mutex m;
condition_variable not_empty;
condition_variable not_full;

void producer()
{
	while(true)
	{
		produce something, store in foo

		unique_lock<mutex> lock(m);
		while (buffer.full())
			not_full.wait(lock);

		buffer.push(foo);

		lock.unlock();
		not_empty.notify_all();
	}
}

void consumer()
{
	while(true)
	{
		unique_lock<mutex> lock(m);
		while (buffer.empty())
			not_empty.wait(lock);

		foo = buffer.top();
		buffer.pop();

		lock.unlock();
		not_full.notify_all();

		use foo
	}
}