[Python-ideas] Monitor implementation for the stdlib?

Adam Olsen rhamph at gmail.com
Mon Oct 22 18:22:00 CEST 2007


On 10/22/07, George Sakkis <george.sakkis at gmail.com> wrote:
> On 10/22/07, Adam Olsen <rhamph at gmail.com> wrote:
>
> > A method is often *NOT* the
> > correct granularity to achieve a thread-safe API!  Consider:
> >
> > l = ... some "thread-safe" list ...
> > if l:
> >     x = l.pop()
> >
> > There's two method calls, so you cannot guarantee the object hasn't
> > changed between them.  I get the impression this is regarded as a
> > major mistake in Java's extensive use of monitors - plastering locks
> > everywhere just isn't good enough.
>
> My Java's kinda rusty but IIRC one can use synchronized blocks on an
> object to achieve finer granularity.

You need coarser granularity to achieve correctness in this case.

-- 
Adam Olsen, aka Rhamphoryncus



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