IEEE_TEST(3)

IEEE_TEST(3) | NetBSD Library Functions Manual | IEEE_TEST(3)

# 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 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.

scalbn(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

August 3, 2011 | NetBSD 5.99