Re: Ada Address = C pointer ?

[Mark Johnson <Mark_H_Johnson@Raytheon.com>]

"M. A. Alves" wrote:

> [snip]

> I am in fact using Address and Access_To_Address_Conversions(*) because I
> simply did not find out how to do the trick otherwise.  For example, the C
> function is returning an array of unsigned long.  I want to access that
> array without copying it.  How can you do that with Interfaces.C.Strings
> or even Interfaces.C.Pointers ?
>

Reread the implementation advice in B.3....
 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.

Of course, your mileage may vary - but here's a simple test case that I ran using
GNAT on Linux....

a.c...
#include <string.h>
void a ( int * x, int * y) {
  memcpy(y, x, 40);
}
b.adb...
with Text_Io;
procedure B is
  type Xt is array (1..10) of Integer;
  Y : Xt := (others => 1);
  Z : Xt := (others => 0);

  procedure A (X : Xt; Y : Xt);
  pragma Import(C, A, "a");

  begin
  A(Y, Z);
  if (Z(1)=1) then
    Text_Io.Put_Line("Ok");
  else
    Text_Io.Put_Line("Failed");
  end if;
end B;

which after being built runs and prints out "Ok".

Good luck.
  --Mark