c:\@Work\Perl\monks>perl -wMstrict -le
"use Data::Dump qw(pp);
 ;;
 sub clear_it {
   my($data) = @_;
   print 'in clear_it(): A: ref address: ', $data;
   @$data = ();
   print 'in clear_it(): B: ref address: ', $data;
   }
 ;;
 my $data = ['a','b'];
 print 'in main: X: ref address: ', $data;
 ;;
 clear_it($data);
 print 'in main: Y: ref address: ', $data;
 print 'in main: Z: ref content: ', pp $data;
"
in main: X: ref address: ARRAY(0x1846f3c)
in clear_it(): A: ref address: ARRAY(0x1846f3c)
in clear_it(): B: ref address: ARRAY(0x1846f3c)
in main: Y: ref address: ARRAY(0x1846f3c)
in main: Z: ref content: []