Extracts an exponential value of a double-precision floating-point argument.
double _logb(
   double x 
);
Parameters
- x
 Double-precision floating-point value.
Return Value
_logb returns the unbiased exponential value of x.
Remarks
The _logb function extracts the exponential value of its double-precision floating-point argument x, as though x were represented with infinite range. If the argument x is denormalized, it is treated as if it were normalized.
| Input | SEH exception | Matherr exception | 
|---|---|---|
| ± QNAN,IND | None | _DOMAIN | 
| ± 0 | ZERODIVIDE | _SING | 
Requirements
| Routine | Required header | 
|---|---|
| _logb | <float.h> | 
For more compatibility information, see Compatibility in the Introduction.
Libraries
All versions of the C run-time libraries.
.NET Framework Equivalent
Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.