FFS(3) MachTen Programmer’s Manual FFS(3)

NAME
ffs - find first bit set in a bit string

SYNOPSIS
#include <string.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)

HISTORY
The ffs() function appeared in 4.3BSD.

4.4BSD April 19, 1994 1