From:	ao950 AT FreeNet DOT Carleton DOT CA (Paul Derbyshire)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Volatile
Date:	7 Aug 1997 06:34:04 GMT
Organization:	The National Capital FreeNet
Lines:	19
Message-ID:	<5sbq8s$jjd@freenet-news.carleton.ca>
References:	<199708061619 DOT AA241634394 AT typhoon DOT rose DOT hp DOT com>
Reply-To:	ao950 AT FreeNet DOT Carleton DOT CA (Paul Derbyshire)
NNTP-Posting-Host:	freenet3.carleton.ca
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Andrew Crabtree (andrewc AT typhoon DOT rose DOT hp DOT com) writes:
>>   I know it sounds crazy, but what does the 'voltaile' with a
>> variable/function ?
>> 
> For a variable, basically it means that it should exist in memory, and 
> never be cached in a register.  It has two primary uses.  The first is 
> to allow things like binary semaphores and mutex semaphores to work
> between processes and/or interrupt handlers.  The second is to allow
> memory-mapped i/o to work.

And those timer interrupts and so forth...

What the heck is a "semaphore"???
--
    .*.  Where feelings are concerned, answers are rarely simple [GeneDeWeese]
 -()  <  When I go to the theater, I always go straight to the "bag and mix"
    `*'  bulk candy section...because variety is the spice of life... [me]
Paul Derbyshire ao950 AT freenet DOT carleton DOT ca, http://chat.carleton.ca/~pderbysh

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