🚀 go-pugleaf

Webb Scales (scales@zko.dec.com) wrote:
: David Brownell wrote:
: > One of the really nice techniques is to have a "Locker" class to grab mutexes
: > as needed, and then release it automatically on all exits.  [...]
: > That kind of class really helps get rid of the bugs you have due
: > to locks not getting released uniformly on all codepaths.
: 
: For instance, if a thread holding a mutex via the "Locker" class terminates
: prematurely (due to an exception or cancellation), then the mutex will be
: unlocked automagically, despite the fact that whatever it was supposed to
: protect is now likely to be in an inconsistent state.  

Good point.  In my use of Lockers, I always pass a pointer to the surrounding
(monitor) object so that the Locker can find and acquire the local lock, e.g.,

     Locker exclusion(this);

Thus, the Locker's destructor can assert the monitor's invariants or
check them and attempt to tidy up.  What I'd really like is a way for
my destructor to know that it is being called through the processing
of an exception and to have access to that exception object.

Tom Payne (thp@cs.ucr.edu)