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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>
COPYRIGHT
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 .
IEEE/The Open Group 2013 FEGETROUND(3POSIX)