Re: [boost] [thread] Question about MT API C++0X N2094

From: Roland Schwarz (roland.schwarz_at_[hidden])
Date: 2006-11-01 14:34:41

Peter Dimov wrote:
> Indeed, sorry for not paying attention.  But the only point of locking a
> mutex is to be able to do that from two different threads at the same time. 
> If you know that only one thread is accessing the scoped_lock at a time, you 
> wouldn't need a scoped_lock in the first place.

Could you please provide an example where it is not possible to
solve the problem with scoped_lock only? I simply cannot find
one. Currently this would be the only "killer argument" for my
proposed aggregate/POD type mutex. Therfore I am very interested
in this.

> .... Sometimes you just need to lock the mutex in one place and unlock 
> it in another, and there is no way around it. 

Are you thinking the following kind of scenario?

void foo() {
        scoped_lock lk(mx);
        bar(lk);
}

void bar(scoped_lock& lk)
{
        lk.unlock();
}

Roland