Name
ffs — find first bit set in a word
Synopsis
int
ffsll( |
long long int |
i) ; |
DESCRIPTION
The ffs
() function returns
the position of the first (least significant) bit set in the
word i
. The least
significant bit is position 1 and the most significant
position is, for example, 32 or 64. The functions
ffsll
() and ffsl
() do the same but take arguments of
possibly different size.
RETURN VALUE
These functions return the position of the first bit set,
or 0 if no bits are set in i
.
CONFORMING TO
4.3BSD, POSIX.1-2001.
NOTES
BSD systems have a prototype in <string.h>
.
SEE ALSO
feature_test_macros(7)
Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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References consulted:
Linux libc source code
Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
386BSD man pages
Modified Sat Jul 24 19:39:35 1993 by Rik Faith (faith@cs.unc.edu)
Modified 2003 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
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