nearbyint(), nearbyintf(), nearbyintl()

Updated: May 06, 2022

Return a rounded integer value

Synopsis:

#include <math.h>

double nearbyint( double x);

float nearbyintf( float x);

long double nearbyintl( long double x);

Arguments:

x
The number that you want to round.

Library:

libm
The general-purpose math library.
libm-sve
(QNX Neutrino 7.1 or later) A library that optimizes the code for ARMv8.2 chips that have Scalable Vector Extension hardware.

Your system requirements will determine how you should work with these libraries:

Note: Compile your program with the -fno-builtin option to prevent the compiler from using a built-in version of the function.

Description:

The nearbyint(), nearbyintf(), and nearbyintl() functions round their argument to an integer value in floating-point format, using the current rounding direction and without raising the inexact floating-point exception.

To check for error situations, use feclearexcept() and fetestexcept(). For example:

Returns:

The rounded integer value, with the same sign as x.

If x is: These functions return: Errors:
±0.0 ±0.0
±Inf x
NaN NaN

These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.

Classification:

C11, POSIX 1003.1

Safety:  
Cancellation point No
Interrupt handler Yes
Signal handler Yes
Thread Yes