Re: On GET_LOCK ()

[Paul DuBois]

At 8:48 AM -0500 7/28/99, <sinisa@stripped> wrote:
>Benjamin Pflugmann writes:
> > Hi.
> >
> > > What do you think that I suggest to Monty that we add a NON_WAIT
> > > option to the get_lock, which would not hang, but would return 0 if a
> > > lock is struck. In that case, a programmer could check the return code
> > > and inform the user that a resource is unavailable .....
> >
> > Either I totally misunderstand you or you are talking about
> > GET_LOCK('foo',0), which is already available and will return 0 in
> > case of an existing lock...?
> >
> > Bye,
> >
> >         Benjamin.
> >
>
>Yes, you are partially right.
>
>'0' is returned when lock has passed it's timeout, which in case of
>'0' means always.

Are you saying the GET_LOCK() call will fail to obtain the lock i
you specify a timeout value of 0?  That isn't so.  If the lock is
available, GET_LOCK() will succeed.  If not, GET_LOCK() will return
0.  In both cases it returns immediately.  It seems to me this is
a perfectly adequate way of "polling" for a lock.

>
>No, there should be then some other value, like '2' or '-1' for non
>wait locks

I think I need to see an example of where this is needed.  I'm not
sure I understand why GET_LOCK(name,0) doesn't do what's required.

--
Paul DuBois, paul@stripped