Re: How to get the variable or function address in memory?

[rcaputo]

The memory address is the numeric version of the reference. Some sample code follows. As an added bonus, it illustrates the use of the mysterious "P" unpack() template.

#!/usr/bin/perl -wl

use strict;

my $target = 'IHBT';

print "target contains       : ``$target''";

# Numify the reference, and derive a pointer from it.

my $target_address = \$target + 0;
my $native_version = pack 'L', $target_address;
my $pointer        = pack 'P', $native_version;

print "target address        : ", sprintf('%x', $target_address);

# Walk Perl's variable structures.
# This code depends on Perl's current implementation.  I advise
# against using it in production code.

my $sv = unpack('P4', $native_version);
print "deref'd packed (sv)   : ", sprintf('%x', unpack('L', $sv));

my $pv = unpack('P4', $sv);
print "deref'd sv (pv)       : ", sprintf('%x', unpack('L', $pv));

my $value = unpack('P' . length($target), $pv);
print "deref'd pv (value)    : ``$value''\n";

-- Rocco Caputo - http://poe.perl.org/