fpgetround(3C)                                        fpgetround(3C)


       NAME
             fpgetround, fpsetround, fpgetmask, fpsetmask, fpgetsticky,
             fpsetsticky - IEEE floating-point environment control

       SYNOPSIS
             include <ieeefp.h>
             fp_rnd fpgetround(void);
             fp_rnd fpsetround(fp_rnd rnd_dir);
             fp_except fpgetmask(void);
             fp_except fpsetmask(fp_except mask);
             fp_except fpgetsticky(void);
             fp_except fpsetsticky(fp_except sticky);

       DESCRIPTION
             There are five floating-point exceptions: divide-by-zero,
             overflow, underflow, imprecise (inexact) result, and invalid
             operation.  When a floating-point exception occurs, the
             corresponding sticky bit is set, and if the mask bit is
             enabled, the trap takes place.  These routines let the user
             change the behavior on occurrence of any of these exceptions,
             as well as change the rounding mode for floating-point
             operations.

                   FP_X_INV     /* invalid operation exception */
                   FP_X_OFL     /* overflow exception */
                   FP_X_UFL     /* underflow exception */
                   FP_X_DZ      /* divide-by-zero exception */
                   FP_X_IMP     /* imprecise (loss of precision) */
                   FP_RN        /* round to nearest representative number */
                   FP_RP        /* round to plus infinity */
                   FP_RM        /* round to minus infinity */
                   FP_RZ        /* round to zero (truncate) */

             fpgetround returns the current rounding mode.

             fpsetround sets the rounding mode and returns the previous
             rounding mode.

             fpgetmask returns the current exception masks.

             fpsetmask sets the exception masks and returns the previous
             setting.

             fpgetsticky returns the current exception sticky flags.




                           Copyright 1994 Novell, Inc.               Page 1

      fpgetround(3C)                                        fpgetround(3C)


            fpsetsticky sets (clears) the exception sticky flags and
            returns the previous setting.

            The default environment is rounding mode set to nearest
            (FP_RN) and all traps disabled.

            Individual bits may be examined using the constants defined in
            ieeefp.h.

      REFERENCES
            isnan(3C)

      NOTICES
            fpsetsticky modifies all sticky flags.  fpsetmask changes all
            mask bits.  fpsetmask clears the sticky bit corresponding to
            any exception being enabled.

            C requires truncation (round to zero) for floating point to
            integral conversions.  The current rounding mode has no effect
            on these conversions.

            One must clear the sticky bit to recover from the trap and to
            proceed.  If the sticky bit is not cleared before the next
            trap occurs, a wrong exception type may be signaled.
























                          Copyright 1994 Novell, Inc.               Page 2