Re: Licensing Questions

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Sat, 20 Oct 2012 19:18:18 +0200, aditya siram <aditya.siram@gmail.com>  
a écrit:

> Hi all,
> Having looked at the Alioth benchmarks I'm looking into Ada as an  
> alternative to C++ but I'm totally confused by the licensing.
Good choice!

Ludovic Brenta will give you better replies than I, but here we go…

> It seems like there's two entities GNU and ADACore both offering the a  
> compiler/runtime but with different restrictions so please excuse these  
> simple questions:
> - How are the two products different? Are they just the same codebase  
> with different support models?
Same code base, but different support models, indeed.

   * FSF GNAT comes with no support, and a delay of about
     one year lagging behind GNAT Pro/GNAT GPL ;
   * GNAT GPL comes with no support, but benefits from more
     reactive updates than FSF GNAT, while still lagging behind GNAT Pro ;
   * GNAT Pro comes with full support and a very reactive team of long
     time experienced professional Ada developpers.

> - Can I develop commercial closed-source libraries and software using  
> the GNU version of GNAT?

   * With FSF GNAT which comes with the runtime library exception: yes (*)
   * With GNAT GPL: no
   * With GNAT Pro: yes (**)

(*) Beware that some some other conditions may make your applications  
covered by the GPL.
(**) It will even give you the right to use the otherwise GPL additional  
libraries, for any purpose you want, either commercial, open, closed  
source.

> - Will there be compatibility issues between GNU GNAT and Adacore GNAT  
> beyond missing Ada 2012 features?

FSF GNAT is lagging, but that's a matter of delay and patience. GNAT GPL  
is more up to date. GNAT Pro is a lot more up to date than the two  
formers. There are compatibility issues with AUnit (AUnit is to Ada, what  
JUnit is to Java), and both are incompatible.


> - Is AdaCore the only company working on GNAT right now?
As far as I know, yes, except there are people working on GNAT FSF too.

> - Are there performance differences between the two compilers?

No. Except if you need support for no‑runtime variant or any other kind of  
specific runtime meeting specific requirement, then you will need GNAT  
Pro. Otherwise, both provides comparable performances.


-- 
“Syntactic sugar causes cancer of the semi-colons.” [1]
“Structured Programming supports the law of the excluded muddle.” [1]
[1]: Epigrams on Programming — Alan J. — P. Yale University