IEEE_TEST(3)

IEEE_TEST(3) | 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 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

August 3, 2011 | NetBSD 10.1