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From: Paul Chardon <paul.chardon@avions.aerospatiale.fr>
Subject: Re: Two-Way Task Communication In Ada (w/o Protected Objects)
Date: 1996/11/27
Message-ID: <329BE98B.446B9B3D@avions.aerospatiale.fr>#1/1
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references: <19961125215900.QAA23391@ladder01.news.aol.com>
to: ericferg@aol.com
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Date: 1996-11-27T00:00:00+00:00
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ericferg@aol.com wrote:
> 
> In a message dated 96-11-24 20:15:03 EST, blaak@mda.ca writes:
> 
> << Two way communication with peers can be done by using a protected
> object. Just
>  pretty it up with Send/Receive operations (make a Channel abstraction)
> and have
>  the tasks work with a channel object to communicate.
>   >>
> 
> Thanks for the info.  Though I didn't mention it, I was actually trying to
> AVOID  intermediate protected objects between the tasks (which would act
> as shared "dequeues" or "argument buffers" ... the "Channel abstraction"
> you mention).
> 
> Would anyone happen to know of any way to position or structure Ada task
> declarations such that two tasks will have visibility of each other, and
> may _directly_ invoke each other's entries (and thus provide for direct,
> two way message & argument passing, without the use of intermediate
> argument buffers)?
> 
> If so, please post a reply or e-mail me at EricFerg@aol.com
> 
> Thanks once again, blaak@mda.ca, for your response!
> 
> Eric Ferguson

A way to do that is offer by the structure of specification and body.
You can then build such compilations units :
-----------------------
Task A is
	entry entry_A;
end A;
-----------------------
Task B is
	entry entry_B;
end B;
-----------------------
with A;
Task body B is
begin
	...
	A.entry_A;
end B;
-----------------------
with B;
Task body A is
begin
	...
	B.entry_B;
end A;	
-----------------------

I hope it is what you mean. If not, I've buid a data structure in Ada95
with a tagged type and a task in order to make visibility possible
between two objects without to use the dependency between body and spec.

	Bye, Paul.