Subj : Re: Deadlock Calculator
To   : comp.programming.threads
From : Uenal Mutlu
Date : Sun May 15 2005 05:59 am

"David Schwartz" wrote
> "Uenal Mutlu" wrote
>
> > Here's an example showing the difference when recursive locking is used:
>
> > DATA:
> > ObjectList: a b
> > fRecursiveLocks: 0
> > Objects in T0: b a
> > Objects in T1: b a a b
> > ANALYSIS:
> > SelfDeadlock: object 'a' in T1(ix=2) vs. T1(ix=1)
> > Result: Deadlock!
>
>     Whew. Good thing we saw the deadlock and caught the bug.
>
> > DATA:
> > ObjectList: a b
> > fRecursiveLocks: 1
> > Objects in T0: b a
> > Objects in T1: b a a b
> > ANALYSIS:
> > Result: No deadlock
>
>     Oops, now the bug slips into release and can bite customers.

It has nothing to do with whether release or debug build.
It just shows the effect of a locking method which permits
a thread to lock the same object multiple times without
blocking (ie. deadlocking) itself.
Ie. calling Lock() for an object (here 'a') which is already
locked by the same thread).
Case 1 is a Lock() method without recursive locking capability, case 2 is with.

.