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Date: | Mon, 3 Jun 1996 08:17:37 +1000 (EST) |
From: | John Joseph Newbigin <079519 AT bud DOT cc DOT swin DOT edu DOT au> |
To: | "Christoph P. Kukulies" <kuku AT gilberto DOT physik DOT RWTH-Aachen DOT DE> |
Cc: | myskin%inp DOT nsk DOT SU AT psuorvm DOT cc DOT pdx DOT edu, djgpp AT delorie DOT com |
Subject: | Re: What is 'volatile'? |
In-Reply-To: | <199606011042.MAA29398@gilberto.physik.rwth-aachen.de> |
Message-Id: | <Pine.OSF.3.91.960603081454.20552B-100000@bud.cc.swin.edu.au> |
Mime-Version: | 1.0 |
> > Hi all! > > Tell me please what does the keyword 'volatile' or '__volatile__' > > mean. I can't find any info about it in FAQ or docs. > > It's an extension to C (can be found in the gcc docs) and means > that something declared 'volatile' (a function or a variable or > another entity) should not be touched by any compiler optimization > algorithm.. > Sure there's a bit more behind it but this is the most common > reason to declare a piece of code 'volatile'. > The reason I use volatile (I guess it must be the second most common reason:)is to make sure that any variable changed by an interrupt routine is used correctly by the rest of the program. This is needed with and without optimization.
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