получить и установить текущее направление округления (get and set current rounding direction)
Пролог (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.
Имя (Name)
fegetround, fesetround — get and set current rounding direction
Синопсис (Synopsis)
#include <fenv.h>
int fegetround(void);
int fesetround(int round);
Описание (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.
Возвращаемое значение (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.
Ошибки (Error)
No errors are defined.
The following sections are informative.
Примеры (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);
/* ... */
}
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
The Base Definitions volume of POSIX.1‐2017, fenv.h(0p)
