logb, logbf, logbl, _logb, _logbf
Extracts the exponent value of a floating-point argument.
double logb( double x ); float logb( float x ); // C++ only long double logb( long double x ); // C++ only float logbf( float x ); long double logbl( long double x ); double _logb( double x ); float _logbf( float x );
A floating-point value.
logb returns the unbiased exponent value of x as a signed integer represented as a floating-point value.
The logb functions extract the exponential value of the 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.
Because C++ allows overloading, you can call overloads of logb that take and return float or long double values. In a C program, logb always takes and returns a double.
|Input||SEH exception||Matherr exception|
|logb, logbf, logbl, _logbf||<math.h>|
For more compatibility information, see Compatibility.
All versions of the C run-time libraries.