osx man page for logb

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