ffs(3) [netbsd man page]

FFS(3)							   BSD Library Functions Manual 						    FFS(3)

NAME

     ffs -- find first bit set in a bit string

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <strings.h>

     int
     ffs(int value);

DESCRIPTION

     The ffs() function finds the first bit set in value and returns the index of that bit.  Bits are numbered starting from 1, starting at the
     right-most bit.  A return value of 0 means that the argument was zero.

SEE ALSO

     bitstring(3), ffs32(3), popcount(3)

STANDARDS

     The ffs() function conforms to IEEE Std 1003.1-2001 (``POSIX.1'').

HISTORY

     The ffs() function appeared in 4.3BSD.  The prototype for it existed previously in the <string.h> header before it was moved to <strings.h>
     for POSIX compliance.

BSD
								  April 28, 2010							       BSD

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

PROLOG

       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME

       ffs - find first set bit

SYNOPSIS

       #include <strings.h>

       int ffs(int i);

DESCRIPTION

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

RETURN VALUE

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

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       The Base Definitions volume of IEEE Std 1003.1-2001, <strings.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- 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 .

IEEE
/The Open Group						       2003								   FFS(3P)