend to the
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| 201 | entire whole, and thus to each and every part regardless of who wrote
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| 202 | it.
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| 203 |
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| 204 | Thus, it is not the intent of this section to claim rights or contest
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| 205 | your rights to work written entirely by you; rather, the intent is to
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| 206 | exercise the right to control the distribution of derivative or
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| 207 | collective works based on the Library.
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| 208 |
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| 209 | In addition, mere aggregation of another work not based on the Library
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| 210 | with the Library (or with a work based on the Library) on a volume of
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| 211 | a storage or distribution medium does not bring the other work under
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| 212 | the scope of this License.
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| 213 |
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| 214 | 3. You may opt to apply the terms of the ordinary GNU General Public
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| 215 | License instead of this License to a given copy of the Library. To do
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| 216 | this, you must alter all the notices that refer to this License, so
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| 217 | that they refer to the ordinary GNU General Public License, version 2,
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| 218 | instead of to this License. (If a newer version than version 2 of the
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| 219 | ordinary GNU General Public License has appeared, then you can specify
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| 220 | that version instead if you wish.) Do not make any other change in
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| 221 | these notices.
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| 222 | |
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| 223 |
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| 224 | Once this change is made in a given copy, it is irreversible for
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| 225 | that copy, so the ordinary GNU General Public License applies to all
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| 226 | subsequent copies and derivative works made from that copy.
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| 227 |
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| 228 | This option is useful when you wish to copy part of the code of
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| 229 | the Library into a program that is not a library.
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| 230 |
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| 231 | 4. You may copy and distribute the Library (or a portion or
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| 232 | derivative of it, under Section 2) in object code or executable form
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| 233 | under the terms of Sections 1 and 2 above provided that you accompany
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| 234 | it with the complete corresponding machine-readable source code, which
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| 235 | must be distributed under the terms of Sections 1 and 2 above on a
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| 236 | medium customarily used for software interchange.
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| 237 |
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| 238 | If distribution of object code is made by offering access to copy
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| 239 | from a designated place, then offering equivalent access to copy the
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| 240 | source code from the same place satisfies the requirement to
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| 241 | distribute the source code, even though third parties are not
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| 242 | compelled to copy the source along with the object code.
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| 243 |
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| 244 | 5. A program that contains no derivative of any portion of the
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| 245 | Library, but is designed to work with the Library by being compiled or
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| 246 | linked with it, is called a "work that uses the Library". Such a
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| 247 | work, in isolation, is not a derivative work of the Library, and
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| 248 | therefore falls outside the scope of this License.
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| 249 |
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| 250 | However, linking a "work that uses the Library" with the Library
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| 251 | creates an executable that is a derivative of the Library (because it
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| 252 | contains portions of the Library), rather than a "work that uses the
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| 253 | library". The executable is therefore covered by this License.
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| 254 | Section 6 states terms for distribution of such executables.
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| 255 |
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| 256 | When a "work that uses the Library" uses material from a header file
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| 257 | that is part of the Library, the object code for the work may be a
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| 258 | derivative work of the Library even though the source code is not.
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| 259 | Whether this is true is especially significant if the work can be
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| 260 | linked without the Library, or if the work is itself a library. The
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| 261 | threshold for this to be true is not precisely defined by law.
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| 262 |
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| 263 | If such an object file uses only numerical parameters, data
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| 264 | structure layouts and accessors, and small macros and small inline
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| 265 | functions (ten lines or less in length), then the use of the object
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| 266 | file is unrestricted, regardless of whether it is legally a derivative
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| 267 | work. (Executables containing this object code plus portions of the
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| 268 | Library will still fall under Section 6.)
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| 269 |
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| 270 | Otherwise, if the work is a derivative of the Library, you may
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| 271 | distribute the object code for the work under the terms of Section 6.
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| 272 | Any executables containing that work also fall under Section 6,
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| 273 | whether or not they are linked directly with the Library itself.
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| 274 | |
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| 275 |
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| 276 | 6. As an exception to the Sections above, you may also combine or
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| 277 | link a "work that uses the Library" with the Library to produce a
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| 278 | work containing portions of the Library, and distribute that work
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| 279 | under terms of your choice, provided that the terms permit
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| 280 | modification of the work for the customer's own use and reverse
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| 281 | engineering for debugging such modifications.
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| 282 |
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| 283 | You must give prominent notice with each copy of the work that the
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| 284 | Library is used in it and that the Library and its use are covered by
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| 285 | this License. You must supply a copy of this License. If the work
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| 286 | during execution displays copyright notices, you must include the
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| 287 | copyright notice for the Library among them, as well as a reference
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| 288 | directing the user to the copy of this License. Also, you must do one
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| 289 | of these things:
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| 290 |
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| 291 | a) Accompany the work with the complete corresponding
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| 292 | machine-readable source code for the Library including whatever
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| 293 | changes were used in the work (which must be distributed under
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| 294 | Sections 1 and 2 above); and, if the work is an executable linked
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| 295 | with the Library, with the complete machine-readable "work that
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| 296 | uses the Library", as object code and/or source code, so that the
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| 297 | user can modify the Library and then relink to produce a modified
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| 298 | executable containing the modified Library. (It is understood
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| 299 | that the user who changes the contents of definitions files in the
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| 300 | Library will not necessarily be able to recompile the application
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| 301 | to use the modified definitions.)
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| 302 |
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| 303 | b) Use a suitable shared library mechanism for linking with the
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| 304 | Library. A suitable mechanism is one that (1) uses at run time a
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| 305 | copy of the library already present on the user's computer system,
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| 306 | rather than copying library functions into the executable, and (2)
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| 307 | will operate properly with a modified version of the library, if
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| 308 | the user installs one, as long as the modified version is
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| 309 | interface-compatible with the version that the work was made with.
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| 310 |
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| 311 | c) Accompany the work with a written offer, valid for at
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| 312 | least three years, to give the same user the materials
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| 313 | specified in Subsection 6a, above, for a charge no more
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| 314 | than the cost of performing this distribution.
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| 315 |
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| 316 | d) If distribution of the work is made by offering access to copy
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| 317 | from a designated place, offer equivalent access to copy the above
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| 318 | specified materials from the same place.
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| 319 |
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| 320 | e) Verify that the user has already received a copy of these
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| 321 | materials or that you have already sent this user a copy.
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| 322 |
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