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.
10

NAME

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

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

23       The  functionality described on this reference page is aligned with the
24       ISO C standard. Any conflict between the  requirements  described  here
25       and  the  ISO C  standard is unintentional. This volume of POSIX.1‐2017
26       defers to the ISO C standard.
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28       These functions shall round their argument to the nearest integer value
29       in  floating-point  format,  rounding  halfway  cases  away  from zero,
30       regardless of the current rounding direction.
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RETURN VALUE

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

41       No errors are defined.
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43       The following sections are informative.
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EXAMPLES

46       None.
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APPLICATION USAGE

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

58       None.
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FUTURE DIRECTIONS

61       None.
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SEE ALSO

64       feclearexcept(), fetestexcept()
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66       The Base Definitions volume of POSIX.1‐2017, Section 4.20, Treatment of
67       Error Conditions for Mathematical Functions, <math.h>
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70       Portions of this text are reprinted and reproduced in  electronic  form
71       from  IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
72       table Operating System Interface (POSIX), The Open Group Base  Specifi‐
73       cations  Issue  7, 2018 Edition, Copyright (C) 2018 by the Institute of
74       Electrical and Electronics Engineers, Inc and The Open Group.   In  the
75       event of any discrepancy between this version and the original IEEE and
76       The Open Group Standard, the original IEEE and The Open Group  Standard
77       is  the  referee document. The original Standard can be obtained online
78       at http://www.opengroup.org/unix/online.html .
79
80       Any typographical or formatting errors that appear  in  this  page  are
81       most likely to have been introduced during the conversion of the source
82       files to man page format. To report such errors,  see  https://www.ker‐
83       nel.org/doc/man-pages/reporting_bugs.html .
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87IEEE/The Open Group                  2017                            ROUND(3P)
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