NAME
logb, logbf,
logbl, scalb,
scalbf, significand,
significandf —
IEEE test functions
LIBRARY
library “libm”
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
STANDARDS
IEEE Std 754-1985