1ROUND(3P)                  POSIX Programmer's Manual                 ROUND(3P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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11

NAME

13       round, roundf, roundl — round to the nearest integer value in a  float‐
14       ing-point format
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SYNOPSIS

17       #include <math.h>
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19       double round(double x);
20       float roundf(float x);
21       long double roundl(long double x);
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DESCRIPTION

24       The  functionality described on this reference page is aligned with the
25       ISO C standard. Any conflict between the  requirements  described  here
26       and  the  ISO C  standard is unintentional. This volume of POSIX.1‐2008
27       defers to the ISO C standard.
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29       These functions shall round their argument to the nearest integer value
30       in  floating-point  format,  rounding  halfway  cases  away  from zero,
31       regardless of the current rounding direction.
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RETURN VALUE

34       Upon successful completion, these functions shall  return  the  rounded
35       integer value.  The result shall have the same sign as x.
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37       If x is NaN, a NaN shall be returned.
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39       If x is ±0 or ±Inf, x shall be returned.
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ERRORS

42       No errors are defined.
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44       The following sections are informative.
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EXAMPLES

47       None.
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APPLICATION USAGE

50       The  integral value returned by these functions need not be expressible
51       as an intmax_t.  The return value should be tested before assigning  it
52       to  an  integer type to avoid the undefined results of an integer over‐
53       flow.
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55       These functions may raise the inexact floating-point exception  if  the
56       result differs in value from the argument.
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RATIONALE

59       None.
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FUTURE DIRECTIONS

62       None.
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SEE ALSO

65       feclearexcept(), fetestexcept()
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67       The Base Definitions volume of POSIX.1‐2008, Section 4.19, Treatment of
68       Error Conditions for Mathematical Functions, <math.h>
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71       Portions of this text are reprinted and reproduced in  electronic  form
72       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
73       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
74       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
75       cal and Electronics Engineers,  Inc  and  The  Open  Group.   (This  is
76       POSIX.1-2008  with  the  2013  Technical Corrigendum 1 applied.) In the
77       event of any discrepancy between this version and the original IEEE and
78       The  Open Group Standard, the original IEEE and The Open Group Standard
79       is the referee document. The original Standard can be  obtained  online
80       at http://www.unix.org/online.html .
81
82       Any  typographical  or  formatting  errors that appear in this page are
83       most likely to have been introduced during the conversion of the source
84       files  to  man page format. To report such errors, see https://www.ker‐
85       nel.org/doc/man-pages/reporting_bugs.html .
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89IEEE/The Open Group                  2013                            ROUND(3P)
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