Edit File: warndie.pl
#!/usr/bin/perl -w require Error; if( $ARGV[0] ) { import Error qw( :warndie ); print "Imported the :warndie tag.\n"; print "\n"; } else { print "Running example without the :warndie tag.\n"; print "Try also passing a true value as \$ARGV[0] to import this tag\n"; print "\n"; } sub inner { shift->foo(); } sub outer { inner( @_ ); } outer( undef );