Using the Reference

• What's it a reference to?

  SvTYPE(SvRV(rv))
  

• Must cast return from SvRV before using it

   AV *a; SV *rv;
    /* ensure it's an array ref */
    if (SvTYPE(SvRV(rv)) != SVt_PVAV) { ... }
    a = (AV*) SvRV(rv);	/* get the array ref */