71
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.