1FFS(3P)                    POSIX Programmer's Manual                   FFS(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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NAME

13       ffs — find first set bit
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SYNOPSIS

16       #include <strings.h>
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18       int ffs(int i);
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DESCRIPTION

21       The ffs() function shall find the first bit  set  (beginning  with  the
22       least significant bit) in i, and return the index of that bit. Bits are
23       numbered starting at one (the least significant bit).
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RETURN VALUE

26       The ffs() function shall return the index of the first bit set. If i is
27       0, then ffs() shall return 0.
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ERRORS

30       No errors are defined.
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32       The following sections are informative.
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EXAMPLES

35       None.
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APPLICATION USAGE

38       None.
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RATIONALE

41       None.
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FUTURE DIRECTIONS

44       None.
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SEE ALSO

47       The Base Definitions volume of POSIX.1‐2008, <strings.h>
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50       Portions  of  this text are reprinted and reproduced in electronic form
51       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
52       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
53       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
54       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
55       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  In  the
56       event of any discrepancy between this version and the original IEEE and
57       The Open Group Standard, the original IEEE and The Open Group  Standard
58       is  the  referee document. The original Standard can be obtained online
59       at http://www.unix.org/online.html .
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61       Any typographical or formatting errors that appear  in  this  page  are
62       most likely to have been introduced during the conversion of the source
63       files to man page format. To report such errors,  see  https://www.ker‐
64       nel.org/doc/man-pages/reporting_bugs.html .
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68IEEE/The Open Group                  2013                              FFS(3P)
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