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Re: When <> fails

by pc88mxer (Vicar)
on Jul 29, 2008 at 19:32 UTC ( #700904=note: print w/replies, xml ) Need Help??


in reply to When <> fails

The current file handle that <> is using is stored in ARGV, but my testing shows that perl has alrady closed ARGV when the while (<>) {...} loop terminates.

You might try checking $! to see if that gets set when the NFS server stops serving the file:

while (<>) { ... } # check $! which is probably from the last close
Update: ikegami pointed out that testing $! (as in if ($!) ... doesn't make sense here.

One issue is that $! is only set when there is an error. One way around this is to force a known error at the end of the loop so that you can tell if readline generated an error.

Update 2: One can assign to $!, so this should be able to detect if readline failed:

while (<>) { ... $! = undef; } if (defined($!)) { # $! contains error from last <c>close
} </c>

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[marioroy]: IPC in MCE::Shared can handle 400k (sends) per second. That's seems a lot for being a pure-Perl module. After making the release, will come back and post a solution for a node by a fellow wanting faster logging.
[Corion]: While working on WWW::Mechanize:: Chrome, I had the suspicion that AnyEvent was doing something wrong, but I was able to swap it out for Mojolicious and the error persisted.
[Corion]: Of course, the error was in my own code ;)
[marioroy]: Corion, start and start_child in MCE::Hobo::Manager return a MCE::Hobo object, whereas P::FM returns the PID. I can have it return the PID though. I tried Hobo::Manager with several P::FM modules, just changed P::FM to MCE::Hobo::Manager and it works.
[marioroy]: I also have a Hobo driver for Forklift allowing folks to use in multiple classes, no conflicts with one another. That's not possible for P::FM.
[Discipulus]: congrats marioroy!
[marioroy]: CORE::wait works well eventhough multiple instances or classes using Hobo::Manager.
[Corion]: marioroy: I'm not sure what the normal use for the PID is in P:FM, but I guess that most programs just ignore or log it
[Corion]: Oh, yes, programs could call wait $pid, but if your $pid is an object, then you could add a ->wait method to it and wait $pid would call that automatically "thanks" to indirect object notation
[marioroy]: Just documentation edits is all that remains. Hobo::Simple provides foreach and forseq with identifier capability -- all transparently supporting array, hash, file handle, and seq 1 .. N.

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