lround, lroundf, lroundl, llround, llroundf, llroundl - round to nearest integer
#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:
_ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L
These functions round their argument to the nearest integer value, rounding
halfway cases away from zero, regardless of the current rounding direction
(see
fenv(3)).
Note that unlike the
round(3) and
ceil(3), 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:
- 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.
For an explanation of the terms used in this section, see
attributes(7).
Interface |
Attribute |
Value |
lround (), lroundf (), lroundl (), llround (), llroundf (), llroundl
() |
Thread safety |
MT-Safe |
C99, POSIX.1-2001, POSIX.1-2008.
ceil(3),
floor(3),
lrint(3),
nearbyint(3),
rint(3),
round(3)