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Re: Problems with Subroutines

by Juerd (Abbot)
on Sep 01, 2011 at 00:12 UTC ( #923551=note: print w/replies, xml ) Need Help??


in reply to Problems with Subroutines

Beginning Perl has a chapter on subroutines; it's chapter 8 and it answers all your questions.

The error you're getting is caused by trying to read from a filehandle that was opened for output only. You can't do that. Although it's possible to open a filehandle that you can both write to and read from, that's an advanced topic and not suited for beginners.

Also, don't write to the file that you're still reading. Strange things will happen. Instead, write to a new file and rename that when you're done and sure that the old file may be removed. This also avoids some race conditions, and incomplete files if the program should crash before it's done writing.

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[erix]: lazyness-driven inventio :)
[erix]: "the dog ate my homework"
[Eily]: looks more like "all my plates are broken and I don't understand why. Also I can't retrieve the broken parts because the elephant in the room is on the way"
[ambrus]: Eily: also webpages aren't displayed on my monitor no matter what I click with the mouse, and there's a blackout right now, could that be a problem?
[robby_dobby]: ambrus: Yes
[hippo]: erix++: "the browser ate my code"
[robby_dobby]: Eily: Now, people are trying to be inventive with crowdsourcing their work, eh? Sure, call on the admins to k-line these sockpuppet accounts!
[robby_dobby]: hippo: I like how you equated your browser to a dog....

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