Re: [boost] More Threads Review

From: Peter Dimov (pdimov_at_[hidden])
Date: 2002-10-18 10:18:33

Of historical interest: from my review of the Threads library, 31.08.2001:

"The mutex is missing one bit of functionality that I consider critical.
When
two threads need to lock two (or more) mutexes, the lock order must be the
same to avoid deadlocks. No support is provided for this operation. Possible
alternatives are

template<class M1, class M2, ...> class scoped_multiple_lock
{
    scoped_multiple_lock(M1 &, M2 &, ...);
};

or

template<class M1, class M2, ...> class mutex_tuple
{
    typedef ... scoped_lock;
    mutex_tuple(M1 &, M2 &, ...);
};"

"I'd like to see

template<class M, class P, class F> void wait(M & m, P p, F f)
{
    typename M::scoped_lock lock(m);
    while(!p()) this->wait(lock);
    f();
}

added, for people that want to go the extra mile (when someone bothers to
define a predicate to use the wait(l, p) form, (s)he would probably define
an action object, too.)"