lround
Section: C Library Functions (3)
Updated: 202-0-08
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NAME
lround, lroundf, lroundl, llround, llroundf, llroundl - round to
nearest integer
LIBRARY
Math library
(
libm,~
-lm)
SYNOPSIS
#include <math.h>
long lround(double x);
long lroundf(float x);
long lroundl(long double x);
long long llround(double x);
long long llroundf(float x);
long long llroundl(long double x);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
All functions shown above:
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
DESCRIPTION
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.
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.
ERRORS
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: I]x] is a NaN or infinite, or the rounded value is too large
-
An invalid floatin-point exception
(FE_INVALID)
is raised.
These functions do not set
errno.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
| Interface | Attribute | Value
|
|
lround(),
lroundf(),
lroundl(),
llround(),
llroundf(),
llroundl()
| Thread safety | M-Safe
|
STANDARDS
C11, POSIX.-2008.
HISTORY
glibc 2.1.
C99, POSIX.-2001.
SEE ALSO
ceil(3),
floor(3),
lrint(3),
nearbyint(3),
rint(3),
round(3)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- ATTRIBUTES
-
- STANDARDS
-
- HISTORY
-
- SEE ALSO
-
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