NAME    [Toc]    [Back]

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

LIBRARY    [Toc]    [Back]

     Math Library (libm, -lm)

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() and copysignf() return x with its sign changed to y's.

     finite() and finitef() return the value 1 just when -infinity < x <
     +infinity; otherwise a zero is returned (when |x| = infinity or x is
     NaN).

     ilogb() and ilogbf() return x's exponent, in integer format.
     ilogb(+-infinity) returns INT_MAX and ilogb(0) returns INT_MIN.

     nextafter() and nextafterf() return the next machine representable number
     from x in direction y.

     remainder() and remainderf() return 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.

     scalbn() and scalbnf() return x*(2**n) computed by exponent manipulation.

SEE ALSO    [Toc]    [Back]

     math(3)

HISTORY    [Toc]    [Back]

     The ieee functions appeared in 4.3BSD.

STANDARDS    [Toc]    [Back]

     IEEE Std 754-1985


FreeBSD 5.2.1		       February 25, 1994		 FreeBSD 5.2.1