IEEE(3) BSD Library Functions Manual IEEE(3)NAME
copysign, copysignf, finite, finitef, ilogb, ilogbf, nextafter,
nextafterf, remainder, remainderf, scalbn, scalbnf — functions for IEEE
arithmetic
LIBRARY
Math Library (libm, -lm)
SYNOPSIS
#include <math.h>
double
copysign(double x, double y);
float
copysignf(float x, float y);
int
finite(double x);
int
finitef(float x);
int
ilogb(double x);
int
ilogbf(float x);
double
nextafter(double x, double y);
float
nextafterf(float x, float y);
double
remainder(double x, double y);
float
remainderf(float x, float y);
double
scalbn(double x, int n);
float
scalbnf(float x, int n);
DESCRIPTION
These functions are required or recommended by IEEE Std 754-1985.
copysign() returns x with its sign changed to y's.
finite() returns the value 1 just when -∞ < x < +∞; otherwise a zero is
returned (when |x| = ∞ or x is NaN).
ilogb() returns x's exponent n, in integer format. ilogb(±∞) returns
INT_MAX and ilogb(0) returns INT_MIN.
nextafter() returns the next machine representable number from x in
direction y.
remainder() returns the remainder r := x - n∗y where n is the integer
nearest the exact value of x/y; moreover if |n - x/y| = ½ then n is even.
Consequently the remainder is computed exactly and |r| ≤ |y|/2. But
remainder(x, 0) and remainder(∞, 0) are invalid operations that produce a
NaN.
scalbn() returns x∗(2**n) computed by exponent manipulation.
SEE ALSOmath(3)STANDARDS
IEEE Std 754-1985
HISTORY
The ieee functions appeared in 4.3BSD.
BSD February 25, 1994 BSD
