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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: A question about task's select delay alternative
Date: Mon, 23 Apr 2018 20:06:26 +0200
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On 04/23/2018 07:32 PM, NiGHTS wrote:
> 
> What does "delay" actually do to the CPU? In this case I am using the Adacore GNAT compiler for a PC. Is it a loop constantly evaluating elapsed time? Or is it some kind of timed interrupt?

What timed selective accept "does to the CPU" is not defined by the language. 
It's determined by the compiler implementation and, probably, by the features of 
the OS, if any. So there's no Ada answer to your question.

I don't know how GNAT implements this, but my experience with it is that blocked 
tasks don't use significant CPU. You can test this easily enough.

Why do you care?

-- 
Jeff Carter
"When danger reared its ugly head, he bravely
turned his tail and fled."
Monty Python and the Holy Grail
60