NAME
logb,
logbf,
logbl,
scalb,
scalbf,
significand,
significandf —
IEEE test functions
LIBRARY
Math Library (libm, -lm)
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 otherwise not 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.
scalb(
x,
n)
returns
x∗(2**
n) computed by
exponent manipulation.
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.
SEE ALSO
math(3)
STANDARDS
IEEE Std 754-1985