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Re: Bug #189164: libdbd-mysql-perl uses GPL lib, may be used by GPL-incompatible apps

On Tuesday, May 27, 2003, at 23:21 US/Eastern, Steve Langasek wrote:

Not all: the terms of section 3 talk about covered source code in very
broad terms of "all modules [the work] contains".  Can you expand on
your understanding of this phrase?

Section 3 reads, in part:

	You may copy and distribute the Program (or a work based
	on it, under Section 2) in object code or executable form
	under the terms ofSections 1 and 2 above provided that you
	also do one of the following:

	    a) 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; or,

Later, complete source code is defined, in part, as "all the source code for all modules the work contains."

In order to be a part of the complete source code, the source has to be for a module that the Program or a work based on the Program [i.e., a derivative work] contains.

This leads fairly clearly to your asymmetry below:

One possibility that I had not thoroughly considered is that in the case
of an application, "all modules" includes any libraries referenced by
the application; but that in the case of a library, "all modules" does
not include any applications which use that library, because the
*library* which is GPLed does not encode any information pointing to the

I think it might even be possible that symmetry is preserved; that is, dynamic linking a GPL'd work to a non-GPL'd library might be allowed, too, iff that does not form a derivative work. Why? Because if those are two separate works under copyright law, then the non-GPL'd library is not a module of the work.

I'm not sure I like this asymmetry (I'm pretty sure it
isn't the FSF's intention),

I think the FSF argues that a program using the library is a derivative work of the library, in which case the program using the library is a "work based on [the Program]" for GPL 3.

However, depending on how Lotus v. Borland is interpreted, this reasoning may be specious.

Noted. I've come to believe that the basis for claiming the application
is a derived work in these cases is very weak, but it still seems
prudent to treat dynamically-linked works as covered by the GPL's source
code requirements for the time being.

As Debian doesn't have a legal war chest (and doesn't want a bunch of bad press, either), it's quite prudent. Then again, it'd end all our OpenSSL problems real quick ;-D

However, I think for some cases --- such as the mess that started this whole thread, and for other things that have been discussed, like command-line utilities in shell scripts, we should go ahead and "link" 'em.

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