fegetround man page


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.

fegetround, fesetround — get and set current rounding direction


#include <fenv.h>

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


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.


No errors are defined.

The following sections are informative.


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)
    int save_round;
    int setround_ok;
    save_round = fegetround();
    setround_ok = fesetround(round_dir);
    assert(setround_ok == 0);
    /* ... */
    /* ... */

See Also

The Base Definitions volume of POSIX.1‐2008, <fenv.h>