From: William Kempf (sirwillard_at_[hidden])
Date: 2000-08-10 10:36:37
--- In boost_at_[hidden], "William Kempf" <sirwillard_at_m...> wrote:
> --- In boost_at_[hidden], "Greg Colvin" <gcolvin_at_u...> wrote:
> > From: "William Kempf" <sirwillard_at_m...>
> > > --- In boost_at_[hidden], "Greg Colvin" <gcolvin_at_u...> wrote:
> > > > What is the simplest, safest language construct we know of
for
> managing
> > > > concurrent access to data? I would say the monitor, as
> developed and
> > > > described by Per Hansen and Tony Hoare in the 1970s, and
> implemented in
> > > > many programming languages since then. The classic 1974
paper
> by Hoare
> > > > remains one of the best introductions
> > > > http://www.acm.org/classics/feb96/
> > > > and Hansen's 1993 review is also very useful
> > > >
http://www.acm.org/pubs/citations/proceedings/plan/154766/p1-
> hansen/
I've taken a look at the classic 1974 paper by Hoare, and this paper
has a very good example of why the simplistic monitor you've
described can not be a replacement for conditions. He's got an
example of a read/write lock implemented using his concept of a
monitor. The implementation requires two conditions. I'm not sure
that a monitor deserves first class implementation in a C++ library
given this. The monitor as Hoare describes it may simply be a
programming idiom used with mutexes and conditions. That's
definately something that's up to debate, but I think I've proven to
myself that we can't do with out the primitives mutex and condition
just because we include a monitor.
I tried to look at Hansen's 1993 review, but I'm no longer an ACM
member and so don't have access to it. (I dropped membership after
graduating in '92).
William Kempf