But what happens when you want to pass a format or dirhandle to a subroutine instead of a filehandle.
Although globs are synonymous with filehandles they aren't really the same thing. It's just that perl will DWYM when you provide a reference to a glob with an IO reference in it 
$FH = "a scalar";
@FH = qw/an array/;
%FH = (a => 'hash');
open(FH, "somefile.txt") or die("dang - $!");
for(qw/SCALAR ARRAY HASH IO/) {
  print $glob, "{$_} = ', *{$glob}{$_}, $/;
}
print while <$glob>;

__output__

*main::FH{SCALAR} = SCALAR(0x80fd44c)
*main::FH{ARRAY} = ARRAY(0x80fd464)
*main::FH{HASH} = HASH(0x80fd4a0)
*main::FH{IO} = IO::Handle=IO(0x80fd4dc)
foo
bar
baz
quux

[download]
So if you use a glob or a reference to a glob where a filehandle is expected and the glob doesn't contain a valid IO reference then it evaluates to undef e.g 
$main::FH = 'a string';
print "nope" if not defined *FH{IO};

__output__

nope

[download]

HTH

_________
broquaint

In reply to Re: typeglob questions by broquaint
in thread typeglob questions by princepawn

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