Re: Safe unlocking

From: those who know me have no need of my name (not-a-real-address_at_usa.net)
Date: 11/28/03

  • Next message: Jens.Toerring_at_physik.fu-berlin.de: "Re: Safe unlocking" 
    Date: 28 Nov 2003 12:13:06 GMT

    in comp.unix.misc i read:

    >Suppose my program starts with creating and locking the file as the
    >follows:

    >I think that you'll readily agree that calling SIGNAL(2) for each possible
    >signal number would be rather clumsy.

    i don't agree. please do call signal (or better, sigaction) for each
    signal which you need to handle.

    >Therefore my question: what is the sure-fire way to remove lock file
    >come well, come ill?

    one simplistic way to handle normal sorts of unexpected death is to fork
    after creating the lock file, then let the parent remove it when the child
    (which does all the work) exits.

    but there is no sure-fire way, because there are things that can happen
    which can terminate your process which cannot be caught (e.g., SIGKILL or a
    power glitch), so it's probably better for you to plan to validate the lock
    file in some fashion (then `steal' the lock if the validation fails). 

    -- 
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  • Next message: Jens.Toerring_at_physik.fu-berlin.de: "Re: Safe unlocking"

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