| 1 | GNU LIBRARY GENERAL PUBLIC LICENSE | ||
| 2 | Version 2, June 1991 | ||
| 3 | |||
| 4 | Copyright (C) 1991 Free Software Foundation, Inc. | ||
| 5 | 675 Mass Ave, Cambridge, MA 02139, USA | ||
| 6 | Everyone is permitted to copy and distribute verbatim copies | ||
| 7 | of this license document, but changing it is not allowed. | ||
| 8 | |||
| 9 | [This is the first released version of the library GPL. It is | ||
| 10 | numbered 2 because it goes with version 2 of the ordinary GPL.] | ||
| 11 | |||
| 12 | Preamble | ||
| 13 | |||
| 14 | The licenses for most software are designed to take away your | ||
| 15 | freedom to share and change it. By contrast, the GNU General Public | ||
| 16 | Licenses are intended to guarantee your freedom to share and change | ||
| 17 | free software--to make sure the software is free for all its users. | ||
| 18 | |||
| 19 | This license, the Library General Public License, applies to some | ||
| 20 | specially designated Free Software Foundation software, and to any | ||
| 21 | other libraries whose authors decide to use it. You can use it for | ||
| 22 | your libraries, too. | ||
| 23 | |||
| 24 | When we speak of free software, we are referring to freedom, not | ||
| 25 | price. Our General Public Licenses are designed to make sure that you | ||
| 26 | have the freedom to distribute copies of free software (and charge for | ||
| 27 | this service if you wish), that you receive source code or can get it | ||
| 28 | if you want it, that you can change the software or use pieces of it | ||
| 29 | in new free programs; and that you know you can do these things. | ||
| 30 | |||
| 31 | To protect your rights, we need to make restrictions that forbid | ||
| 32 | anyone to deny you these rights or to ask you to surrender the rights. | ||
| 33 | These restrictions translate to certain responsibilities for you if | ||
| 34 | you distribute copies of the library, or if you modify it. | ||
| 35 | |||
| 36 | For example, if you distribute copies of the library, whether gratis | ||
| 37 | or for a fee, you must give the recipients all the rights that we gave | ||
| 38 | you. You must make sure that they, too, receive or can get the source | ||
| 39 | code. If you link a program with the library, you must provide | ||
| 40 | complete object files to the recipients so that they can relink them | ||
| 41 | with the library, after making changes to the library and recompiling | ||
| 42 | it. And you must show them these terms so they know their rights. | ||
| 43 | |||
| 44 | Our method of protecting your rights has two steps: (1) copyright | ||
| 45 | the library, and (2) offer you this license which gives you legal | ||
| 46 | permission to copy, distribute and/or modify the library. | ||
| 47 | |||
| 48 | Also, for each distributor's protection, we want to make certain | ||
| 49 | that everyone understands that there is no warranty for this free | ||
| 50 | library. If the library is modified by someone else and passed on, we | ||
| 51 | want its recipients to know that what they have is not the original | ||
| 52 | version, so that any problems introduced by others will not reflect on | ||
| 53 | the original authors' reputations. | ||
| 54 | |||
| 55 | Finally, any free program is threatened constantly by software | ||
| 56 | patents. We wish to avoid the danger that companies distributing free | ||
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| 59 | we have made it clear that any patent must be licensed for everyone's | ||
| 60 | free use or not licensed at all. | ||
| 61 | |||
| 62 | Most GNU software, including some libraries, is covered by the ordinary | ||
| 63 | GNU General Public License, which was designed for utility programs. This | ||
| 64 | license, the GNU Library General Public License, applies to certain | ||
| 65 | designated libraries. This license is quite different from the ordinary | ||
| 66 | one; be sure to read it in full, and don't assume that anything in it is | ||
| 67 | the same as in the ordinary license. | ||
| 68 | |||
| 69 | The reason we have a separate public license for some libraries is that | ||
| 70 | they blur the distinction we usually make between modifying or adding to a | ||
| 71 | program and simply using it. Linking a program with a library, without | ||
| 72 | changing the library, is in some sense simply using the library, and is | ||
| 73 | analogous to running a utility program or application program. However, in | ||
| 74 | a textual and legal sense, the linked executable is a combined work, a | ||
| 75 | derivative of the original library, and the ordinary General Public License | ||
| 76 | treats it as such. | ||
| 77 | |||
| 78 | Because of this blurred distinction, using the ordinary General | ||
| 79 | Public License for libraries did not effectively promote software | ||
| 80 | sharing, because most developers did not use the libraries. We | ||
| 81 | concluded that weaker conditions might promote sharing better. | ||
| 82 | |||
| 83 | However, unrestricted linking of non-free programs would deprive the | ||
| 84 | users of those programs of all benefit from the free status of the | ||
| 85 | libraries themselves. This Library General Public License is intended to | ||
| 86 | permit developers of non-free programs to use free libraries, while | ||
| 87 | preserving your freedom as a user of such programs to change the free | ||
| 88 | libraries that are incorporated in them. (We have not seen how to achieve | ||
| 89 | this as regards changes in header files, but we have achieved it as regards | ||
| 90 | changes in the actual functions of the Library.) The hope is that this | ||
| 91 | will lead to faster development of free libraries. | ||
| 92 | |||
| 93 | The precise terms and conditions for copying, distribution and | ||
| 94 | modification follow. Pay close attention to the difference between a | ||
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| 96 | former contains code derived from the library, while the latter only | ||
| 97 | works together with the library. | ||
| 98 | |||
| 99 | Note that it is possible for a library to be covered by the ordinary | ||
| 100 | General Public License rather than by this special one. | ||
| 101 | |||
| 102 | GNU LIBRARY GENERAL PUBLIC LICENSE | ||
| 103 | TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION | ||
| 104 | |||
| 105 | 0. This License Agreement applies to any software library which | ||
| 106 | contains a notice placed by the copyright holder or other authorized | ||
| 107 | party saying it may be distributed under the terms of this Library | ||
| 108 | General Public License (also called "this License"). Each licensee is | ||
| 109 | addressed as "you". | ||
| 110 | |||
| 111 | A "library" means a collection of software functions and/or data | ||
| 112 | prepared so as to be conveniently linked with application programs | ||
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| 115 | The "Library", below, refers to any such software library or work | ||
| 116 | which has been distributed under these terms. A "work based on the | ||
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| 136 | |||
| 137 | 1. You may copy and distribute verbatim copies of the Library's | ||
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| 143 | Library. | ||
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| 157 | stating that you changed the files and the date of any change. | ||
| 158 | |||
| 159 | c) You must cause the whole of the work to be licensed at no | ||
| 160 | charge to all third parties under the terms of this License. | ||
| 161 | |||
| 162 | d) If a facility in the modified Library refers to a function or a | ||
| 163 | table of data to be supplied by an application program that uses | ||
| 164 | the facility, other than as an argument passed when the facility | ||
| 165 | is invoked, then you must make a good faith effort to ensure that, | ||
| 166 | in the event an application does not supply such function or | ||
| 167 | table, the facility still operates, and performs whatever part of | ||
| 168 | its purpose remains meaningful. | ||
| 169 | |||
| 170 | (For example, a function in a library to compute square roots has | ||
| 171 | a purpose that is entirely well-defined independent of the | ||
| 172 | application. Therefore, Subsection 2d requires that any | ||
| 173 | application-supplied function or table used by this function must | ||
| 174 | be optional: if the application does not supply it, the square | ||
| 175 | root function must still compute square roots.) | ||
| 176 | |||
| 177 | These requirements apply to the modified work as a whole. If | ||
| 178 | identifiable sections of that work are not derived from the Library, | ||
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| 186 | it. | ||
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| 196 | the scope of this License. | ||
| 197 | |||
| 198 | 3. You may opt to apply the terms of the ordinary GNU General Public | ||
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| 205 | these notices. | ||
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| 214 | 4. You may copy and distribute the Library (or a portion or | ||
| 215 | derivative of it, under Section 2) in object code or executable form | ||
| 216 | under the terms of Sections 1 and 2 above provided that you accompany |