ieee_functions(3BSD) (BSD System Compatibility) ieee_functions(3BSD)
NAME
ieee_functions, fp_class, isnan, copysign, scalbn - (BSD)
miscellaneous functions for IEEE arithmetic
SYNOPSIS
/usr/ucb/cc [flag . . . ] file . . .
#include <fp.h>
#include <math.h>
#include <stdio.h>
enum fp_class_type fp_class(double x);
int isnan(double x);
double copysign(double x, double y);
double scalbn(double x, int n);
DESCRIPTION
Most of these functions provide capabilities required by
ANSI/IEEE Std 754-1985 or suggested in its appendix.
fp_class(x) corresponds to the IEEE's class() and classifies x
as zero, subnormal, normal, oo, or quiet or signaling NaN;
/usr/ucbinclude/sys/ieeefp.h defines enum fp_class_type. The
following function returns 0 if the indicated condition is not
satisfied:
isnan(x) returns 1 if x is NaN
copysign(x,y) returns x with y's sign bit.
scalbn(x,n) returns x* 2**n computed by exponent manipulation
rather than by actually performing an exponentiation or a
multiplication. Thus
1 < scalbn(fabs(x),-ilogb(x)) < 2
for every x except 0, infinity, and NaN.
FILES
/usr/ucbinclude/sys/ieeefp.h
/usr/ucbinclude/math.h
/usr/include/values.h
Copyright 1994 Novell, Inc. Page 1