Re: Ada and OpenMP

[Shark8 <onewingedshark@gmail.com>]

On Thursday, March 7, 2013 8:42:15 PM UTC-7, Randy Brukardt wrote:
> 
> In order for that to be the case, the pragma would have to make various 
> constructs illegal in the loop and in the surrounding code (exception 
> handlers, any code where one iteration of the loop depends on the next, 
> erroneous use of shared variables). But a pragma shouldn't be changing the 
> legality rules of the language. (And it's not clear this would really fix 
> the problem.)

Why would that have to change the semantics of the program: since there would have to be a non-implementation-defined code-generation method (for when the pragma was off) the compiler should just use that if those constructs are used.

It limits the usefulness, yes; but there's no reason to assume that it should cause erroneous execution. -- I suppose that in early versions of playing w/ an experimental version there might be some because of some case that was overlooked.  -- Though this does seem to bring us back to the idea of exceptions (and how to indicate/assert to the compiler that none, or a limited set, can be raised).

> 
> 
> 
> Alternatively, the parallel version could simply be erroneous if any of 
> 
> those things happened. But that means you have no idea what will happen, and 
> 
> you've introduced new forms of erroneousness (meaning that there is no 
> 
> chance that the pragma would ever be standardized).
> 
> 
> 
> Ada is about doing things right, and that should be true even for 
> 
> implementation-defined stuff. And we *need* people to figure out good ways 
> 
> of doing these things (for instance, a "parallel" classification for 
> 
> functions would be very helpful). The sloppy way helps little.
> 
> 
> 
>                                        Randy "No New Pragmas" Brukardt