Smalltalk - GNU Smalltalk license updated

Author

GNU Smalltalk license updated

Paolo Bonzini

2006-11-24, 8:02 am

As stated in many other occasions in this newsgroup, diifferent parts
of GNU Smalltalk come under two licenses: the virtual machine and the
development environment (compiler and browser) used to come under the
GNU General Public License, while the system class libraries come under
the LGPL.

Starting from version 2.3, which will be released soon, the FSF agreed
to clarify the license in order to widen the range of users of GNU
Smalltalk, and to clarify the cases in which either license applies.
This post explains this change and details the licensing policy of GNU
Smalltalk.

First of all, remember that the GPL is a distribution license.
Anything stated in this post only applies in the case you want to
distribute your software. The GPL will not forbid in any way that you
combine GNU Smalltalk with software that cannot be re-released under
the GPL -- as long as you don't distribute the combination.

The GPL licensing of the virtual machine means that all derivatives of
the virtual machine, must be put under the same license. In other
words, it is strictly forbidden to distribute programs that include the
GNU Smalltalk virtual machine under a license that is incompatible with
the GPL. This also includes any bindings to external libraries. For
example, the bindings to sockets, Gtk+, and so on are released under
the GPL.

In principle, the GPL would not extend to Smalltalk programs, since
these are merely input data for the virtual machine. On the other
hand, using bindings that are under the GPL via dynamic linking would
constitute combining two parts (the Smalltalk program and the bindings)
into one program. Therefore, we added a special exception to the GPL
in order to avoid gray areas that could adversely hit both the project
and its users:

Linking GNU Smalltalk statically or dynamically with other modules is
making a combined work based on GNU Smalltalk. Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

In addition, as a special exception, the Free Software Foundation
give you permission to combine GNU Smalltalk with free software
programs or libraries that are released under the GNU LGPL and with
independent programs running under the GNU Smalltalk virtual machine.

You may copy and distribute such a system following the terms of the
GNU GPL for GNU Smalltalk and the licenses of the other code
concerned, provided that you include the source code of that other
code when and as the GNU GPL requires distribution of source code.

Note that people who make modified versions of GNU Smalltalk are not
obligated to grant this special exception for their modified
versions; it is their choice whether to do so. The GNU General
Public License gives permission to release a modified version without
this exception; this exception also makes it possible to release a
modified version which carries forward this exception.

The same exception is added to the aforementioned bindings. Note that
this change was discussed with Richard Stallman and he agreed that the
introduction of such exception is helpful, both to improve the
usefulness of GNU Smalltalk, and to make the licensing terms clearer.

Regards,

Paolo

Chris Uppal

2006-11-24, 7:02 pm

Paolo Bonzini wrote:

> Starting from version 2.3, which will be released soon, the FSF agreed
> to clarify the license in order to widen the range of users of GNU
> Smalltalk, and to clarify the cases in which either license applies.
> This post explains this change and details the licensing policy of GNU
> Smalltalk.

Good. Thanks.

> Linking GNU Smalltalk statically or dynamically with other modules is
> making a combined work based on GNU Smalltalk. Thus, the terms and
> conditions of the GNU General Public License cover the whole
> combination.
>
> In addition, as a special exception, the Free Software Foundation
> give you permission to combine GNU Smalltalk with free software
> programs or libraries that are released under the GNU LGPL and with
> independent programs running under the GNU Smalltalk virtual machine.

But I don't understand how this works. If I see a bit of GPLed software (from
Some Random Third Party) then the FFS does not, and cannot have (in general),
the right to change the license under which that third party released its
software.

Am I misundertanding the intent of this clarification ? Or maybe the
exception is applicable only to software released /by/ the FSF ?

-- chris

paolo.bonzini@gmail.com

2006-11-24, 7:02 pm

> > In addition, as a special exception, the Free Software Foundation
>
> But I don't understand how this works. If I see a bit of GPLed software (from
> Some Random Third Party) then the FFS does not, and cannot have (in general),
> the right to change the license under which that third party released its
> software.

Right. But suppose you write bindings for library X, which is licensed
under a liberal license (LGPL, or BSD). Since such bindings are
combined with GNU Smalltalk and GNU Smalltalk is GPL, the bindings have
to be GPL. And since the bindings are GPL, and Smalltalk programs
explicitly link to the functions declared by the bindings (they are not
input data as in the interpreter case!), the Smalltalk programs using
them should also have been under the GPL.

The FSF made an exception for the Smalltalk programs in this case: of
course this may apply only if the entire combined work does not include
software that is distributed under:

- either the bare GPL (in this case the Smalltalk program must be GPL)

- or under a GPL-incompatible license (in this case you don't have the
right to distribute the combined work and fulfill the GPL).

The first case happens not only when you use a GPLed class library, but
also for bindings to a GPLed library such as GNU readline. Even if
bindings for GNU readline may be distributed with the exception, it is
useless in this case: the Smalltalk program will still be linking with
GNU readline, and since the latter is released under the GPL, the
Smalltalk program will have to be under the GPL.

> Am I misundertanding the intent of this clarification ? Or maybe the
> exception is applicable only to software released /by/ the FSF ?

No, the FSF is not making any such exception for any software it
releases, except GNU Smalltalk. The above example about GNU readline
should make the matter more clear.

Also, while not strictly necessary from a legal standpoint (this has
been the FSF position on interpreters since forever), the exception
will pacify people that are worried about using GNU Smalltalk as the
underlying virtual machine for proprietary software.

Paolo

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