Re: Problem with protected type

[Jeffrey Carter <spam@spam.com>]

Ekkehard Morgenstern wrote:

>  type CoreEvent is limited private;
> 
>  protected BaseEvent is
>   entry Wait;
>   procedure Signal;
>   procedure ManualMode;
>   procedure AutoMode;
>   procedure Reset;
>   function IsSignaled return Boolean;
>  private
>   EventObject : CoreEvent;
>   ManualReset : Boolean := FALSE;
>  end BaseEvent;
> 
> The compiler reports "premature usage of incomplete type derived from
> "BaseEvent"".

That's not a great error message.

I suspect that your real problem is that you omitted the word "type" 
between "protected" and "Baseevent". "protected Baseevent" declares a 
single protected object; "protected type Baseevent" declares a type 
which may then be used to declare many objects of the type.

A type declaration may include a reference to an incomplete type, such 
as Coreevent. An object declaration may not, since it has to allocate 
space for the components, and the compiler does not yet know how much 
space needs to be allocated for Coreevent.

> Can I use a barrier expression that is doing a function call?

Yes, a barrier can be any boolean expression. If you limit yourself to 
the Ravenscar profile, however, a barrier must be a Boolean component of 
the object.

BTW, I find the Ada way, Base_Event, much easier to read than Baseevent, 
which is what my reformatter does with your kind of identifiers.

-- 
Jeff Carter
"Sheriff murdered, crops burned, stores looted,
people stampeded, and cattle raped."
Blazing Saddles
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