LOGB(3) OpenBSD Programmer's Manual LOGB(3)NAME
logb, logbf, logbl, scalb, scalbf, significand, significandf - IEEE test
functions
SYNOPSIS
#include <math.h>
double
logb(double x);
float
logbf(float x);
long double
logbl(long double x);
double
scalb(double x, double n);
float
scalbf(float x, float n);
double
significand(double x);
float
significandf(float x);
DESCRIPTION
These functions allow users to test conformance to IEEE Std 754-1985.
Their use is not otherwise recommended.
logb(x) returns x's exponent n, a signed integer converted to
double-precision floating-point. logb(+-infinity) = +infinity; logb(0) =
-infinity with a division by zero exception. logbf() is the single
precision form of logb(). logbl() is the extended precision form of
logb().
scalb(x, n) returns x*(2**n) computed by exponent manipulation. scalbf()
is the single precision form of scalb().
significand(x) returns sig, where x := sig * 2**n with 1 <= sig < 2.
significand(x) is not defined when x is 0, +-infinity, or NaN.
significandf() is the single precision for of significand().
SEE ALSOilogb(3), math(3), scalbn(3)STANDARDS
IEEE Std 754-1985
OpenBSD 4.9 August 3, 2009 OpenBSD 4.9
