9
If distribution of object code is made by offering access to copy from a designated place, then offering
e
quivalent 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 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.
