NAME

nearbyint, nearbyintf, nearbyintl — floating-point rounding functions

SYNOPSIS

#include <math.h>

double nearbyint(double x);
float nearbyintf(float x);
long double nearbyintl(long double x);


DESCRIPTION

^[CX] 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.1-2024 defers to the ISO C standard.

These functions shall round their argument to an integer value in floating-point format, using the current rounding direction and without raising the inexact floating-point exception.

RETURN VALUE

Upon successful completion, these functions shall return the rounded integer value. ^[MX]  The result shall have the same sign as x.

^[MX] If x is NaN, a NaN shall be returned.

If x is ±0, ±0 shall be returned.

If x is ±Inf, x shall be returned.

ERRORS

No errors are defined.

EXAMPLES

None.

APPLICATION USAGE

The integral value returned by these functions need not be expressible as an intmax_t. The return value should be tested before assigning it to an integer type to avoid the undefined results of an integer overflow.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

feclearexcept, fetestexcept

XBD 4.23 Treatment of Error Conditions for Mathematical Functions, <math.h>

CHANGE HISTORY

First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.

Issue 7

POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0402 [346,428] is applied.