Round to nearest integer, away from zero
#include <math.h> long int lround(double x); long int lroundf(float x); long int lroundl(long double x); long long int llround(double x); long long int llroundf(float x); long long int llroundl(long double x);
Link with -lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
All functions shown above:
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
or cc -std=c99
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.
These functions first appeared in glibc in version 2.1.
The lround(), lroundf(), lroundl(), llround(), llroundf(), and llroundl() functions are thread-safe.
C99, POSIX.1-2001.
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