Subject: Licensing SWI-Prolog

From: "Petr Kocmid" <[email-masked]>
Date: Sun, 13 Feb 2000 06:33:30 +0100

Hello Jan,

I am confused about current licensing status of
the swi-prolog. 

Some readme says it may be distributed freely  
for non-commercial use only and referring to
pl\LICENCE, but I see no such file anywhere. 
However, GPL2 licence is included with it,
which of course contradicts the non-comm
only request, but requires open source of
the derivative work instead. Also, having
GPL2 contradicts having separate commercial 
licence too.

Which licensing models are currently valid?

Could you consider the LGPL licence instead of
GPL2? 

Please note, that embedding prolog engine
in C/C++ application using early binding 
is a derivative work in the sense of GPL2 while
embedding the same engine as a shared or dynamic
library is not. With LGPL, that difference makes
no problem and does not conflict with separate
commercial licences too. 

Petr Kocmid
[email-masked]