Re: Threads: Atomic Counter

From: William Kempf (sirwillard_at_[hidden])
Date: 2000-08-31 16:43:33

--- In boost_at_[hidden], "Bill Wade" <bill.wade_at_s...> wrote:
> > From: William Kempf [mailto:sirwillard_at_m...]
> 
> > You aren't suggesting that exchange is not useful, however,
> > are you?  It's really the only portable way to read/write an 
atomic_t
> > value.  (I'm not distinguishing exchange() from get()/set() 
because
> > they are equivalent functionality with different interface
> > signatures.)

[snip]

Very good explanation.  (And I guess this means we can assume that 
all platforms must support basic atomic read/write... I didn't think 
that one through.)  I learned something here.  You are quite right 
that on Win32 it makes no sense what so ever to use InerlockedExhange 
as a get().  Interesting that every book/article/etc. I've read 
suggests doing this, but that's another issue all together (you often 
can't trust such books ;).

However, I still think we're just splitting hairs.  Even though it 
may result in an extra lock, exchange() can be used to perform 
get/set.  For performance reasons, yes, I can see adding get/set to 
my list, but I don't think we're talking about removing anything 
here.  Or are we?

Bill Kempf