| 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. |
| | 20 | This license, the Lesser General Public License, applies to some |
| | 21 | specially designated software packages--typically libraries--of the |
| | 22 | Free Software Foundation and other authors who decide to use it. You |
| | 23 | can use it too, but we suggest you first think carefully about whether |
| | 24 | this license or the ordinary General Public License is the better |
| | 25 | strategy to use in any particular case, based on the explanations below. |
| | 26 | |
| | 27 | When we speak of free software, we are referring to freedom of use, |
| | 28 | not price. Our General Public Licenses are designed to make sure that |
| | 29 | you have the freedom to distribute copies of free software (and charge |
| | 30 | for this service if you wish); that you receive source code or can get |
| | 31 | it if you want it; that you can change the software and use pieces of |
| | 32 | it in new free programs; and that you are informed that you can do |
| | 33 | these things. |
| 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 |
| 57 | | software will individually obtain patent licenses, thus in effect |
| 58 | | transforming the program into proprietary software. To prevent this, |
| 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. |
| | 52 | To protect each distributor, we want to make it very clear that |
| | 53 | there is no warranty for the free library. Also, if the library is |
| | 54 | modified by someone else and passed on, the recipients should know |
| | 55 | that what they have is not the original version, so that the original |
| | 56 | author's reputation will not be affected by problems that might be |
| | 57 | introduced by others. |
| | 58 | |
| | 59 | Finally, software patents pose a constant threat to the existence of |
| | 60 | any free program. We wish to make sure that a company cannot |
| | 61 | effectively restrict the users of a free program by obtaining a |
| | 62 | restrictive license from a patent holder. Therefore, we insist that |
| | 63 | any patent license obtained for a version of the library must be |
| | 64 | consistent with the full freedom of use specified in this license. |
| | 65 | |
| | 66 | Most GNU software, including some libraries, is covered by the |
| | 67 | ordinary GNU General Public License. This license, the GNU Lesser |
| | 68 | General Public License, applies to certain designated libraries, and |
| | 69 | is quite different from the ordinary General Public License. We use |
| | 70 | this license for certain libraries in order to permit linking those |
| | 71 | libraries into non-free programs. |
| | 72 | |
| | 73 | When a program is linked with a library, whether statically or using |
| | 74 | a shared library, the combination of the two is legally speaking a |
| | 75 | combined work, a derivative of the original library. The ordinary |
| | 76 | General Public License therefore permits such linking only if the |
| | 77 | entire combination fits its criteria of freedom. The Lesser General |
| | 78 | Public License permits more lax criteria for linking other code with |
| | 79 | the library. |
| | 80 | |
| | 81 | We call this license the "Lesser" General Public License because it |
| | 82 | does Less to protect the user's freedom than the ordinary General |
| | 83 | Public License. It also provides other free software developers Less |
| | 84 | of an advantage over competing non-free programs. These disadvantages |
| | 85 | are the reason we use the ordinary General Public License for many |
| | 86 | libraries. However, the Lesser license provides advantages in certain |
| | 87 | special circumstances. |
| | 88 | |
| | 89 | For example, on rare occasions, there may be a special need to |
| | 90 | encourage the widest possible use of a certain library, so that it becomes |
| | 91 | a de-facto standard. To achieve this, non-free programs must be |
| | 92 | allowed to use the library. A more frequent case is that a free |
| | 93 | library does the same job as widely used non-free libraries. In this |
| | 94 | case, there is little to gain by limiting the free library to free |
| | 95 | software only, so we use the Lesser General Public License. |
| | 96 | |
| | 97 | In other cases, permission to use a particular library in non-free |
| | 98 | programs enables a greater number of people to use a large body of |
| | 99 | free software. For example, permission to use the GNU C Library in |
| | 100 | non-free programs enables many more people to use the whole GNU |
| | 101 | operating system, as well as its variant, the GNU/Linux operating |
| | 102 | system. |
| | 103 | |
| | 104 | Although the Lesser General Public License is Less protective of the |
| | 105 | users' freedom, it does ensure that the user of a program that is |
| | 106 | linked with the Library has the freedom and the wherewithal to run |
| | 107 | that program using a modified version of the Library. |
| | 459 | |
| | 460 | How to Apply These Terms to Your New Libraries |
| | 461 | |
| | 462 | If you develop a new library, and you want it to be of the greatest |
| | 463 | possible use to the public, we recommend making it free software that |
| | 464 | everyone can redistribute and change. You can do so by permitting |
| | 465 | redistribution under these terms (or, alternatively, under the terms of the |
| | 466 | ordinary General Public License). |
| | 467 | |
| | 468 | To apply these terms, attach the following notices to the library. It is |
| | 469 | safest to attach them to the start of each source file to most effectively |
| | 470 | convey the exclusion of warranty; and each file should have at least the |
| | 471 | "copyright" line and a pointer to where the full notice is found. |
| | 472 | |
| | 473 | <one line to give the library's name and a brief idea of what it does.> |
| | 474 | Copyright (C) <year> <name of author> |
| | 475 | |
| | 476 | This library is free software; you can redistribute it and/or |
| | 477 | modify it under the terms of the GNU Lesser General Public |
| | 478 | License as published by the Free Software Foundation; either |
| | 479 | version 2.1 of the License, or (at your option) any later version. |
| | 480 | |
| | 481 | This library is distributed in the hope that it will be useful, |
| | 482 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| | 483 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| | 484 | Lesser General Public License for more details. |
| | 485 | |
| | 486 | You should have received a copy of the GNU Lesser General Public |
| | 487 | License along with this library; if not, write to the Free Software |
| | 488 | Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| | 489 | |
| | 490 | Also add information on how to contact you by electronic and paper mail. |
| | 491 | |
| | 492 | You should also get your employer (if you work as a programmer) or your |
| | 493 | school, if any, to sign a "copyright disclaimer" for the library, if |
| | 494 | necessary. Here is a sample; alter the names: |
| | 495 | |
| | 496 | Yoyodyne, Inc., hereby disclaims all copyright interest in the |
| | 497 | library `Frob' (a library for tweaking knobs) written by James Random Hacker. |
| | 498 | |
| | 499 | <signature of Ty Coon>, 1 April 1990 |
| | 500 | Ty Coon, President of Vice |
| | 501 | |
| | 502 | That's all there is to it! |
| | 503 | |
| | 504 | |