use strict; use warnings; package TestPDL; my $PDLLoaded = eval { require 'PDL.pm'; PDL->import (); 1; }; sub new { my ($class, %params) = @_; $params{havePDL} = $PDLLoaded; return bless \%params, $class; } package main; my $obj = TestPDL->new (); my $obj2 = TestPDL->new (); print $obj2->{havePDL} ? "Have PDL available" : "PDL not present or object create failed";