Re: Y21C Bug

[Mats Weber <matsw@mail.com>]

Robert A Duff wrote:

> Commit on use is indeed very cool.
> 
> Do you know which operating systems support it?

VMS. And I think most major Unices also support it, as well as NT. If
you want to know, compile and run the following program and see what
happens:

--
with Ada.Numerics.Discrete_Random;

procedure Try_Commit_On_Use is

   Size : constant := 100_000_000;  -- Size of memory allocated.
   
   Pages : constant := 1_000;  -- Number of pages to reference.

   type Big is array (1 .. Size) of Character;
   
   type Big_Access is access Big;
   
   subtype Bar is Integer range 1 .. Pages;
   
   package Bar_Random is new Ada.Numerics.Discrete_Random(Bar);
   
   Generator : Bar_Random.Generator;
   
   Z : Big_Access;
   
begin
   Z := new Big;
   loop
      Z(Size / Pages * Bar_Random.Random(Generator)) :=
         Z(Size / Pages * Bar_Random.Random(Generator));
   end loop;
end;