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.
38
S
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 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.
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.
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:
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.)
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.
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.
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.
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.