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ieee_functions(3)
NAME
  copysign, finite, fp_class, isnan, nextafter, unordered - Related
  miscellaneous 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 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), 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 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 constants 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).

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

Index for Section 3

Alphabetical listing for I

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