- 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.
-^L
- 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.
+ Also, for each distributor's protection, we want to make certain
+that everyone understands that there is no warranty for this free
+library. If the library is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original
+version, so that any problems introduced by others will not reflect on
+the original authors' reputations.
+\f
+ Finally, any free program is threatened constantly by software
+patents. We wish to avoid the danger that companies distributing free
+software will individually obtain patent licenses, thus in effect
+transforming the program into proprietary software. To prevent this,
+we have made it clear that any patent must be licensed for everyone's
+free use or not licensed at all.
+
+ Most GNU software, including some libraries, is covered by the ordinary
+GNU General Public License, which was designed for utility programs. This
+license, the GNU Library General Public License, applies to certain
+designated libraries. This license is quite different from the ordinary
+one; be sure to read it in full, and don't assume that anything in it is
+the same as in the ordinary license.
+
+ The reason we have a separate public license for some libraries is that
+they blur the distinction we usually make between modifying or adding to a
+program and simply using it. Linking a program with a library, without
+changing the library, is in some sense simply using the library, and is
+analogous to running a utility program or application program. However, in
+a textual and legal sense, the linked executable is a combined work, a
+derivative of the original library, and the ordinary General Public License
+treats it as such.
+
+ Because of this blurred distinction, using the ordinary General
+Public License for libraries did not effectively promote software
+sharing, because most developers did not use the libraries. We
+concluded that weaker conditions might promote sharing better.
+
+ However, unrestricted linking of non-free programs would deprive the
+users of those programs of all benefit from the free status of the
+libraries themselves. This Library General Public License is intended to
+permit developers of non-free programs to use free libraries, while
+preserving your freedom as a user of such programs to change the free
+libraries that are incorporated in them. (We have not seen how to achieve
+this as regards changes in header files, but we have achieved it as regards
+changes in the actual functions of the Library.) The hope is that this
+will lead to faster development of free libraries.