logb(3) BSD Library Functions Manual logb(3)
NAME
logb -- return exponent as a floating-point number
SYNOPSIS
#include <math.h>
double
logb(double x);
long double
logbl(long double x);
float
logbf(float x);
DESCRIPTION
The logb() functions return the exponent of x, represented as a floating-
point number.
SPECIAL VALUES
logb(+-0) returns -infinity and raises the "divide-by-zero" floating-
point exception.
logb(+-infinity) returns +infinity.
VECTOR OPERATIONS
If you need to apply the logb() functions to SIMD vectors or arrays,
using the following functions provided by the Accelerate.framework may
give significantly better performance:
#include <Accelerate/Accelerate.h>
vFloat vlogbf(vFloat x);
void vvlogbf(float *y, const float *x, const int *n);
void vvlogb(double *y, const double *x, const int *n);
SEE ALSO
ilogb(3) log(3) math(3)
STANDARDS
The logb() functions conform to ISO/IEC 9899:2011.
BSD August 21, 2012 BSD
Mac OS X 10.9.1 - Generated Wed Jan 8 19:38:05 CST 2014