__FPR
fpsetround(__FPR(round));
FP_RN=__FPR(FE_TONEAREST), /* round to nearest representable number */
FP_RZ=__FPR(FE_TOWARDZERO), /* round to zero (truncate) */
FP_RM=__FPR(FE_DOWNWARD), /* round toward negative infinity */
FP_RP=__FPR(FE_UPWARD) /* round toward positive infinity */
FP_RN=__FPR(FE_TONEAREST), /* round to nearest representable number */
FP_RZ=__FPR(FE_TOWARDZERO), /* round to zero (truncate) */
FP_RP=__FPR(FE_UPWARD), /* round toward positive infinity */
FP_RM=__FPR(FE_DOWNWARD) /* round toward negative infinity */