using a filehandle stored in a hash

DavidFerrington has asked for the wisdom of the Perl Monks concerning the following question:

I'm sure this is simple, but I just can't figure it out, I've looked at dereferencing and still don't get it. I have opened a file with open and stored the filehandle in a hash, now I want to print to the filehandle, but using the following code gives syntax error, presumably because the parser doesn't know the hash value is a filehandle.

our %hash;
...
open_file();
...
write_to_file();
...
sub open_file {
  open $hash{fh}, '<', 'myfile';
}
sub write_to_file {
  print $hash{fh} 'some line of data\n";
}

however, if I change the write_to_file sub to be

sub write_to_file {
  my $fh = $hash{fh};
  print  $fh 'some line of data\n";
}

that works, but I'd far rather do it the 'proper' way

-- David

Comment on using a filehandle stored in a hash

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Re: using a filehandle stored in a hash by FunkyMonk (Bishop) on Mar 28, 2010 at 11:08 UTC
Wrap the hash in a pair of braces: `my %hash; open $hash{fh}, '>', 'foo' or die $!; print {$hash{fh}} "foo"; # ^ ^` [download] Unless I state otherwise, all my code runs with strict and warnings	[reply] [d/l]
Re^2: using a filehandle stored in a hash by DavidFerrington (Acolyte) on Mar 28, 2010 at 11:18 UTC
DOH! so simple - I didn't think of that - thank you -- David	[reply]
Re: using a filehandle stored in a hash by toolic (Bishop) on Mar 28, 2010 at 12:52 UTC
You already have the solution, but here is how to get the solution: read the documentation of print: Note that if you're storing FILEHANDLEs in an array, or if you're using any other expression more complex than a scalar variable to retrieve it, you will have to use a block returning the filehandle value instead: `print { $files[$i] } "stuff\n";` [download]	[reply] [d/l]