simple_double T_S_DOUBLE
extra_simple_double T_XS_DOUBLE

INPUT
T_S_DOUBLE
          $var = (simple_double)SvNV($arg)

T_XS_DOUBLE
          $var = (simple_double)SvNV($arg)

OUTPUT
T_S_DOUBLE
          sv_setnv($arg, (simple_double)$var);

T_XS_DOUBLE
          sv_setnv($arg, (simple_double)$var);