Re: Runtime versions (GPL vs Modified GPL)

[Samuel Tardieu <sam@rfc1149.net>]

>>>>> "anon" == anon  <anon@anon.org> writes:

anon> The "special exception" clause allows the programmer to use GNAT
anon> acadamic or GPL to develope the software under a compatable GPL
anon> license or the LGPL which is still apart of the GPL license
anon> structure.  Or they can develope the software using GNAT and
anon> then use GNAT PRO, Green hil, etc. Ada to compile the release
anon> binary version under another license.

The first quoted sentence makes little sense: while you are developing
the software, you do not need to put any license on your code; you
only need a license when you are *distributing* your program to
others. Any version of GNAT lets you use the compiler for anything you
want as long as you do not distribute the compiled binary (and
circulation of the binary within a company is not considered as
distributing it).

Then, *if* and *when* you want do distribute a compiled version of
your program, you need to choose a license that will apply to this
particular distribution. When it comes to the choice of an Ada
compiler, you have the following alternatives to produce the
distributed executable:

  - GNAT as obtained from the FSF (which is the copyright owner and
    thus decides under what license it is released) contains the
    "special exception". For example, GNAT as found in Debian has been
    obtained through the FSF and Debian chose to retain this "special
    exception"; you can choose any license you want for the
    distribution of your program, including a proprietary one, and you
    do not have to distribute the source if you do not wish to do so.

  - GNAT Pro as distributed by AdaCore also retains this "special
    exception", as the Debian version does. This allows you to choose
    any license you want for your program.

  - GNAT GPL and GNAT Academic as distributed by AdaCore do *not*
    contain the "special exception". This is a choice made by AdaCore,
    as anyone is free to drop this exception at any time when
    redistributing GNAT (and the recipient cannot re-add it unless he
    is the copyright owner). They chose to make these version of GNAT
    and its associated runtime files a GPL only program. In this case,
    and only in this case, you may only distribute your program under
    a GPL compatible license as it has been linked with the GPL-only
    version of the Ada runtime, which also means that you have to
    make the sources available under this license.

  - If you use GNAT obtained from another source than the ones cited
    above, you need to check whether all the distributors up the chain
    (the chain starts at the FSF and ends at you) chose to retain the
    "special exception" or if anyone in the middle chose to drop it.

  - You may use a compiler other than GNAT, in which case you have to
    check the license of this compiler to determine what it allows and
    what it forbids. For example, a compiler license may ask that you
    pay royalties on the programs you sell, while another lets you do
    whatever you want.

 Sam
-- 
Samuel Tardieu -- sam@rfc1149.net -- http://www.rfc1149.net/