char *                  T_PV
const char *            T_PV
void *                  O_OBJECT
int                     T_IV
INPUT
T_IV
        $var = (((SvIOK($arg)) || (SvNOK($arg)) || ((SvFLAGS($arg) & (SVf_OK & ~SVf_ROK)) && looks_like_number($arg))) ? ($type)SvIV($arg) : -1)
T_PV
        $var = ((SvFLAGS($arg) & (SVf_OK & ~SVf_ROK)) ? ($type)SvPV_nolen($arg) : NULL)
O_OBJECT
        $var = (sv_isobject($arg) ? ($type)SvIV((SV*)SvRV( $arg )) : NULL);