.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 
.TH "LRINT" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" lrint 
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.SH NAME
lrint, lrintf, lrintl \- round to nearest integer value using current
rounding direction
.SH SYNOPSIS
.LP
\fB#include <math.h>
.br
.sp
long lrint(double\fP \fIx\fP\fB);
.br
long lrintf(float\fP \fIx\fP\fB);
.br
long lrintl(long double\fP \fIx\fP\fB);
.br
\fP
.SH DESCRIPTION
.LP
These functions shall round their argument to the nearest integer
value, rounding according to the current rounding
direction.
.LP
An application wishing to check for error situations should set \fIerrno\fP
to zero and call
\fIfeclearexcept\fP(FE_ALL_EXCEPT) before calling these functions.
On return, if \fIerrno\fP is non-zero or
\fIfetestexcept\fP(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW)
is non-zero, an error has occurred.
.SH RETURN VALUE
.LP
Upon successful completion, these functions shall return the rounded
integer value.
.LP
If
\fIx\fP is NaN, a domain error shall occur and an unspecified value
is returned.
.LP
If \fIx\fP is +Inf, a domain error shall occur and an unspecified
value is returned.
.LP
If \fIx\fP is -Inf, a domain error shall occur and an unspecified
value is returned.
.LP
If the correct value is positive and too large to represent as a \fBlong\fP,
a domain error shall occur and an unspecified
value is returned.
.LP
If the correct value is negative and too large to represent as a \fBlong\fP,
a domain error shall occur and an unspecified
value is returned. 
.SH ERRORS
.LP
These functions shall fail if:
.TP 7
Domain\ Error
The \fIx\fP argument is NaN or \(+-Inf, or the correct value is not
representable as an integer. 
.LP
If the integer expression (math_errhandling & MATH_ERRNO) is non-zero,
then \fIerrno\fP shall be set to [EDOM]. If the
integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero,
then the invalid floating-point exception shall be raised.
.sp
.LP
\fIThe following sections are informative.\fP
.SH EXAMPLES
.LP
None.
.SH APPLICATION USAGE
.LP
On error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling
& MATH_ERREXCEPT) are independent of
each other, but at least one of them must be non-zero.
.SH RATIONALE
.LP
These functions provide floating-to-integer conversions. They round
according to the current rounding direction. 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. When they raise no other floating-point exception and the
result differs from the argument, they raise the inexact
floating-point exception.
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIfeclearexcept\fP(), \fIfetestexcept\fP(), \fIllrint\fP(), the
Base Definitions volume of IEEE\ Std\ 1003.1-2001, Section 4.18, Treatment
of Error Conditions for Mathematical Functions, \fI<math.h>\fP
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .