ilogb(), ilogbf() -- compute integral exponent of number

SYNOPSIS

#include <math.h>

int ilogb(double x)

int ilogbf(float x)

The ilogb() function returns the exponent part of x. Formally, the return value is the integral part of log_r|x| as a signed integral value, for non-zero x, where r is the radix of the machine's floating point arithmetic.

The call ilogb(x) is equivalent to (int)logb(x).

The ilogbf() function is a single-precision version of ilogb().

PARAMETERS

x: Is the number whose exponent is to be returned.

RETURN VALUES

On success, ilogb() returns the exponent part of x. If x is 0, then ilogb() returns -INT_MAX. If x is NaN, +Infinity, or -Infinity, ilogb() returns INT_MAX.

CONFORMANCE

UNIX 98

MULTITHREAD SAFETY LEVEL

MT-Safe.

PORTING ISSUES

None.

AVAILABILITY

PTC MKS Toolkit for Professional Developers
PTC MKS Toolkit for Professional Developers 64-Bit Edition
PTC MKS Toolkit for Enterprise Developers
PTC MKS Toolkit for Enterprise Developers 64-Bit Edition

ilogb(), ilogbf()
compute integral exponent of number

Function