[Info-vax] Volatile, was: Re: yet another sys$qiow question

[Johnny Billquist]

On 2015-08-28 01:59, David Froble wrote:
> And I'm still asking, why would anyone do such?  Is there any valid reason?

I think that as a pure polling loop, I would assume/hope that noone 
would do it.

However, think event loop. Your process is stopped, and can be woken up 
by a gazillion different causes. You do not want to create a wait for 
specific event flags, since this can change rather dynamically, and also 
do not scale. ASTs is a very different solution to an event loop, and is 
not really that applicable in this context.

So, your process stops. At some point it is woken up, at which point it 
checks what have happened, and take appropriate actions, and then goes 
back to sleep. Checking the IOSB as a way to check if an I/O have 
completed as a part of that event loop would be rather reasonable.

	Johnny