Re: Detecting filehandles

Subotai <subotai@xxxxxxx> wrote:

Is there a way to detect if an argument you are passed in a subroutine is a
filehandle?


No, because it is not possible to pass a filehandle as a
subroutine argument.


For instance:

open(FILE, '/file');
foo(\*FILE);


That is not passing a filehandle.

That is passing a reference to a typeglob.


foo($someotherarg);

sub foo {
$arg = shift;
#### do some check on $arg to see if it is a filehandle or a normal scalar

if ( ref($arg) eq 'GLOB' )
{ print "arg is a glob\n" }
else
{ print "arg is NOT a glob\n" }


}

Also if you have an open filehandle, is there a way to see what file it is
referencing?


A "filehandle" does not correspond to a "file". They are different things.

A filehandle corresponds to an input/output channel.

A filehandle might correspond to a file, but it might correspond
to any of several other things instead.

What file would you report for:

open FILE, 'echo "Hello World" |' or die ...
foo(\*FILE);
or
foo(\*STDOUT);

??


--
Tad McClellan SGML consulting
tadmc@xxxxxxxxxxxxxx Perl programming
Fort Worth, Texas
.

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