#!/pro/bin/perl

use 5.18.3;
use warnings;

use Config;
use Fcntl;

printf "Perl $^V %s ivsize %d byteorder %d\n",
    @Config{qw( archname ivsize byteorder )};

# Generate a "binary file" with a string of bytes likely to show up is
+sues in
# decoding
my $binary = "\x91\x34\x33\x90\x81\x32\x31\x80";

for ([ "BE32" => "I>I>" ],
     [ "LE32" => "I<I<" ],
     [ "BE64" => "Q>"   ],
     [ "LE64" => "Q<"   ],
     ) {

    my ($type, $format) = @$_;
    my $data = pack $format => 0, 0;

    open my $fh, "<", \$binary;
    read $fh, $data, length $data;
    my @x = unpack $format => $data;

    if (@x == 2) {
        printf "%s\: %08x%08x\n", $type, @x;
        }
    else {
        printf "%s\: %016x\n",    $type, @x;
        }
    }
[download]

=>

BE32: 9134339081323180
LE32: 9033349180313281
BE64: 9134339081323180
LE64: 8031328190333491
[download]