unordered(3) [osf1 man page]

ieee_functions(3)					     Library Functions Manual						 ieee_functions(3)

NAME

       copysign, finite, fp_class, isnan, nextafter, unordered	- Related miscellaneous IEEE arithmetic functions.

LIBRARY

       Math Library (libm.a)

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);

STANDARDS

       Interfaces documented on this reference page conform to industry standards as follows:

       isnan():  XPG4

       nextafter():  XPG4-UNIX

       Refer to the standards(5) reference page for more information about 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), copy-
       signf(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 finitel(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  con-
       stants  in  the	file <fp_class.h> and never cause an exception, even for signaling 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);
       otherwise, 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).

RELATED INFORMATION

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

																 ieee_functions(3)

Check Out this Related Man Page

ieee(3m)																  ieee(3m)

Name
       copysign, drem, finite, logb, scalb - copysign, remainder, exponent manipulations

Syntax
       #include <math.h>

       double copysign(x,y)
       double x,y;

       double drem(x,y)
       double x,y;

       int finite(x)
       double x;

       double logb(x)
       double x;

       double scalb(x,n)
       double x;
       int n;

Description
       These functions are required, or recommended by the IEEE standard 754 for floating-point arithmetic.

       The function returns x with its sign changed to y's.

       The function returns the remainder r := x - n*y where n is the integer nearest the exact value of x/y.  Additionally if |n-x/y|=1/2, then n
       is even.  Consequently the remainder is computed exactly and |r| <= |y|/2.  Note that is the exception (see Diagnostics).

       Finite(x) = 1 just when -infinity < x < +infinity,
		 = 0 otherwise (when |x| = infinity or x is NaN)

       The a signed integer converted to double-precision floating-point and so chosen that 1 <= |x|/2**n < 2 unless x = 0 or |x| = infinity or  x
       lies between 0 and the Underflow Threshold.

       Scalb(x,n) = x*(2**n) computed, for integer n, without first computing 2**N.

Diagnostics
       IEEE 754 defines drem(x,0) and drem(infinity,y) to be invalid operations that produce a NaN.

       IEEE 754 defines logb(+-infinity) = +infinity and logb(0) = -infinity, requires the latter to signal Division-by-Zero.

Restrictions
       IEEE 754 currently specifies that logb(denormalized no.) = logb(tiniest normalized no. > 0) but the consensus has changed to the specifica-
       tion in the new proposed IEEE standard p854, namely that logb(x) satisfy
	      1 <= scalb(|x|,-logb(x)) < Radix	 ... = 2 for IEEE 754
       for every x except 0, infinity and NaN.	Almost every program that assumes 754's specification will work correctly if  logb  follows  854's
       specification instead.

       IEEE 754 requires copysign(x,NaN) = +-x	but says nothing else about the sign of a NaN.

See Also
       floor(3M), fp_class(3), math(3M)

								       RISC								  ieee(3m)

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