Re: Porting Ada83 to Ada95 compiler/VxWorks

[Tucker Taft <stt@averstar.com>]

"Robert Kershaw, KG4ASZ" wrote:
> 
> I need to port about 12K SLOC of code in Ada83 to Ada95 running under
> VxWorks. Does anyone know of a good resource describing the
> differences from Ada83 to Ada95?

The short answer is that Ada 83 is a subset of Ada 95.
The long answer about compatibility (and it is probably much
more detail than most people need to know) can be found at:

    http://www.adaic.org/docs/compat-guide/compat-guide6-0.txt
 
> Any advice?

Try compiling the code.  The few incompatibilities that exist
are almost always caught at compile-time, and many compilers
even give you a hint as to how to fix the problem.  Here are
the few "significant" incompatibilities:

   1) type Character now has 256 enumeration literals
       (this was actually permitted even before Ada 95 arrived)
   2) library packages must *not* have a body unless the
       body contains the completion for some declaration in the spec,
       or the spec contains a "pragma Elaborate_Body;"  (i.e. there
       is no such thing as an "optional" library package body in Ada 95)
   3) you need to decide in a generic whether a formal private type
       should or should not allow the actual type to be "indefinite."
       If the answer is yes, then you need to add a "(<>)" to the
       formal private type declaration.

In general, the bigger porting problems are usually due to 
code that was originally target-dependent or compiler-dependent.

> 
> Thanks,
> RSK

-- 
-Tucker Taft   stt@averstar.com   http://www.averstar.com/~stt/
Technical Director, Distributed IT Solutions  (www.averstar.com/tools)
AverStar (formerly Intermetrics, Inc.)   Burlington, MA  USA