SvPVIV – string & integer 

$t = 0 + $s;
SV = PVIV(0x2454db8) at 0x2460aa8
  REFCNT = 1
  FLAGS = (IOK,POK,pIOK,pPOK)
  IV = 42
  PV = 0x2459cf0 "42"\0
  CUR = 2
  LEN = 16