drem(3m)                   DG/UX 4.30                    drem(3m)



     NAME
          drem - IEEE floating-point remainder

     SYNOPSIS
          #include <ieeefp.h>     /* for IEEE environment */

          or

          #include <math.h>       /* for System V environment */

          double drem (x,y)
          double x, y;

     DESCRIPTION
          Drem returns the remainder of x/y as specified by IEEE
          Standard 754 for Binary Floating-Point Arithmetic.  The
          remainder r is calculated as

            r = x - n * y

          where n is the integer nearest the exact value of x/y.  If
          the absolute value of x/y is .5, then n is the even integer
          nearest the result of x/y.  Since the IEEE standard requires
          that the exact value of x/y be used in the calculation, the
          'round nearest' rounding mode is in effect throughout the
          execution of the drem function.  The remainder is always
          considered to be exact, so inexact exceptions are never
          raised.

     SEE ALSO
          fpgetround(3C), isnan(3C).

     DIAGNOSTICS
          The IEEE standard defines drem(x, 0) and drem(infinity, y)
          to be invalid operations.  In addition, this implementation
          considers drem(x, y) to be an invalid operation when x/y
          results in infinity or double-precision overflow.  These
          operations raise an 'invalid operation' exception, which
          results in signal SIGFPE if traps are enabled and a NaN
          otherwise.

     BUGS
          This implementation of drem does not allow exceptional
          values to be fixed by a trap handler.











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