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Re^3: File Locking plus delete Lockfile question

by gone2015 (Deacon)
on Feb 12, 2009 at 16:02 UTC ( [id://743374] : note . print w/replies, xml ) Need Help??


in reply to Re^2: File Locking plus delete Lockfile question
in thread File Locking plus delete Lockfile question

Having a single lock for many independent counts seems like a shame.

Suppose when you "deleted" the count file you first wrote -1 to it. Then any processes that have it open, will later read -1, and can drop the file and loop round to open/create the new instance.

Should you care, Winders doesn't appear to let you unlink a file you have open.

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Re^4: File Locking plus delete Lockfile question
by rovf (Priest) on Feb 13, 2009 at 10:09 UTC
    Having a single lock for many independent counts seems like a shame.

    Indeed it is, as I would unnecessarily block an application which could otherwise run; and I agree that it would not be strictly necessary. In this special case however, it turns out not to be such a problem: The typical running time of one instance is about half an hour, the time spent in a critical region is usually a couple of seconds, sometimes half a minute, and the task to be performed is so that on a fragile Windows machine, I'm not so unhappy to know that with the present implementations, no two tasks are going to do the same in parallel, even though in theory they can't disturb each other.

    Winders doesn't appear to let you unlink a file you have open.
    Thank you, good to know.

    -- 
    Ronald Fischer <ynnor@mm.st>