logb.c File Reference

#include "../math.h"

Functions
double	logb (double x)
	Compute logarithm using FLT_RADIX. More...

Function Documentation

logb()

double logb

(

double

x

)

Compute logarithm using FLT_RADIX.

The logb functions extract the exponent of x, as a signed integer value in floating-point format. If x is subnormal it is treated as though it were normalized; thus, for positive finite x, 1 ≤ x × FLT_RADIX^(−log_b(x)) < FLT_RADIX. A domain error or pole error may occur if the argument is zero.

Parameters

x	Value whose logarithm is calculated.

Returns

The logb functions return the signed exponent of x.