Table 7-3 Class and sign inquiry macros
Macro | Value returned | Condition |
fpclassify(x) | FP_SNAN | x is a signaling NaN |
| FP_QNAN | x is a quiet NaN |
| FP_INFINITE | x is
or + |
| FP_ZERO | x is +0 or
|
| FP_NORMAL | x is a normalized number |
| FP_SUBNORMAL | x is a denormalized (subnormal) number |
isnormal(x) | TRUE | x is a normalized number |
isfinite(x) | TRUE | x is not
, + , or NaN |
isnan(x) | TRUE | x is a NaN (quiet or signaling) |
signbit(x) | 1 | The sign bit of x is 1 (x is negative) |
| 0 | The sign bit of x is 0 (x is positive) |