manpagez: man pages & more
man ffs(3)
Home | html | info | man
ffs(3)                   BSD Library Functions Manual                   ffs(3)


NAME

     ffs, ffsl, ffsll, fls, flsl, flsll -- find first or last bit set in a bit
     string


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <strings.h>

     int
     ffs(int value);

     int
     ffsl(long value);

     int
     ffsll(long long value);

     int
     fls(int value);

     int
     flsl(long value);

     int
     flsll(long long value);


DESCRIPTION

     The ffs(), ffsl() and ffsll() functions find the first (least signifi-
     cant) bit set in value and return the index of that bit.

     The fls(), flsl() and flsll() functions find the last (most significant)
     bit set in value and return the index of that bit.

     Bits are numbered starting at 1, the least significant bit.  A return
     value of zero from any of these functions means that the argument was
     zero.


SEE ALSO

     bitstring(3)


HISTORY

     The ffs() function appeared in 4.3BSD.  Its prototype existed previously
     in <string.h> before it was moved to <strings.h> for IEEE Std 1003.1-2001
     (``POSIX.1'') compliance.

     The ffsl(), fls() and flsl() functions appeared in FreeBSD 5.3.  The
     ffsll() and flsll() functions appeared in FreeBSD 7.1.

BSD                           September 29, 2012                           BSD

Mac OS X 10.9.1 - Generated Tue Jan 7 19:41:40 CST 2014
© manpagez.com 2000-2017
Individual documents may contain additional copyright information.