.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
.\" <mtk.manpages@gmail.com>
.\"
+.\" %%%LICENSE_START(VERBATIM)
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
+.\" %%%LICENSE_END
.\"
-.TH RINT 3 2008-07-29 "" "Linux Programmer's Manual"
+.TH RINT 3 2017-09-15 "" "Linux Programmer's Manual"
.SH NAME
nearbyint, nearbyintf, nearbyintl, rint, rintf, rintl \- round
to nearest integer
.SH SYNOPSIS
.nf
.B #include <math.h>
-.sp
+.PP
.BI "double nearbyint(double " x );
-.br
.BI "float nearbyintf(float " x );
-.br
.BI "long double nearbyintl(long double " x );
-.sp
+.PP
.BI "double rint(double " x );
-.br
.BI "float rintf(float " x );
-.br
.BI "long double rintl(long double " x );
.fi
-.sp
+.PP
Link with \fI\-lm\fP.
-.sp
+.PP
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
-.sp
+.PP
.ad l
.BR nearbyint (),
.BR nearbyintf (),
.BR nearbyintl ():
-_XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
-.I cc\ -std=c99
+.RS 4
+_POSIX_C_SOURCE\ >=\ 200112L || _ISOC99_SOURCE
+.RE
.br
.BR rint ():
-_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500 || _ISOC99_SOURCE; or
-.I cc\ -std=c99
+.RS 4
+_ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
+ || _XOPEN_SOURCE\ >=\ 500
+.\" || _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
+ || /* Since glibc 2.19: */ _DEFAULT_SOURCE
+ || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
+.RE
.br
.BR rintf (),
.BR rintl ():
-_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
-.I cc\ -std=c99
+.RS 4
+_ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
+ || /* Since glibc 2.19: */ _DEFAULT_SOURCE
+ || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
+.RE
.ad b
.SH DESCRIPTION
The
-.BR nearbyint ()
+.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.
-.LP
+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 rint (),
+.BR rintf (),
+and
+.BR rintl ()
functions do the same, but will raise the
.I inexact
exception
checkable via
.BR fetestexcept (3))
when the result differs in value from the argument.
-.SH "RETURN VALUE"
+.SH RETURN VALUE
These functions return the rounded integer value.
-
-If \fIx\fP is integral, +0, \-0, NaN, or infinite,
-\fIx\fP itself is returned.
+.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 "CONFORMING TO"
-C99, POSIX.1-2001.
+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;
+lbw26 lb lb
+l l l.
+Interface Attribute Value
+T{
+.BR nearbyint (),
+.BR nearbyintf (),
+.br
+.BR nearbyintl (),
+.BR rint (),
+.br
+.BR rintf (),
+.BR rintl ()
+T} Thread safety MT-Safe
+.TE
+.SH CONFORMING TO
+C99, POSIX.1-2001, POSIX.1-2008.
.SH NOTES
SUSv2 and POSIX.1-2001 contain text about overflow (which might set
.I errno
For the IEEE-754 standard 32-bit and 64-bit floating-point numbers
the maximum value of the exponent is 128 (respectively, 1024),
and the number of mantissa bits 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"
+.SH SEE ALSO
.BR ceil (3),
.BR floor (3),
.BR lrint (3),
projects / thirdparty / man-pages.git / blobdiff