copying2.txt

操纵DBASEIII文件的程序

GNU LIBRARY GENERAL PUBLIC LICENSE

Version 2, June 1991 

Copyright (C) 1991 Free Software Foundation, Inc.
675 Mass Ave, Cambridge, MA 02139, USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.

[This is the first released version of the library GPL.  It is
 numbered 2 because it goes with version 2 of the ordinary GPL.]

Preamble

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 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, 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 or 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 anyone to deny you
these rights or to ask you to surrender the 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 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. 

Our method of protecting your rights has two steps: (1) copyright the library, and (2)
offer 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
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. 

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, while
the latter only works together with the library. 

Note that it is possible for a library to be covered by the ordinary General Public
License rather than by this special one. 

TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

0. This License Agreement applies to any software library which contains a notice
placed by the copyright holder or other authorized party saying it may be distributed
under the terms of this Library General Public License (also called "this License").
Each licensee is addressed as "you". 

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 "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".) 

"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. 

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. 

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. 

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: 

     a) The modified work must itself be a software library. 

     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. 

     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.) 

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. 

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. 

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. 

This option is useful when you wish to copy part of the code of the Library into a
program that is not a library. 

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. 

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. 

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. 

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. 

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