fp_class(3) [ultrix man page]

fp_class(3)						     Library Functions Manual						       fp_class(3)

Name
       fp_class - classes of IEEE floating-point values

Syntax
       #include <fp_class.h>

       int fp_class_d(double x);
       int fp_class_f(float x);

Description
       These routines are used to determine the class of IEEE floating-point values.  They return one of the constants in the file and never cause
       an exception, even for signaling NaNs.  These routines are to implement the recommended function class(x)  in  the  appendix  of  the  IEEE
       754-1985 standard for binary floating-point arithmetic.	The constants in 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     +oo (positive infinity)
       FP_NEG_INF     -oo (negative infinity)
       FP_POS_NORM    positive normalized nonzero
       FP_NEG_NORM    negative normalized nonzero
       FP_POS_DENORM  positive denormalized
       FP_NEG_DENORM  negative denormalized
       FP_POS_ZERO    +0.0 (positive zero)
       FP_NEG_ZERO    -0.0 (negative zero)

Also See
       ANSI/IEEE Std 754-1985, IEEE Standard for Binary Floating-Point Arithmetic

								       RISC							       fp_class(3)

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)