I believe this to be the case, but I'm unable to find any documentation on how plug-ins integrate with your software. (I am asked to give you my details before being allowed to read the FAQ!) Are they really linked in,
or
could they be counted as separate programs?
The way we use modules is by using include() statements that include the modules in the calling page thus forming a single source page that the PHP interpreter interpretes.
Modules work with objects generated by the main application, they use functions from various project-wide include files. They use database query wrapper functions etc.
Also, you ought to follow the instructions of how to apply the GPL to your software more closely. Most of your files seem not to have any copyright information, for example. Are they covered by the GPL or another "Open Source" licence?
I don't know which files you are looking at, I am talking about the development versions that uses this in (almost) all source files:
/* $Id: banner.php,v 1.9 2001/12/14 12:55:49 hpdl Exp $
osCommerce, Open Source E-Commerce Solutions http://www.oscommerce.com
Copyright (c) 2001 osCommerce
Released under the GNU General Public License */
Is that sufficient?
The third party thinks that their modules (which I believe are based on our sample modules, but they won't show us the sources) can be published under any license they like. They even used our mailing lists to advertise their modules.
Jan Wildeboer