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   ieee_functions(3M)      (BSD Compatibility Package)      ieee_functions(3M)


   NAME
         ieeefunctions, fpclass, isnan, copysign, scalbn - miscellaneous
         functions for IEEE arithmetic

   SYNOPSIS
         cc [ flag... ] file ... -lucb
         #include <fp.h>
         #include <math.h>
         #include <stdio.h>

         enum fpclasstype fpclass(x)
         double x;

         int isnan(x)
         double x;

         double copysign(x,y)
         double x, y;

         double scalbn(x,n)
         double x; int n;

   DESCRIPTION
         Most of these functions provide capabilities required by ANSI/IEEE
         Std 754-1985 or suggested in its appendix.

         fpclass(x) corresponds to the IEEE's class() and classifies x as
         zero, subnormal, normal, oo, or quiet or signaling NaN;
         /usr/ucbinclude/sys/ieeefp.h defines enum fpclasstype.  The
         following function returns 0 if the indicated condition is not
         satisfied:

               isnan(x)       returns 1 if x is NaN

         copysign(x,y) returns x with y's sign bit.

         scalbn(x,n) returns x* 2**n computed by exponent manipulation rather
         than by actually performing an exponentiation or a multiplication.
         Thus

               1 < scalbn(fabs(x),-ilogb(x)) < 2

         for every x except 0, infinity, and NaN.

   FILES
         /usr/ucbinclude/sys/ieeefp.h
         /usr/ucbinclude/math.h
         /usr/include/values.h





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