NAME
ffs —
find first bit set in a bit
string
LIBRARY
library “libc”
SYNOPSIS
#include
<strings.h>
int
ffs(int
value);
DESCRIPTION
Theffs()
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
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.