http://www.perlmonks.org?node_id=167482


in reply to Is it possible to do pass by reference in Perl?

It is possible to pass by reference in perl. The argument list u get inside ur subroutine via @_ are implicit reference to values that were passed in from inside from outside.i.e. if u pass in a list of strings, inside the body of the sub,change those strings,then they will be modified outside the subroutine.
sub ted { my($add,$sub,$mul) = @_; ... .. }