rint.3   [plain text]


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.\"     from: @(#)rint.3	5.1 (Berkeley) 5/2/91
.\"	$Id: rint.3,v 1.4 2004/12/20 21:35:46 scp Exp $
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.Dd January 23, 2003
.Dt RINT 3
.Os
.Sh NAME
.Nm rint ,
.Nm lrint ,
.Nm llrint
.Nd round to integral value
.Sh SYNOPSIS
.Fd #include <math.h>
.Ft double
.Fn rint "double x"
.Ft long double
.Fn rintl "long double x"
.Ft float
.Fn rintf "float x"
.Ft long int
.Fn lrint "double x"
.Ft long int
.Fn lrintl "long double x"
.Ft long int
.Fn lrintf "float x"
.Ft long long int
.Fn llrint "double x"
.Ft long long int
.Fn llrintl "long double x"
.Ft long long int
.Fn llrintf "float x"
.Sh DESCRIPTION
The
.Fn rint
functions return the integral value
nearest to
.Fa x
(according to the prevailing rounding mode) in floating-point format.
.Pp
The
.Fn lrint
and
.Fn llrint
functions return the integral value nearest to 
.Fa x
(according to the prevailing rounding mode) in the return formats specified.  If the rounded
value is outside the range of the return type, the numeric result is unspecified and the
"invalid" floating-point exception is raised. A range error may occur if the magnitude of 
.Fa x 
is too large. 
.Sh SPECIAL VALUES
.Fn rint "±0"
returns ±0 for all rounding modes.
.Pp
.Fn rint "±infinity"
returns ±infinity for all rounding modes.
.Pp
All these functions raise the "inexact" floating-point exception if the result differs in 
value from the argument (except when they raise some other floating-point exception, such as "invalid").
.Sh SEE ALSO
.Xr abs 3 ,
.Xr fabs 3 ,
.Xr ceil 3 ,
.Xr floor 3 ,
.Xr math 3
.Sh STANDARDS
The
.Fn rint
, 
.Fn lrint
, and
.Fn llrint
functions conform to ISO/IEC 9899:1999(E).