The GNU Lesser General Public License (LGPL) is another license created by the FSF for the purpose of permitting a certain class of programs, generally subroutine libraries, to be licensed under an FSF license but be permitted to link with non-GPL software programs. Subroutine libraries provide various functions to other programs, and because as part of their function they link with such programs, the resulting program plus library could be considered as a legal matter to be a derivative work. Accordingly, if the other program were licensed under a proprietary license and the library under the GPL and the program and library were distributed together under the proprietary license, the GPL would be violated, as the program plus library would be considered a derivative work that would be subject to limitations on copying, distribution, and modification that are inconsistent with the GPL.
 The use of a GPL-licensed program with a proprietary-licensed library (or any other program, whether under a proprietary license or some other non-GPL license) is not a violation of the GPL license. Rather, the GPL license comes into play only when the GPL-licensed software is copied, distributed, or modified none of which is implicated by the simple use of the software. As explained in more detail later, libraries present some unique technical problems for licensing in that their use may result in the "modification," as that term is defined in the GPL, of the program that uses them.
The LGPL provides an alternative license that preserves many of the benefits of the GPL model for such libraries in fact, the Lesser General Public License was in its first incarnation known as the Library General Public License. LGPL-licensed libraries can be linked with non-GPL licensed programs, including proprietary software. However, libraries need not be licensed under the LGPL, and as the following preamble to the license points out, the preferable way to license libraries, at least under some circumstances, is under the GPL.
The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public Licenses are intended to guarantee your freedom to share and change free software to make sure the software is free for all its users.
This license, the Lesser General Public License, applies to some specially designated software packages typically libraries of the Free Software Foundation and other authors who decide to use it. You can use it too, but we suggest you first think carefully about whether this license or the ordinary General Public License is the better strategy to use in any particular case, based on the explanations below.
When we speak of free software, we are referring to freedom of use, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish); that you receive source code or can get it if you want it; that you can change the software and use pieces of it in new free programs; and that you are informed that you can do these things.
To protect your rights, we need to make restrictions that forbid distributors to deny you these rights or to ask you to surrender these rights. These restrictions translate to certain responsibilities for you if you distribute copies of the library or if you modify it.
For example, if you distribute copies of the library, whether gratis or for a fee, you must give the recipients all the rights that we gave you. You must make sure that they, too, receive or can get the source code. If you link other code with the library, you must provide complete object files to the recipients, so that they can relink them with the library after making changes to the library and recompiling it. And you must show them these terms so they know their rights.
We protect your rights with a two-step method: (1) we copyright the library, and (2) we offer you this license, which gives you legal permission to copy, distribute and/or modify the library.
To protect each distributor, we want to make it very clear that there is no warranty for the free library. Also, if the library is modified by someone else and passed on, the recipients should know that what they have is not the original version, so that the original author's reputation will not be affected by problems that might be introduced by others.
Finally, software patents pose a constant threat to the existence of any free program. We wish to make sure that a company cannot effectively restrict the users of a free program by obtaining a restrictive license from a patent holder. Therefore, we insist that any patent license obtained for a version of the library must be consistent with the full freedom of use specified in this license.
Most GNU software, including some libraries, is covered by the ordinary GNU General Public License. This license, the GNU Lesser General Public License, applies to certain designated libraries, and is quite different from the ordinary General Public License. We use this license for certain libraries in order to permit linking those libraries into non-free programs.
When a program is linked with a library, whether statically or using a shared library, the combination of the two is legally speaking a combined work, a derivative of the original library. The ordinary General Public License therefore permits such linking only if the entire combination fits its criteria of freedom. The Lesser General Public License permits more lax criteria for linking other code with the library.
We call this license the "Lesser" General Public License because it does Less to protect the user's freedom than the ordinary General Public License. It also provides other free software developers Less of an advantage over competing non-free programs. These disadvantages are the reason we use the ordinary General Public License for many libraries. However, the Lesser license provides advantages in certain special circumstances.
For example, on rare occasions, there may be a special need to encourage the widest possible use of a certain library, so that it becomes a de-facto standard. To achieve this, non-free programs must be allowed to use the library. A more frequent case is that a free library does the same job as widely used non-free libraries. In this case, there is little to gain by limiting the free library to free software only, so we use the Lesser General Public License.
In other cases, permission to use a particular library in non-free programs enables a greater number of people to use a large body of free software. For example, permission to use the GNU C Library in non-free programs enables many more people to use the whole GNU operating system, as well as its variant, the GNU/Linux operating system.
Although the Lesser General Public License is Less protective of the users' freedom, it does ensure that the user of a program that is linked with the Library has the freedom and the wherewithal to run that program using a modified version of the Library.
The precise terms and conditions for copying, distribution and modification follow. Pay close attention to the difference between a "work based on the library" and a "work that uses the library". The former contains code derived from the library, whereas the latter must be combined with the library in order to run.
 This version of the LGPL is 2.1, distributed February, 1999. It is copyright © 1991, 1999 by the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. As was the case with the GPL, "Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed."
Much of this preamble parallels the language in the GPL described earlier. There are two new points, however, worth identifying. The first is the decision on the part of the developer as to which license to use for a particular library. The Preamble posits this choice as if it were between the GPL on one hand and the LGPL on the other. To begin with, obviously, developers can choose to license their programs, including their libraries, under any license, FSF-approved or not. For those who are interested in using the GPL-distribution model, however, the Preamble identifies those situations in which LGPL may be favored, such as when the library is intended to replace an already available commercially licensed product.
The second point worthy of mention is the distinction in the LGPL between "work based on the library," which is subject to essentially the same restrictions as imposed by the GPL, and "work that is used with the library," which is not. This distinction is explained in more detail later.
As was the case with the GPL, the first section after the "Terms and Conditions for Copying, Distribution, and Modification" is Section 0, which defines the basic terms used in the license and sets out its fundamental premises.
0. This License Agreement applies to any software library or other program which contains a notice placed by the copyright holder or other authorized party saying it may be distributed under the terms of this Lesser General Public License (also called "this License"). Each licensee is addressed as "you".
The next full paragraph defines small-l "library" as it is used in the LGPL.
A "library" means a collection of software functions and/or data prepared so as to be conveniently linked with application programs (which use some of those functions and data) to form executables.
The next paragraph defines capital-L "Library," a term of art used to refer to the licensed program, and "work based on the Library," another term of art that is equivalent to this book's use of "derivative work."
The "Library", below, refers to any such software library or work which has been distributed under these terms. A "work based on the Library" means either the Library or any derivative work under copyright law: that is to say, a work containing the Library or a portion of it, either verbatim or with modifications and/or translated straightforwardly into another language. (Hereinafter, translation is included without limitation in the term "modification".)
In contrast to the GPL, the LGPL also includes a definition of "source code" in this section; the parallel definition is in Section 3(c) of the GPL.
"Source code" for a work means the preferred form of the work for making modifications to it. For a library, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the library.
This is most likely included here to include a number of files related to the library modules, interfaces, and scripts to maximize the functionality of the source code.
The final paragraph of Section 0 is substantially identical to the paragraph found at the end of the GPL's Section 0.
Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running a program using the Library is not restricted, and output from such a program is covered only if its contents constitute a work based on the Library (independent of the use of the Library in a tool for writing it). Whether that is true depends on what the Library does and what the program that uses the Library does.
Many of the provisions of the LGPL are identical or near-identical to provisions in the GPL. Accordingly, the annotations in the section focus on those provisions in which significant changes have been made. Examine the earlier discussion of the GPL if you have questions about any of the provisions that are not thoroughly discussed here.
Section 1 of the LGPL is substantially identical to Section 1 of the GPL, except that it refers to the "Library" instead of to the Program.
1. You may copy and distribute verbatim copies of the Library's complete source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and distribute a copy of this License along with the Library.
You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.
Section 2 of the LGPL appears to be substantially identical to the equivalent section of the GPL. There are, however, a few noteworthy changes relating to the specific qualities of libraries, including one that sharply limits the LGPL's applicability to programs other than libraries.
2. You may modify your copy or copies of the Library or any portion of it, thus forming a work based on the Library, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions:
This paragraph reads substantially like the first paragraph of the GPL's Section 2, again with the distinction that it uses "Library" in place of "Program."
The first of the clauses of this section, however, imposes a limitation absent from the GPL, i.e., it limits the type of derived work that can come from an LGPL-licensed program.
a) The modified work must itself be a software library.
In Section 0, the LGPL had noted that the license applied to "any software library or other program." This provision, however, limits the ability to create derivative works to those circumstances in which the resulting work is a library, as that term is defined in the LGPL. This may complicate, or, more likely, entirely prevent the creation of derivative works from programs that are licensed under the LGPL but are not software libraries. If the LGPL were to permit such derivative works to be made from programs other than software libraries, Section 2(a) should have read something like "The modified work must itself be a software library if the Library [i.e., the original work] is itself a library." Note that the definition of big-L Library under the LGPL includes both small-l libraries and "work" that has been distributed under the license. This bar on the creation of derivative works other than libraries from LGPL-licensed works makes the LGPL essentially useless as a license for such works. Creators of such works should look to the GPL or another open source license.
Sections 2(b) and 2(c) mirror equivalent provisions in the GPL.
b) You must cause the files modified to carry prominent notices stating that you changed the files and the date of any change.
c) You must cause the whole of the work to be licensed at no charge to all third parties under the terms of this License.
Section 2(d) adds specific limitations on licensed libraries' use of tables or other functionality provided by the program with which the library is intended to function.
d) If a facility in the modified Library refers to a function or a table of data to be supplied by an application program that uses the facility, other than as an argument passed when the facility is invoked, then you must make a good faith effort to ensure that, in the event an application does not supply such function or table, the facility still operates, and performs whatever part of its purpose remains meaningful.
(For example, a function in a library to compute square roots has a purpose that is entirely well-defined independent of the application. Therefore, Subsection 2d requires that any application-supplied function or table used by this function must be optional: if the application does not supply it, the square root function must still compute square roots.)
This maximizes the utility (and the value to other open source and free software developers) of the library by encouraging them to be as portable as possible. The closer a given library comes to standing alone, the easier it is to conform it to function with an application other than the one for which it was originally written.
The last three paragraphs of Section 2 are substantially identical to the parallel provisions in the GPL.
These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Library, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Library, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.
Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Library.
In addition, mere aggregation of another work not based on the Library with the Library (or with a work based on the Library) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.
Section 3 of the LGPL addresses a change in licensing from the LGPL to the GPL.
3. You may opt to apply the terms of the ordinary GNU General Public License instead of this License to a given copy of the Library. To do this, you must alter all the notices that refer to this License, so that they refer to the ordinary GNU General Public License, version 2, instead of to this License. (If a newer version than version 2 of the ordinary GNU General Public License has appeared, then you can specify that version instead if you wish.) Do not make any other change in these notices.
This part of the section apparently addresses the bar inherent in the LGPL or creating derivative works that are not libraries from an LGPL-licensed work. This provision is interesting in that it permits any licensee to "upgrade" the license to the GPL license. It operates as a savings clause, in that it would provide an escape in the event that any interpretation of the LGPL or the GPL prevented a program licensed under one from being used with a program licensed under the other.
This change in the license applicable to a given copy of a library is a one-way street. Once a program is re-licensed as a GPL program, it cannot go back to licensing under the LGPL.
Once this change is made in a given copy, it is irreversible for that copy, so the ordinary GNU General Public License applies to all subsequent copies and derivative works made from that copy.
Of course, as other copies of the library would still be available licensed under the LGPL, this sentence really addresses derivative works.
This option is useful when you wish to copy part of the code of the Library into a program that is not a library.
This sentence is slightly misleading. Re-licensing a program under the GPL is not just "useful" but necessary if the derivative work is not a library, as explained above.
Section 4 substantially parallels similar provisions of the GPL with regard to providing the source code with the binary code.
4. You may copy and distribute the Library (or a portion or derivative of it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange.
As is apparent from the following provisions of the LGPL, the distribution of source code of a library standing alone is more restricted under the LGPL than under the GPL: when the executable or binary code is distributed standing alone, it must be accompanied by the source code.
If distribution of object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place satisfies the requirement to distribute the source code, even though third parties are not compelled to copy the source along with the object code.
The LGPL, like the GPL, does permit the distribution of the source code by offering it on equivalent terms as the executable, such as on an FTP site, if the binary code is so offered.
Section 5 provides the critical definition of the "work that uses the Library." The LGPL was designed to permit open source code to function with code licensed under other models. This section serves that purpose by excluding from the terms of the license "work that uses the Library."
5. A program that contains no derivative of any portion of the Library, but is designed to work with the Library by being compiled or linked with it, is called a "work that uses the Library". Such a work, in isolation, is not a derivative work of the Library, and therefore falls outside the scope of this License.
"[I]n isolation" is the critical phrase of this paragraph, as the rest of the section makes clear.
However, linking a "work that uses the Library" with the Library creates an executable that is a derivative of the Library (because it contains portions of the Library), rather than a "work that uses the library". The executable is therefore covered by this License. Section 6 states terms for distribution of such executables.
 This reference to small-l library should probably be to capital-L Library.
While the "work that uses the Library" remains free to be licensed as the creator wishes, when that work is linked with the Library, the resulting work is considered to be a derivative work (as defined by copyright law) and the LGPL imposes specific terms applicable to the distribution of that program plus library provided in Section 6. This compromise allows creators of "works that use the Library" to retain control over their own works, while imposing some limitation when those works are distributed together with the LGPL-licensed Library.
When a "work that uses the Library" uses material from a header file that is part of the Library, the object code for the work may be a derivative work of the Library even though the source code is not. Whether this is true is especially significant if the work can be linked without the Library, or if the work is itself a library. The threshold for this to be true is not precisely defined by law.
If such an object file uses only numerical parameters, data structure layouts and accessors, and small macros and small inline functions (ten lines or less in length), then the use of the object file is unrestricted, regardless of whether it is legally a derivative work. (Executables containing this object code plus portions of the Library will still fall under Section 6.)
Otherwise, if the work is a derivative of the Library, you may distribute the object code for the work under the terms of Section 6. Any executables containing that work also fall under Section 6, whether or not they are linked directly with the Library itself.
These paragraphs of the LGPL attempt, among other things, to distinguish between different uses of a given Library what is a "work based on the Library" and what is a "work that uses the Library." These paragraphs attempt to draw a distinction that may be impossible to make, except on a case-by-case basis. The LGPL, however, seems to make three distinctions. First, if the putative "work that uses the Library" includes a header file that is part of the Library, it may well be a "work based on the Library" (and therefore be covered by LGPL), particularly if that work can be linked without the Library or if that work is itself a library. Second, if the putative "work that uses the Library" draws only to a limited extent on the Library, measured by reliance only on the specified categories of functionality i.e., only "numerical parameters, data structure layouts and accessors, and small macros and small inline functions (ten lines or less in length)" then it is deemed a "work that uses the Library" (which falls outside the scope of the LGPL), even if it is otherwise a derivative work, as that term is used in copyright law. While the executable file incorporating the Library must be distributed under Section 6, the "work that uses the Library" itself may be licensed free of any limitation. Third, in a sentence probably included as a savings clause if a work is a "derivative work" of the Library, in the sense that it incorporates any code from the Library (as opposed to the object code "in isolation" described in the first paragraph of this section), it is subject to the distribution requirements of Section 6.
These distinctions are unclear and the impact of this section on creators of potential "work that uses the Library" may be hard to predict. Some interpretations of the LGPL distinguish between the dynamic (compiled together with the underlying program) and the static (not so compiled) linking of programs with libraries. Such distinctions are beyond the scope of this book. However, at least at the time of this writing, FSF-licensed libraries may not be dynamically linked, while libraries affiliated with Linus Torvalds and the Linux project may be. Because of the complexity of such problems, users facing these questions should contact the licensor of the Library in question.
So far, we have seen that the LGPL makes distinctions between essentially three different types of work:
The LGPL-licensed Library.
The "work that uses the Library."
The combined "work that uses the Library" and Library together, which I will refer to here as the "combined work," a term not used in the LGPL.
Putting to one side the problem of linking and the extent to which a "work that uses the Library" and the Library are truly distinct programs, the requirements of the LGPL are fairly clear. The "work that uses the Library," when distributed as a "standalone" may be licensed and distributed however the creator wishes, whether under the GPL, the BSD, a proprietary, or any other license. The "Library" must be distributed under the LGPL: the source code must be available under the same terms as the binary code and licensees of the Library must be given the same rights (and be bound by the same restrictions) as the licensor of the Library. Section 2 of the LGPL also states that when a "combined work" is distributed, it is also subject to distribution under the terms of the LGPL. These terms are spelled out in Section 6.
6. As an exception to the Sections above, you may also combine or link a "work that uses the Library" with the Library to produce a work containing portions of the Library, and distribute that work under terms of your choice, provided that the terms permit modification of the work for the customer's own use and reverse engineering for debugging such modifications.
This provision is on its face somewhat unclear. Does this mean that by distributing a combined work, the distributor must distribute the source code for or authorize modifications to the "work that uses the Library"? As is made clear by the following paragraphs, Section 6 requires no such thing.
You must give prominent notice with each copy of the work that the Library is used in it and that the Library and its use are covered by this License. You must supply a copy of this License. If the work during execution displays copyright notices, you must include the copyright notice for the Library among them, as well as a reference directing the user to the copy of this License. Also, you must do one of these things:
After this paragraph follows provisions similar in purpose to those in Section 3 of the GPL. They are designed to give notice of the application of copyright to the Library and the fact that the Library is licensed under the LGPL. They also give licensees access to the source code of the Library and allow them to make modifications to it.
a) Accompany the work with the complete corresponding machine-readable source code for the Library including whatever changes were used in the work (which must be distributed under Sections 1 and 2 above); and, if the work is an executable linked with the Library, with the complete machine-readable "work that uses the Library", as object code and/or source code, so that the user can modify the Library and then relink to produce a modified executable containing the modified Library. (It is understood that the user who changes the contents of definitions files in the Library will not necessarily be able to recompile the application to use the modified definitions.)
Accordingly, the distributor must distribute the source code to the Library (including any modifications made by the distributor), and the binary code of the "work that uses a Library" provided in such a way so that licensees can modify the Library and relink it to the "work that uses the Library."
b) Use a suitable shared library mechanism for linking with the Library. A suitable mechanism is one that (1) uses at run time a copy of the library already present on the user's computer system, rather than copying library functions into the executable, and (2) will operate properly with a modified version of the library, if the user installs one, as long as the modified version is interface-compatible with the version that the work was made with.
This provision describes another option for distributing the combined work that may be more user-friendly.
The following provisions are substantially identical to those in Section 3 of the GPL:
c) Accompany the work with a written offer, valid for at least three years, to give the same user the materials specified in Subsection 6a, above, for a charge no more than the cost of performing this distribution.
d) If distribution of the work is made by offering access to copy from a designated place, offer equivalent access to copy the above specified materials from the same place.
e) Verify that the user has already received a copy of these materials or that you have already sent this user a copy.
Section 6(e) of the LPGL offers an option unique to the LGPL, which may be useful when the distibutor is distributing a modified version of the "work that uses the Library" to users who have already received the Library used as part of the combined work.
The form of the executable of the "work that uses the Library" is defined in the following paragraph of Section 6.
For an executable, the required form of the "work that uses the Library" must include any data and utility programs needed for reproducing the executable from it. However, as a special exception, the materials to be distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable.
Accordingly, to distribute the combined work in compliance with Section 6, the distributor must include data and utility programs (and any other components) that are necessary to allow the combined work to function as originally intended with the Library, unless those components are already included with the operating system upon which the combined program is intended to run. If the combined work relies on libraries (or other programs) that are intrinsic either to the "work that uses the Library" or the Library itself (or to the operating system), the combined work cannot be distributed without violating the LGPL. This is made explicit in the following paragraph.
It may happen that this requirement contradicts the license restrictions of other proprietary libraries that do not normally accompany the operating system. Such a contradiction means you cannot use both them and the Library together in an executable that you distribute.
It may be that a distributor would like to distribute a work that consists of the "work that uses the Library" (which the distributor has the power to distribute), the Library, and another program, such as another library, which the distributor does not have the authority to distribute, but that users already own or may be able to purchase. Such a distribution is not permitted under the LGPL. If the distributor cannot distribute all the components of the combined work, the distributor cannot distribute any part of it. End users, of course, are free to combine the combined work with libraries (or other programs) that they may otherwise have access to, as such combinations are outside the scope of the LGPL. However, they may not copy, distribute, or modify such works.
Section 7 addresses the situation in which a distributor has created a work based on the Library and has placed it side by side with another library under a proprietary license (or license other than the LGPL that permits the distributor to distribute it) to make it into what is in effect a single library. The distributor may do so without nullifying any license provisions applicable to the other library, subject to certain conditions.
7. You may place library facilities that are a work based on the Library side-by-side in a single library together with other library facilities not covered by this License, and distribute such a combined library, provided that the separate distribution of the work based on the Library and of the other library facilities is otherwise permitted, and provided that you do these two things:
a) Accompany the combined library with a copy of the same work based on the Library, uncombined with any other library facilities. This must be distributed under the terms of the Sections above.
b) Give prominent notice with the combined library of the fact that part of it is a work based on the Library, and explaining where to find the accompanying uncombined form of the same work.
The standalone executable form of the Library must be distributed along with the combined library, subject to the terms otherwise applicable under the LGPL (i.e., with the source code accompanying the Library) and prominent notice must be given as to where the uncombined form of the Library may be found (and presumably accompanied by its source code). This is somewhat confusing because the uncombined form of the work based on the Library must be part of the package. Presumably, identifying the filename would be sufficient.
Section 8 of the LGPL operates much like Section 4 of the GPL.
8. You may not copy, modify, sublicense, link with, or distribute the Library except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense, link with, or distribute the Library is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.
Section 9 of the LGPL likewise corresponds to Section 5 of the GPL.
9. You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Library or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Library (or any work based on the Library), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Library or works based on it.
The remaining sections of the LGPL, 10 through 16, are substantially identical to Sections 6 through 12 of the GPL. They are included here for completeness.
10. Each time you redistribute the Library (or any work based on the Library), the recipient automatically receives a license from the original licensor to copy, distribute, link with or modify the Library subject to these terms and conditions. You may not impose any further restrictions on the recipients' exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties with this License.
11. If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Library at all. For example, if a patent license would not permit royalty-free redistribution of the Library by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Library.
If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply, and the section as a whole is intended to apply in other circumstances.
It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice.
This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.
12. If the distribution and/or use of the Library is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Library under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License.
13. The Free Software Foundation may publish revised and/or new versions of the Lesser General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.
Each version is given a distinguishing version number. If the Library specifies a version number of this License which applies to it and "any later version", you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Library does not specify a license version number, you may choose any version ever published by the Free Software Foundation.
14. If you wish to incorporate parts of the Library into other free programs whose distribution conditions are incompatible with these, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally.
15. BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE LIBRARY "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE LIBRARY IS WITH YOU. SHOULD THE LIBRARY PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
16. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE LIBRARY AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE LIBRARY (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
END OF TERMS AND CONDITIONS
Following the end of the LGPL's terms and conditions are instructions on how to implement the LGPL. Again, these mirror the instructions in the GPL.
How to Apply These Terms to Your New Libraries
If you develop a new library, and you want it to be of the greatest possible use to the public, we recommend making it free software that everyone can redistribute and change. You can do so by permitting redistribution under these terms (or, alternatively, under the terms of the ordinary General Public License).
To apply these terms, attach the following notices to the library. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found.
one line to give the library's name and an idea of what it does.Copyright (C) year name of author
This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Also add information on how to contact you by electronic and paper mail.
You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the library, if necessary. Here is a sample; alter the names:
Yoyodyne, Inc., hereby disclaims all copyright interest in the library `Frob' (a library for tweaking knobs) written by James Random Hacker.
signature of Ty Coon, 1 April 1990Ty Coon, President of Vice
That's all there is to it!