FEGETROUND(3)              POSIX Programmer's Manual             FEGETROUND(3)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NAME
       fegetround, fesetround -- get and set current rounding direction

SYNOPSIS
       #include <fenv.h>

       int fegetround(void);
       int fesetround(int round);

DESCRIPTION
       The functionality described on this reference page is aligned with the
       ISO C standard. Any conflict between the requirements described here
       and the ISO C standard is unintentional. This volume of POSIX.1-2017
       defers to the ISO C standard.

       The fegetround() function shall get the current rounding direction.

       The fesetround() function shall establish the rounding direction
       represented by its argument round.  If the argument is not equal to the
       value of a rounding direction macro, the rounding direction is not
       changed.

RETURN VALUE
       The fegetround() function shall return the value of the rounding
       direction macro representing the current rounding direction or a
       negative value if there is no such rounding direction macro or the
       current rounding direction is not determinable.

       The fesetround() function shall return a zero value if and only if the
       requested rounding direction was established.

ERRORS
       No errors are defined.

       The following sections are informative.

EXAMPLES
       The following example saves, sets, and restores the rounding direction,
       reporting an error and aborting if setting the rounding direction
       fails:


           #include <fenv.h>
           #include <assert.h>
           void f(int round_dir)
           {
               #pragma STDC FENV_ACCESS ON
               int save_round;
               int setround_ok;
               save_round = fegetround();
               setround_ok = fesetround(round_dir);
               assert(setround_ok == 0);
               /* ... */
               fesetround(save_round);
               /* ... */
           }

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       The Base Definitions volume of POSIX.1-2017, <fenv.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  In the event of any discrepancy between this version and the
       original IEEE and The Open Group Standard, the original IEEE and The
       Open Group Standard is the referee document. The original Standard can
       be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                        FEGETROUND(3)
