[Boost-users] Re: boost::read_write_mutex simple usage question.

From: Michael Glassford (glassfordm_at_[hidden])
Date: 2005-03-09 07:32:00

Gordon Smith wrote:
> The following code seems to deadlock on the second (read) scoped lock (not
> what I would expect):
> 
> boost::read_write_mutex
> mutex(boost::read_write_scheduling_policy::alternating_single_read);
> {
> 
> boost::read_write_mutex::scoped_write_lock writeLock(mutex);
> 
> }
> 
> {
> 
> boost::read_write_mutex::scoped_read_lock readLock(mutex);
> 
> }

There are some definite problems with read_write_mutex in the 1.31 
release and this is one of them. Unfortunately the unit tests were quite 
lacking and didn't catch a bug as simple as this.

I have a fixed read_write_mutex that I'm nearly ready to check in. I'm 
not happy with it--the code is too complex and the mutex object is too 
big, but at least it's a lot more correct, I hope. I have also expanded 
the unit tests. Probably too much, in fact: they check a lot more, but 
there is some duplication and they take quite a long time to run.

Mike