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Subject: Re: I don't know what the compiler wants to tell me
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Date: Fri, 04 Nov 2005 05:12:12 GMT
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Date: 2005-11-04T05:12:12+00:00
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Thomas Ruschival wrote:

> hello2b.adb:48:18: left hand of assignment must not be limited

What it means is that assignment (":=") is not defined for limited types. Task 
types are limited types.

>       while Irq = False  -- infinite loop until an external task does 

This (Irq = False) generally indicates a lack of understanding of Booleans. 
Better is

while not Irq loop

That uses negative logic. Positive logic is easier to understand than negative, so

loop
    exit when Irq;

is better still. However, best is to eliminate Irq altogether and have

loop
    ...
    select
       accept Interrupt;

       exit;
    or
    ...
end loop;

Often, naming loops can make them easier to read and understand:

Wait_For_Interrupt : loop
    ...
    exit Wait_For_Interrupt;
    ...
end loop Wait_For_Interrupt;

> 	  Controlled : PrinterTask; -- task To be controlled

Controlled is an object of a task type; an object of a task type is a task.

> 		 Controlled := ToControl;

This is illegal, because Controlled is limited.

-- 
Jeff Carter
"Now go away or I shall taunt you a second time."
Monty Python & the Holy Grail
07