lrint(3) Library Functions Manual lrint(3)

lrint, lrintf, lrintl, llrint, llrintf, llrintl - round to nearest integer

Math library (libm, -lm)

#include <math.h>
long lrint(double x);
long lrintf(float x);
long lrintl(long double x);
long long llrint(double x);
long long llrintf(float x);
long long llrintl(long double x);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

All functions shown above:


_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

These functions round their argument to the nearest integer value, using the current rounding direction (see fesetround(3)).

Note that unlike the rint(3) family of functions, the return type of these functions differs from that of their arguments.

These functions return the rounded integer value.

If x is a NaN or an infinity, or the rounded value is too large to be stored in a long (long long in the case of the ll* functions), then a domain error occurs, and the return value is unspecified.

See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:

An invalid floating-point exception (FE_INVALID) is raised.

These functions do not set errno.

For an explanation of the terms used in this section, see attributes(7).

Interface Attribute Value
lrint (), lrintf (), lrintl (), llrint (), llrintf (), llrintl () Thread safety MT-Safe

C11, POSIX.1-2008.

glibc 2.1. C99, POSIX.1-2001.

ceil(3), floor(3), lround(3), nearbyint(3), rint(3), round(3)

2023-10-31 Linux man-pages 6.06