Subj : Re: Memory Barriers, Compiler Optimizations, etc.
To   : comp.programming.threads
From : Alexander Terekhov
Date : Mon Feb 07 2005 11:17 am


"Neill Clift [MSFT]" wrote:
> 
> "Alexander Terekhov" <terekhov@web.de> wrote in message
> news:420506AC.4D92C384@web.de...
> >
> > Same basis as with respect to preservation of sequence of std IO
> > calls to dev/null (with destination known in advance so to speak).
> > The thing is that C/C++ volatile abuse isn't really "observable
> > behavior" under single-threaded C/C++ standard(s), you know.
> >
> 
> In section 6.5.3 of the ANSI C standard as a footnote it says:
> 
> 'A volatile declaration may be used to describe an object
> corresponding to a memory-mapped input/output port...'

Yes. Note that I said "volatile abuse". Simply put, when you write 
something like

volatile int i = 1;

int main() {
  return --i;  
}

you better be prepared that smart compiler can tranform it to

int main() {
}

regards,
alexander.

.