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Re: Re: Eval/Fork lesson of the day

by lestrrat (Deacon)
on May 15, 2002 at 16:03 UTC ( #166765=note: print w/replies, xml ) Need Help??

in reply to Re: Eval/Fork lesson of the day
in thread Eval/Fork lesson of the day

The basic premise was that I needed to catch all errors from a series of steps, and if there were any errors in the middle, I needed to do whatever to undo the changes:

while(1) { eval { do_this(); do_that(); fork_and_stuff(); and_why_not_do_this_as_well(); }; if( $@ ) { undo_changes(); log( "there was, like, something wrong: $@" ); } }

It just so happened that one of the subs actually forked, and hence the problem. I wasn't trying to eval the fork() per se... ;)

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Re: Re: Re: Eval/Fork lesson of the day
by graff (Chancellor) on May 15, 2002 at 17:28 UTC
    That makes sense, but it does look a bit tricky. So, I assume you would really want to hit the "undo" block if the fork fails; and maybe you would want to make sure the fork call is the last step in the eval block, so that if any of the other steps fail, you could save yourself the trouble of forking before undoing things.

    When the fork "succeeds", then any problems encountered by the child will be asynchronous with respect to this process, right? And that might make it hard to "undo" whatever the child does, I think. (I'm sure there's a way to deal with that, but as I said, fork is not one of my strong suits.)

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