Reading between the lines a little, especially in some of you later replies, it looks to me like you are using a cluster of machines to do some heavy duty image processing and that the individual machines are fighting over claiming images to process. If that is the case then a better solution may be to consider one of the job scheduling modules such as Schedule::Load (disclaimer: I've not used the module, but the docs imply it does the right stuff).

If you want to roll your own task management a common technique to manage scheduling and locking is to use a database which provides transacted processing to mediate locking and task queue management.

For a build and automated test system I've put together I use a mysql database. The system processes about 10,000 tasks a month across a build/test farm comprising 6 machines using a mixture of Linux, Mac and Windows boxes. The locking can be done, but it is tricky and needs care to get right!

True laziness is hard work

In reply to Re: randomising file order returned by File::Find by GrandFather
in thread randomising file order returned by File::Find by jefferis

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