Added RETURN VALUE section.

[thirdparty/man-pages.git] / man3 / rint.3

.\" Copyright 2001 Andries Brouwer <aeb@cwi.nl>.
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.TH RINT 3  2007-07-26 "" "Linux Programmer's Manual"
.SH NAME
nearbyint, nearbyintf, nearbyintl, rint, rintf, rintl \- round to nearest integer
.SH SYNOPSIS
.nf
.B #include <math.h>
.sp
.BI "double nearbyint(double " x );
.br
.BI "float nearbyintf(float " x );
.br
.BI "long double nearbyintl(long double " x );
.sp
.BI "double rint(double " x );
.br
.BI "float rintf(float " x );
.br
.BI "long double rintl(long double " x );
.fi
.sp
Link with \fI\-lm\fP.
.sp
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.sp
.ad l
.BR nearbyint (),
.BR nearbyintf (),
.BR nearbyintl ():
_XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
.I cc\ -std=c99
.br
.BR rint (),
.BR rintf (),
.BR rintl ():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500 || _ISOC99_SOURCE; or
.I cc\ -std=c99
.ad b
.SH DESCRIPTION
The
.BR nearbyint ()
functions round their argument to an integer value in floating point
format, using the current rounding direction and without raising the
.I inexact
exception.
.LP
The
.BR rint ()
functions do the same, but will raise the
.I inexact
exception when the result differs in value from the argument.
.SH "RETURN VALUE"
The rounded integer value.
If \fIx\fP is integral or infinite,
\fIx\fP itself is returned.
.SH ERRORS
No errors other than
.B EDOM
and
.B ERANGE
can occur.
If \fIx\fP is NaN, then NaN is returned and
.I errno
may be set to
.BR EDOM .
.SH "CONFORMING TO"
C99.
.SH NOTES
SUSv2 and POSIX.1-2001 contain text about overflow (which might set
.I errno
to
.BR ERANGE ,
or raise an 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 128 (respectively, 1024), and the number
of mantissa bits is 24 (respectively, 53).)
.SH "SEE ALSO"
.BR ceil (3),
.BR floor (3),
.BR lrint (3),
.BR round (3),
.BR trunc (3)