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From: Doug Gregor (dgregor_at_[hidden])
Date: 2004-06-29 08:15:07

On Tuesday 29 June 2004 8:00 am, Christopher Currie wrote:
> > The basic usages (covering about 80%) are:
> >
> > scoped_lock l(m); // Block until it locks.
> > scoped_try_lock l(m); // Try (!) to lock. I'll check the result.
> I disagree here, as well. Say I want to program generically...
> template <typename Mutex, typename Lock>
> class worker_class
> {
> Mutex m_;
> public:
> do_work()
> {
> Lock l(m_); // Does this call block?
> // am I guarenteed to be locked here?
> }
> }
> Yes, it's a contrived case,

I don't believe it is a contrived case. Certainly once we have read/write
mutexes we're going to want to tell generic components which kind of lock
they need to use.

> but the point is that all locks should have
> the same behavior in the 1-argument constructor case, and that is to
> block until this lock is obtained. The is the only way the user can use
> the lock in a generic way.

Absolutely. This is *extremely* important to keep in mind when discussing any
kind of concept taxonomy. Refinements of a concept can only add restrictions,
they cannot remove them.


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