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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: multiple delay alternative
Date: Tue, 6 Mar 2018 17:36:41 +0100
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Date: 2018-03-06T17:36:41+01:00
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On 03/06/2018 02:50 AM, Mehdi Saada wrote:
> 
> Before that, one thing I can't get, even after asking other people:
> for protected objects, in a protected procedure, when it's blocked, because a reading (protected function) or an entry is being served, are the calls to the procedure put on a queue as with entries ?
> Someone said me the advantage of protected procedures was that you don't have to wait, but I read also they were exclusive with each others... damn.

An entry call may block, because the barrier is False or the task is not 
executing an accept for it. A protected procedure call doesn't block, because it 
has no barrier, but it may have to wait to obtain exclusive access to the PO. 
Blocking and waiting are 2 different concepts.

If you have multiple calls to protected procedures of a PO at the same time, I 
don't see anything that prevents that being implemented with a queue of callers. 
The important thing is that the calls are mutually exclusive and higher priority 
callers have precedence over lower priority ones.

-- 
Jeff Carter
"He that hath no beard is less than a man."
Much Ado About Nothing
132