Posted by Andy Hassall on 07/21/07 14:40

On Fri, 20 Jul 2007 01:14:02 +0200, Martin Larsen
<martin+spamfree+larsen@bigfoot.com> wrote:

>When a PHP program links to a library using include or require (or their
>_once variations), is the library then linked dynamically or statically?
>
>While it might seem irrelevant from a technical point of view, the
>linking method is important when it comes to licencing issues as some
>licences, like GPL, differ between those kinds of linking when it comes
>to viewing the library as a derivative work of the main program.
>
>Therefore it is quite important to know what kind of linking is in
>effect when including libraries, and I hope someone in this group can
>shed some light on this matter.

Have you seen the following - not sure if it helps, or muddies the waters
further:

http://www.gnu.org/licenses/gpl-faq.html#IfInterpreterIsGPL

In particular the final two paragraphs:

"Another similar and very common case is to provide libraries with the
interpreter which are themselves interpreted. For instance, Perl comes with
many Perl modules, and a Java implementation comes with many Java classes.
These libraries and the programs that call them are always dynamically linked
together.

A consequence is that if you choose to use GPL'd Perl modules or Java classes
in your program, you must release the program in a GPL-compatible way,
regardless of the license used in the Perl or Java interpreter that the
combined Perl or Java program will run on. "


The implication appears to be that loading Perl modules is treated as "dynamic
linking" for the purposes of the license (pure technical definitions aside).
Perl modules are often "pure-Perl" and so very closely match "require/include"
for PHP libraries.

--
Andy Hassall :: andy@andyh.co.uk :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool

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