Beefy Boxes and Bandwidth Generously Provided by pair Networks
Think about Loose Coupling

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.

Comment on Re: Problems with Subroutines

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://923551]
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others chanting in the Monastery: (6)
As of 2015-11-29 17:16 GMT
Find Nodes?
    Voting Booth?

    What would be the most significant thing to happen if a rope (or wire) tied the Earth and the Moon together?

    Results (751 votes), past polls