1FLOOR(3P)                  POSIX Programmer's Manual                 FLOOR(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       floor, floorf, floorl — floor function
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SYNOPSIS

16       #include <math.h>
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18       double floor(double x);
19       float floorf(float x);
20       long double floorl(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.1‐2008
26       defers to the ISO C standard.
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28       These  functions  shall  compute the largest integral value not greater
29       than x.
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RETURN VALUE

32       The result shall have the same sign as x.
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34       Upon successful completion, these functions shall  return  the  largest
35       integral  value  not  greater  than x, expressed as a double, float, or
36       long double, as appropriate for the return type of the function.
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38       If x is NaN, a NaN shall be returned.
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40       If x is ±0 or ±Inf, x shall be returned.
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ERRORS

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

48       None.
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APPLICATION USAGE

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

60       None.
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FUTURE DIRECTIONS

63       None.
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SEE ALSO

66       ceil(), feclearexcept(), fetestexcept(), isnan()
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68       Section 4.19, Treatment of Error Conditions for Mathematical Functions,
69       <math.h>
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72       Portions  of  this text are reprinted and reproduced in electronic form
73       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
74       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
75       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
76       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
77       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  In  the
78       event of any discrepancy between this version and the original IEEE and
79       The Open Group Standard, the original IEEE and The Open Group  Standard
80       is  the  referee document. The original Standard can be obtained online
81       at http://www.unix.org/online.html .
82
83       Any typographical or formatting errors that appear  in  this  page  are
84       most likely to have been introduced during the conversion of the source
85       files to man page format. To report such errors,  see  https://www.ker‐
86       nel.org/doc/man-pages/reporting_bugs.html .
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90IEEE/The Open Group                  2013                            FLOOR(3P)
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