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+'\" 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 2024-05-02 "Linux man-pages (unreleased)"
+.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>
+.P
+.BI "double nearbyint(double " x );
+.BI "float nearbyintf(float " x );
+.BI "long double nearbyintl(long double " x );
+.P
+.BI "double rint(double " x );
+.BI "float rintf(float " x );
+.BI "long double rintl(long double " x );
+.fi
+.P
+.RS -4
+Feature Test Macro Requirements for glibc (see
+.BR feature_test_macros (7)):
+.RE
+.P
+.BR nearbyint (),
+.BR nearbyintf (),
+.BR nearbyintl ():
+.nf
+ _POSIX_C_SOURCE >= 200112L || _ISOC99_SOURCE
+.fi
+.P
+.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
+.P
+.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.
+.P
+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.
+.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 nearbyint (),
+.BR nearbyintf (),
+.BR nearbyintl (),
+.BR rint (),
+.BR rintf (),
+.BR rintl ()
+T} Thread safety MT-Safe
+.TE
+.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).)
+.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 lrint (3)
+instead.
+.SH SEE ALSO
+.BR ceil (3),
+.BR floor (3),
+.BR lrint (3),
+.BR round (3),
+.BR trunc (3)