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Diffstat (limited to 'man3/rint.3')
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diff --git a/man3/rint.3 b/man3/rint.3 new file mode 100644 index 0000000..945f48b --- /dev/null +++ b/man3/rint.3 @@ -0,0 +1,146 @@ +'\" 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 rint 3 2023-07-20 "Linux man-pages 6.05.01" +.SH NAME +nearbyint, nearbyintf, nearbyintl, rint, rintf, rintl \- round +to nearest integer +.SH LIBRARY +Math library +.RI ( libm ", " \-lm ) +.SH SYNOPSIS +.nf +.B #include <math.h> +.PP +.BI "double nearbyint(double " x ); +.BI "float nearbyintf(float " x ); +.BI "long double nearbyintl(long double " x ); +.PP +.BI "double rint(double " x ); +.BI "float rintf(float " x ); +.BI "long double rintl(long double " x ); +.fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.BR nearbyint (), +.BR nearbyintf (), +.BR nearbyintl (): +.nf + _POSIX_C_SOURCE >= 200112L || _ISOC99_SOURCE +.fi +.PP +.BR rint (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L + || _XOPEN_SOURCE >= 500 +.\" || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED + || /* Since glibc 2.19: */ _DEFAULT_SOURCE + || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE +.fi +.PP +.BR rintf (), +.BR rintl (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L + || /* Since glibc 2.19: */ _DEFAULT_SOURCE + || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE +.fi +.SH DESCRIPTION +The +.BR nearbyint (), +.BR nearbyintf (), +and +.BR nearbyintl () +functions round their argument to an integer value in floating-point +format, using the current rounding direction (see +.BR fesetround (3)) +and without raising the +.I inexact +exception. +When the current rounding direction is to nearest, these +functions round halfway cases to the even integer in accordance with +IEEE-754. +.PP +The +.BR rint (), +.BR rintf (), +and +.BR rintl () +functions do the same, but will raise the +.I inexact +exception +.RB ( FE_INEXACT , +checkable via +.BR fetestexcept (3)) +when the result differs in value from the argument. +.SH RETURN VALUE +These functions return the rounded integer value. +.PP +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 nearbyint (), +.BR nearbyintf (), +.BR nearbyintl (), +.BR rint (), +.BR rintf (), +.BR rintl () +T} Thread safety MT-Safe +.TE +.sp 1 +.SH STANDARDS +C11, POSIX.1-2008. +.SH HISTORY +C99, POSIX.1-2001. +.SH NOTES +SUSv2 and POSIX.1-2001 contain 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. +(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).) +.PP +If you want to store the rounded value in an integer type, +you probably want to use one of the functions described in +.BR lrint (3) +instead. +.SH SEE ALSO +.BR ceil (3), +.BR floor (3), +.BR lrint (3), +.BR round (3), +.BR trunc (3) |