Re: requeue with abort and timed call

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Sun, 4 Jan 2009 10:03:44 -0800 (PST), ishikawa@arielworks.com wrote:

> On Jan 4, 6:09�am, "Jeffrey R. Carter"
> <spam.jrcarter....@spam.acm.org> wrote:

>> Delay statements and calls to Ada.Text_IO.Put_Line are potentially blocking
>> operations. It is an error to call potentially blocking operations from a
>> protected action. See ARM 9.5.1.

> I'm sorry, I overlooked it.

No, it is perfectly legal to use Put_Line in protected actions *with* GNAT.

GNAT implementation explicitly permits this use. So Jeffrey's comment was
irrelevant here.

You should report this bug to AdaCore.

> How about this one;
> 
> with Ada.Text_IO; use Ada.Text_IO;
> procedure Timed_Protected is
>    Z : boolean := True;

Pedantically, you should have added pragma Atomic (Z), because you access
it from different tasks. And probably Volatile (Z) to prevent loop
optimization.

But much simpler would be a primitive busy waiting:

entry E1 when True is
   T : Time := Clock + 5.0;
begin
   for I in Unsigned_64'Range loop
      exit when Clock >= T;
   end loop;
end E1;

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de