NAME

ieee_functions, isnan, fabs, fmod, nextafter, remainder − appendix and related miscellaneous functions for IEEE arithmetic

SYNOPSIS

#include <math.h>

int isnan(double x);

double fabs(double x);

double nextafter(double x, double y);

double fmod(double x, double y);

double remainder(double x, double y);

DESCRIPTION

Most of these functions provide capabilities required by ANSI/IEEE Std 754-1985 or suggested in its appendix. 

isnan(x) returns 1 if x is NaN; otherwise it returns 0. 

fabs(x) returns the absolute value of x.

nextafter(x,y) returns the next machine representable number from x in the direction y.

remainder(x,y) and fmod(x,y) return a remainder of x with respect to y; that is, the result r is one of the numbers that differ from x by an integral multiple of y. Thus (x−r)/y is an integral value, even though it might exceed MAXINT, the largest int defined in <values.h> if it were explicitly computed as an int.  Both functions return one of the two such r smallest in magnitude.  remainder(x,y) is the operation specified in ANSI/IEEE Std 754-1985; the result of fmod(x,y) may differ from remainder’s result by ±y. The magnitude of remainder’s result cannot exceed half that of y; its sign might not agree with either x or y. The magnitude of fmod’s result is less than that of y; its sign agrees with that of x. Neither function can generate an exception as long as both arguments are normal or subnormal.

remainder(x,0), fmod(x,0), remainder(∞,y), and fmod(∞,y) are invalid operations that produce a NaN. 

FILES

/usr/include/math.h

/usr/include/values.h

/usr/ccs/lib/libm.a

SEE ALSO

matherr(3M)

SunOS 5.1/SPARC  —  Last change: 30 Apr 1992