Re: Possible compiler bug with this simple program

["Jeffrey R. Carter" <spam.jrcarter.not@spam.acm.org>]

Jerry wrote:
> 
> In about a hundred cases in this same binding project, I have passed
> an unconstrained array (and its length) as a parameter to an Imported
> C subprogram without consequence--no warnings, no errors, no hangs--on
> several kinds of machines (32-bit and 64-bit). This seems to be
> allowed by ARM B.3.70: "An Ada parameter of an array type with
> component type T, of any mode, is passed as a t* argument to a C
> function, where t is the C type corresponding to the Ada type T."
> There is no restriction on unconstrained array types.

Yes, but you're passing a pointer to an Ada convention-C subprogram to a C 
function, and C is calling that subprogram. The subprogram has a an 
unconstrained array parameter. This says nothing about what happens when C calls 
Ada.

Ada needs to know what the lower bound of this array parameter is, and 
apparently your compiler is getting it wrong. Using a constrained array type 
with a lower bound of zero and an upper bound as large or larger than can occur 
would be the best choice for this situation.

-- 
Jeff Carter
"I fart in your general direction."
Monty Python & the Holy Grail
05