Index for Section 3

Alphabetical listing for I

ieee_functions(3)
NAME
  copysign, finite, fp_class, isnan, nextafter, unordered  - Appendix and
  related miscellaneous functions for IEEE arithmetic

LIBRARY
  Math Library (libm.a)

SYNOPSIS
  #include <math.h>

  double copysign   (double x, double y);
  float	 copysignf  (float  x, float  y);
  int	 finite	    (double x);
  int	 finitef    (float  x);
  int	 fp_class   (double x);
  int	 fp_classf  (float  x);
  int	 isnan	    (double x);
  int	 isnanf	    (float  x);
  double nextafter  (double x, double y);
  float	 nextafterf (float  x, float  y);
  int	 unordered  (double x, double y);
  int	 unorderedf (float  x, float  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() and copysignf() functions return x with the same sign as y.
  IEEE 754 requires copysign(x,NaN) and copysignf(x,NaN) to return +x or -x.

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

  The fp_class() and fp_classf() functions determine the class of IEEE
  floating-point values.  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() and isnanf() 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() and nextafterf() functions return the next machine-
  representable number from x in the direction of y.

  The unordered() and unorderedf() 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