Re: Gnat For use at Question

[dewar@cs.nyu.edu (Robert Dewar)]

Spasmo asks why GNAT rejects:
"Some_Array : String(1..4000);
for Some_Array use at 16#bbbbb#;"

GNAT rejects this because it is plainly illegal. Address, in accordance
with the implementation ad vice in the Ada 95 RM is a private type in
GNAT, and you obviously can't use an integer literal as the value of 
a private type.

Look up the facilities in System.Storage_Elements to find out how to
do what you want. Rememeber that GNAT implements the restriction that
the address expression must be a prior defined constant, so you cannot
just use To_Address directly, since a call to To_Address is not static.
So you want something like:

	Some_Array_Address : constant Address := To_Address (16#bbbb#);
        Some_Array : String (1 .. 4000);
        for Some_Array'Address use Some_Array_Address;

P.S. since almost certainly what you have in mind is overlaying the
display buffer, it would be much neater to have an Ada variable with
more structure (something like a two dimensional array of records
containing an attribute which is a packed record and a character).