NAME    [Toc]    [Back]

     copysign,  copysignf,  finite,   finitef,   ilogb,   ilogbf,
nextafter,
     nextafterf,  remainder,  remainderf, scalbn, scalbnf - functions for IEEE
     arithmetic

SYNOPSIS    [Toc]    [Back]

     #include <math.h>

     double
     copysign(double x, double y);

     float
     copysignf(float x, float y);

     int
     finite(double x);

     int
     finitef(float x);

     int
     ilogb(double x);

     int
     ilogbf(float x);

     double
     nextafter(double x, double y);

     float
     nextafterf(float x, float y);

     double
     remainder(double x, double y);

     float
     remainderf(float x, float y);

     double
     scalbn(double x, int n);

     float
     scalbnf(float x, int n);

DESCRIPTION    [Toc]    [Back]

     These functions are required  or  recommended  by  IEEE  Std
754-1985.

     copysign()  returns  x  with  its  sign changed to y's.  The
copysignf() function
 is a single precision version of copysign().

     finite() returns the value 1 just when -Infinity < x <  +Infinity; otherwise
  a  zero  is returned (when |x| = Infinity or x is NaN.
The finitef()
     function is a single precision version of finite().

     ilogb()  returns  x's  exponent  n,   in   integer   format.
ilogb(+-Infinity) returns
  INT_MAX  and  ilogb(0) returns INT_MIN.  The ilogbf()
function is a
     single precision version of ilogb().

     nextafter() returns the next  machine  representable  number
from x in direction
  y.  The nextafterf() function is a single precision
version of
     nextafter().

     remainder() returns the remainder r := x - n*y  where  n  is
the integer
     nearest  the exact value of x/y; moreover if |n - x/y| = 1/2
then n is
     even.  Consequently, the remainder is computed  exactly  and
|r| <= |y|/2.
     But  remainder(x,  0) and remainder(Infinity, 0) are invalid
operations
     that produce a NaN.  The remainderf() function is  a  single
precision version
 of remainder().

     scalbn() returns x*(2**n) computed by exponent manipulation.
The
     scalbnf()  function  is  a  single  precision   version   of
scalbn().

SEE ALSO    [Toc]    [Back]

     math(3)

STANDARDS    [Toc]    [Back]

     IEEE Std 754-1985

HISTORY    [Toc]    [Back]

     The ieee functions appeared in 4.3BSD.

OpenBSD      3.6                        February     25,     1994