diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-24 04:52:22 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-24 04:52:22 +0000 |
commit | 3d08cd331c1adcf0d917392f7e527b3f00511748 (patch) | |
tree | 312f0d1e1632f48862f044b8bb87e602dcffb5f9 /man/man3/round.3 | |
parent | Adding debian version 6.7-2. (diff) | |
download | manpages-3d08cd331c1adcf0d917392f7e527b3f00511748.tar.xz manpages-3d08cd331c1adcf0d917392f7e527b3f00511748.zip |
Merging upstream version 6.8.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'man/man3/round.3')
-rw-r--r-- | man/man3/round.3 | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/man/man3/round.3 b/man/man3/round.3 new file mode 100644 index 0000000..86bc373 --- /dev/null +++ b/man/man3/round.3 @@ -0,0 +1,110 @@ +'\" t +.\" Copyright 2001 Andries Brouwer <aeb@cwi.nl>. +.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk +.\" <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH round 3 2024-05-02 "Linux man-pages (unreleased)" +.SH NAME +round, roundf, roundl \- round to nearest integer, away from zero +.SH LIBRARY +Math library +.RI ( libm ", " \-lm ) +.SH SYNOPSIS +.nf +.B #include <math.h> +.P +.BI "double round(double " x ); +.BI "float roundf(float " x ); +.BI "long double roundl(long double " x ); +.fi +.P +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.P +.BR round (), +.BR roundf (), +.BR roundl (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L +.fi +.SH DESCRIPTION +These functions round +.I x +to the nearest integer, but +round halfway cases away from zero (regardless of the current rounding +direction, see +.BR fenv (3)), +instead of to the nearest even integer like +.BR rint (3). +.P +For example, +.I round(0.5) +is 1.0, and +.I round(\-0.5) +is \-1.0. +.SH RETURN VALUE +These functions return the rounded integer value. +.P +If +.I x +is integral, +0, \-0, NaN, or infinite, +.I x +itself is returned. +.SH ERRORS +No errors occur. +POSIX.1-2001 documents a range error for overflows, but see NOTES. +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR round (), +.BR roundf (), +.BR roundl () +T} Thread safety MT-Safe +.TE +.SH STANDARDS +C11, POSIX.1-2008. +.SH HISTORY +glibc 2.1. +C99, POSIX.1-2001. +.SH NOTES +POSIX.1-2001 contains text about overflow (which might set +.I errno +to +.BR ERANGE , +or raise an +.B FE_OVERFLOW +exception). +In practice, the result cannot overflow on any current machine, +so this error-handling stuff is just nonsense. +.\" The POSIX.1-2001 APPLICATION USAGE SECTION discusses this point. +(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).) +.P +If you want to store the rounded value in an integer type, +you probably want to use one of the functions described in +.BR lround (3) +instead. +.SH SEE ALSO +.BR ceil (3), +.BR floor (3), +.BR lround (3), +.BR nearbyint (3), +.BR rint (3), +.BR trunc (3) |