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Re: Limiting a program to a single running instance

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Ken Foskey
October 3, 2007 15:50
Re: Limiting a program to a single running instance
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On Wed, 2007-10-03 at 13:34 -0700, Mark Wagner wrote:
> I've got a Perl program that is run once an hour as a cron job.
> Normally it finishes its task in about ten minutes, but occasionally
> it takes more than an hour to complete.  When this happens, a second
> copy is started, the two copies step on each others' toes, and both
> crash.
> I'm looking for the second copy to know that another copy is running
> and exit after logging a message to that effect.  Any method needs to
> work properly if the first copy crashes rather than exiting cleanly.

Another design for this sort of thing is a mutex.  There are a few
modules for this.  This means you can lock out smaller parts of code and
keep two copies running concurrently doing different work.

Ken Foskey
FOSS developer

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