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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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rint(3) Library Functions Manual rint(3)
nearbyint, nearbyintf, nearbyintl, rint, rintf, rintl - round to
nearest integer
Math library (libm, -lm)
#include <math.h>
double nearbyint(double x);
float nearbyintf(float x);
long double nearbyintl(long double x);
double rint(double x);
float rintf(float x);
long double rintl(long double x);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
nearbyint(), nearbyintf(), nearbyintl():
_POSIX_C_SOURCE >= 200112L || _ISOC99_SOURCE
rint():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| _XOPEN_SOURCE >= 500
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
rintf(), rintl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
The nearbyint(), nearbyintf(), and nearbyintl() functions round
their argument to an integer value in floating-point format,
using the current rounding direction (see fesetround(3)) and
without raising the inexact exception. When the current rounding
direction is to nearest, these functions round halfway cases to
the even integer in accordance with IEEE-754.
The rint(), rintf(), and rintl() functions do the same, but will
raise the inexact exception (FE_INEXACT, checkable via
fetestexcept(3)) when the result differs in value from the
argument.
These functions return the rounded integer value.
If x is integral, +0, -0, NaN, or infinite, x itself is returned.
No errors occur.
For an explanation of the terms used in this section, see
attributes(7).
┌─────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├─────────────────────────────────────┼───────────────┼─────────┤
│ nearbyint(), nearbyintf(), │ Thread safety │ MT-Safe │
│ nearbyintl(), rint(), rintf(), │ │ │
│ rintl() │ │ │
└─────────────────────────────────────┴───────────────┴─────────┘
C11, POSIX.1-2008.
C99, POSIX.1-2001.
SUSv2 and POSIX.1-2001 contain text about overflow (which might
set errno to ERANGE, or raise an FE_OVERFLOW exception). In
practice, the result cannot overflow on any current machine, so
this error-handling stuff was just nonsense. (More precisely,
overflow can happen only when the maximum value of the exponent
is smaller than the number of mantissa bits. For the IEEE-754
standard 32-bit and 64-bit floating-point numbers the maximum
value of the exponent is 127 (respectively, 1023), and the number
of mantissa bits including the implicit bit is 24 (respectively,
53).) This was removed in POSIX.1-2008.
If you want to store the rounded value in an integer type, you
probably want to use one of the functions described in lrint(3)
instead.
ceil(3), floor(3), lrint(3), round(3), trunc(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 2024-06-16 rint(3)
Pages that refer to this page: abs(3), ceil(3), fabs(3), floor(3), lrint(3), lround(3), nextafter(3), nextup(3), round(3), roundup(3), trunc(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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