mt_state*  O_OBJECT
int32_t    T_IV
uint32_t   T_UV
int64_t    T_IV
uint64_t   T_UV

OUTPUT
O_OBJECT
  sv_setref_pv( $arg, CLASS, (void*)$var );

INPUT
O_OBJECT
  if( sv_isobject($arg) && (SvTYPE(SvRV($arg)) == SVt_PVMG) )
    $var = ($type)SvIV((SV*)SvRV( $arg ));
  else {
    warn( \"${Package}::$func_name() -- $var is not a blessed SV reference\" );
    XSRETURN_UNDEF;
  }
