use strict;
use File::Path 'mkpath';
use Data::Dumper;

mkpath( 'a:/tmp', {error => \my $err});
@$err and print Dumper($err);

__PRODUCES__
$VAR1 = [
  {
    'a:/' => 'Permission denied; The device is not ready'
  },
  {
    'a:/tmp' => 'Permission denied; The device is not ready'
  }
];