| 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 | 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 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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