>perl -e"use Devel::Peek; $x='123'; Dump($x); 0+$x; Dump($x);"
SV = PV(0x2369cc) at 0x182a22c
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x23fee4 "123"\0
  CUR = 3
  LEN = 4
SV = PVIV(0x182005c) at 0x182a22c
  REFCNT = 1
  FLAGS = (IOK,POK,pIOK,pPOK)
  IV = 123
  PV = 0x23fee4 "123"\0
  CUR = 3
  LEN = 4