Subj : Re: Improving read-write lock
To   : comp.programming.threads
From : Marcin 'Qrczak' Kowalczyk
Date : Wed Feb 16 2005 06:21 pm

"Joe Seigh" <jseigh_01@xemaps.com> writes:

>> It's not a perfect situation of course, because only one ReadPromotable
>> lock exists.
>
> More than one promotable read lock can exist.  It just has to stay blocked
> until any pior promotable read locks have completed their write access.

No, because if two threads holding promotable read locks try to
promote them, they will deadlock.

Unless you meant a different semantics where promotion may allow other
writers to invervene. I think .NET provides something like this (with
a semi-reliable check whether some writer did actually intervene).

-- 
   __("<         Marcin Kowalczyk
   \__/       qrczak@knm.org.pl
    ^^     http://qrnik.knm.org.pl/~qrczak/

.