1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
|
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
.TH "NEARBYINT" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" nearbyint
.SH NAME
nearbyint, nearbyintf, nearbyintl \- floating-point rounding functions
.SH SYNOPSIS
.LP
\fB#include <math.h>
.br
.sp
double nearbyint(double\fP \fIx\fP\fB);
.br
float nearbyintf(float\fP \fIx\fP\fB);
.br
long double nearbyintl(long double\fP \fIx\fP\fB);
.br
\fP
.SH DESCRIPTION
.LP
These functions shall round their argument to an integer value in
floating-point format, using the current rounding direction
and without raising the inexact floating-point exception.
.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 NaN shall be returned.
.LP
If \fIx\fP is \(+-0, \(+-0 shall be returned.
.LP
If \fIx\fP is \(+-Inf, \fIx\fP shall be returned.
.LP
If the correct value would cause overflow, a range error shall occur
and \fInearbyint\fP(), \fInearbyintf\fP(), and
\fInearbyintl\fP() shall return the value of the macro \(+-HUGE_VAL,
\(+-HUGE_VALF, and \(+-HUGE_VALL (with the same
sign as \fIx\fP), respectively.
.SH ERRORS
.LP
These functions shall fail if:
.TP 7
Range\ Error
The result would cause an overflow.
.LP
If the integer expression (math_errhandling & MATH_ERRNO) is non-zero,
then \fIerrno\fP shall be set to [ERANGE]. If the
integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero,
then the overflow 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
None.
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIfeclearexcept\fP() , \fIfetestexcept\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 .
|
