fegetround(3p) — Linux manual page

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

PROLOG         top

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

NAME         top

       fegetround, fesetround — get and set current rounding direction

SYNOPSIS         top

       #include <fenv.h>

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

DESCRIPTION         top

       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         top

       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         top

       No errors are defined.

       The following sections are informative.

EXAMPLES         top

       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         top

       None.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       The Base Definitions volume of POSIX.1‐2017, fenv.h(0p)

COPYRIGHT         top

       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(3P)

Pages that refer to this page: fenv.h(0p),  fesetround(3p)

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