NAME

fegetround, fesetround — control floating-point rounding direction modes

SYNOPSIS

Math Library (libm, -lm)
#include <fenv.h>

int
fegetround(void);

int
fesetround(int round);

DESCRIPTION

These functions provide control of floating-point rounding direction modes. The round input argument is a value specifying a rounding direction mode and containing any of the values listed below.

FE_TONEAREST

Results are rounded to the closest representable value. If the exact result is exactly half way between two representable values, the value whose last binary digit is even (zero) is chosen. This is the default mode.

FE_DOWNWARD

Results are rounded towards negative infinity.

FE_UPWARD

Results are rounded towards positive infinity.

FE_TOWARDZERO

Results are rounded towards zero.

The fegetround() function gets the current rounding direction.

The fesetround() function establishes the rounding direction represented by round. If the argument is not equal to the value of a rounding direction macro, the rounding direction is not changed.

RETURN VALUES

The fegetround() function returns the current rounding direction. The fesetround() function return zero on success, and non-zero if an error occurred.

SEE ALSO

feclearexcept(3), feenableexcept(3), fegetenv(3)

STANDARDS

The fegetround() and fesetround() functions conform to ISO/IEC 9899:1999 (“ISO C99”).

HISTORY

These functions first appeared in OpenBSD 5.0.