bionic (3) fegetround.3posix.gz

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PROLOG
       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
       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.1‐2008 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.1‐2008, <fenv.h>


       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications  Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
       and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/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 .