lrint - Man Page

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.

Return Value

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:

Domain error: x is a NaN or infinite, or the rounded value is too large

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).

lrint(), lrintf(), lrintl(), llrint(), llrintf(), llrintl()Thread safetyMT-Safe


C11, POSIX.1-2008.


glibc 2.1. C99, POSIX.1-2001.

See Also

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

Referenced By

ceil(3), floor(3), lround(3), rint(3), roundup(3), trunc(3).

The man pages llrint(3), llrintf(3), llrintl(3), lrintf(3) and lrintl(3) are aliases of lrint(3).

2023-10-31 Linux man-pages 6.7