Re: New copying license for classes/modules: CGPL

[dewar@merv.cs.nyu.edu (Robert Dewar)]

Woulter says

<<The GPL/LGPL licenses are not adequate for classes as these must be
compiled into a program, but they are really used in the same way as a
library: to get access to already coded functions. Similarly for non-OO
programming, small utilies can easier be compiled into a program (and
possible altered a bit) than linked with a shared lib (you must make
sure the target system has the lib you use etc). An example would be GIF
decoders and time/date functions.

I therefore suggest a CGPL license which says:
- using the classes (or subroutines, modules, ...) for any product is
allowed, commercial, GPL, LGPL, BSD, etc.

- Any enhancements to the classes must be released freely with source by
uploading to a server like sunsite.unc.edu (this is stronger than the
GPL/LGPL requirement)

- additional classes made in a program using them, need not be released.

There are some other cases where the CGPL should also be used, like
wrappers for libraries. These need to be compiled into a program
although it's clear they are used like a library, but the code must be
compiled into the program. This latter requirement means the LGPL
doesn't work (it becomes automatically equivalent to a GPL).>>


Robert replies

One thing that people seem confused on is that GPL is simply a form of license
used by some people because it suits their purposes. If you are writing a
piece of code, you are the author and copyright holder (assuming no prior
agreements to the contrary), and you can decide how to license it. You can
use the GPL if it suits your purpose, but if it doesn't, you can modify it
in any manner you like. So if you are writing something where you wish to
use a modified version of the GPL, you can go ahead and do it. It is helpful
if you make clear what your modifications are, so that people are not confused.

As to the class issue itself, in Ada of course, the equivalent problem does
not exist, since Ada works with semantic connection using WITH, rather than
by copying text.

However, with Ada, the issue of generics does arise, not because text is
copied, but because the code is copied into your program, and for GNAT we
use a specially modified version of the GPL for the library that makes
clear that generics do not cause a problem:

-- As a special exception,  if other files  instantiate  generics from this --
-- unit, or you link  this unit with other files  to produce an executable, --
-- this  unit  does not  by itself cause  the resulting  executable  to  be --
-- covered  by the  GNU  General  Public  License.  This exception does not --
-- however invalidate  any other reasons why  the executable file  might be --
-- covered by the  GNU Public License.                                      --

So if you have some software that you want to release under your "CGPL",
just go ahead, no debate is required, no agreement from anyone else is
required, and probably the most useful way to advance the discussion is
to release the sotware, and then let users point out any problems.