macro FLT_RADIX constant FLT_ROUNDS macro FLT_MANT_DIG macro DBL_MANT_DIG macro LDBL_MANT_DIG macro FLT_DIG macro DBL_DIG macro LDBL_DIG macro FLT_MIN_EXP macro DBL_MIN_EXP macro LDBL_MIN_EXP macro FLT_MIN_10_EXP macro DBL_MIN_10_EXP macro LDBL_MIN_10_EXP macro FLT_MAX_EXP macro DBL_MAX_EXP macro LDBL_MAX_EXP macro FLT_MAX_10_EXP macro DBL_MAX_10_EXP macro LDBL_MAX_10_EXP macro FLT_MAX macro DBL_MAX macro LDBL_MAX macro FLT_EPSILON macro DBL_EPSILON macro LDBL_EPSILON macro FLT_MIN macro DBL_MIN macro LDBL_MIN allow *_t