Subj : Re: Improving read-write lock
To   : comp.programming.threads
From : Joe Seigh
Date : Fri Feb 25 2005 07:22 am

On Fri, 25 Feb 2005 17:47:12 +1000, David Holmes <dholmes@--remove-this-part-dltech.com.au> wrote:


> But it is not a simple story. Once things are broken the response to be
> being broken depends very much on the severity of the problem brokenness
> might cause. If the exception propogates and locks are not released then
> recovery may be impossible without locks that support ownership-stealing. I
> like to think that releasing the lock at least allows for the possibility of
> recovery - but really how do you recover from an unexpected exception. In
> most cases, most programs just give up and die, or give up and hang.
>

You can add a new state to the lock to indicate "damage".  You could
add a return code or a new exception to indicate such.  That might
make pthread cancelation and cleanup a bit interesting if damaged
mutexes were used.  Alternatively, you could have a cleanup thread
waiting to do the cleanup.  I see no reason another thread can't
do cleanup on data that's shared in the first place.  Assuming
cleanup is possible.

-- 
Joe Seigh

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