Re: Ptr Problem Question

[Jeffrey Carter <spam@spam.com>]

Arthur Schwarz wrote:

> Each Ptr assignment below yields the following error message:
> 
> --    9.    Ptr     : a.X_Ptr  := Object'Access;
> --       >>> non-local pointer cannot point to local object

A.X_Ptr is declared at the library level. This means that you could 
assign Ptr to a variable declared at the library level, and it would 
exist after the subprogram returns, leaving a dangling reference. Ada's 
accessibility rules prevent this.

If you're sure this won't happen, you can use 'Unchecked_Access instead. 
You are then responsible for making sure you don't leave any dangling 
refererences; the compiler can't help you.

A better question, though, is why you are using pointers. Unless you're 
building a dynamic data structure, pointers are rarely needed in Ada.

-- 
Jeff Carter
"You cheesy lot of second-hand electric donkey-bottom biters."
Monty Python & the Holy Grail
14