Variable "$var" will not stay shared at sub_in_sub.pl line 23.
calling outter from main:
  outter: 0
    calling inner, should increment 0 -> 1
    inner: 0 -> 1
calling inner from main:
    inner: 1 -> 2
calling outter from main:
  outter: 0
    calling inner, should increment 0 -> 1
    inner: 2 -> 3