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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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lround(3) Library Functions Manual lround(3)
lround, lroundf, lroundl, llround, llroundf, llroundl - round to
nearest integer
Math library (libm, -lm)
#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
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.
For an explanation of the terms used in this section, see
attributes(7).
┌─────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├─────────────────────────────────────┼───────────────┼─────────┤
│ lround(), lroundf(), lroundl(), │ Thread safety │ MT-Safe │
│ llround(), llroundf(), llroundl() │ │ │
└─────────────────────────────────────┴───────────────┴─────────┘
C11, POSIX.1-2008.
glibc 2.1. C99, POSIX.1-2001.
ceil(3), floor(3), lrint(3), nearbyint(3), rint(3), round(3)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
[email protected]
Linux man-pages 6.9.1 2024-05-02 lround(3)
Pages that refer to this page: lrint(3), round(3), roundup(3)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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