Administrator's Guide

Appendix E. License Conditions
share and change free software--to make sure the software is free for all its users.
This license, the Library General Public License, applies to some specially designated Free
Software Foundation software, and to any other libraries whose authors decide to use it. You
can use it for your libraries, too.
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 know 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 a program with the library, you must provide com-
plete 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.
Our method of protecting your rights has two steps: (1) copyright the library, and (2) of-
fer you this license which gives you legal permission to copy, distribute and/or modify 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.
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 dis-
tinction 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 li-
braries. We concluded that weaker conditions might promote sharing better.
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