ieee_functions man page on DigitalUNIX

```ieee_functions(3)					     ieee_functions(3)

NAME
copysign,  finite, fp_class, isnan, nextafter, unordered - Related mis‐
cellaneous IEEE arithmetic functions.

SYNOPSIS
#include <math.h>

double copysign(
double x,
double y ); float copysignf(
float x,
float y ); long double copysignl(
long double x,
long double y ); int finite(
double x ); int finitef(
float x ); int finitel(
long double x ); int fp_class(
double x ); int fp_classf(
float x ); int fp_classl(
long double x ); int isnan(
double x ); int isnanf(
float x ); int isnanl(
long double x ); double nextafter(
double x,
double y ); float nextafterf(
float x,
float y ); long double nextafterl(
long double x,
long double y ); int unordered(
double x,
double y ); int unorderedf(
float x,
float y ); int unorderedl(
long double x,
long double y );

LIBRARY
Math Library (libm)

STANDARDS
Interfaces documented on this reference page conform to industry	 stan‐
dards as follows:

isnan():	 XPG4

nextafter():  XPG4-UNIX

industry standards and associated tags.

DESCRIPTION
The copysign(), copysignf(), and copysignl() functions  return  x  with
the same sign as y. IEEE 754 requires copysign(x,NaN), copysignf(x,NaN)
and copysignl(x,NaN) to return +x or -x.

The finite(), finitef(), and finitel()  functions  return  the  integer
value  1	 (True)	 or  0 (False).	 The finite(x), finitef(x),  and fini‐
tel(x) functions return 1 when -infinity < x< +infinity. They return  0
when |x| = infinity or x is a NaN.

The  fp_class(),	 fp_classf(),  and fp_classl() functions determine the
class of an IEEE floating-point value. They return one of the constants
in the file <fp_class.h> and never cause an exception, even for signal‐
ing NaNs. These routines implement the recommended function class(x) in
the  appendix  of  the IEEE 754-1985 standard for binary floating-point
arithmetic. The	constants  in  <fp_class.h>  refer  to	the  following
classes of values:

─────────────────────────────────────────────
Constant	       Class
─────────────────────────────────────────────
FP_SNAN	       Signaling NaN (Not-a-Number)
FP_QNAN	       Quiet NaN (Not-a-Number)
FP_POS_INF      +infinity
FP_NEG_INF      -infinity
FP_POS_NORM     Positive normalized
FP_NEG_NORM     Negative normalized
FP_POS_DENORM   Positive denormalized
FP_NEG_DENORM   Negative denormalized
FP_POS_ZERO     +0.0 (positive zero)
FP_NEG_ZERO     -0.0 (negative zero)
─────────────────────────────────────────────

The isnan(), isnanf(), and isnanl() functions return the value 1 (True)
if x is NaN (the IEEE floating point reserved not-a-number value); oth‐
erwise, it returns the value 0 (False).

The  nextafter(),  nextafterf(),	 and nextafterl() functions return the
next machine-representable number from x in the direction of y.

The unordered(), unorderedf(), and unorderedl()	functions  return  the
value 1 (True) if either x or y or both is a NaN; otherwise, it returns
the value 0 (False).

drem(3),	 logb(3),  scalb(3),  rint(3),	sqrt(3),  and  ANSI/IEEE   Std
754-1985, IEEE Standard for Binary Floating-Point Arithmetic

ieee_functions(3)
```
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