FFS(9) Basic C Library Functions FFS(9)

NAME ffs - find first set bit in word

SYNOPSIS int ffs(int x);

ARGUMENTS x the word to search

DESCRIPTION This is defined the same way as the libc and compiler builtin ffs routines, therefore differs in spirit from the other bitops.

ffs(value) returns 0 if value is 0 or the position of the first set bit if value is nonzero. The first (least significant) bit is at position 1.

COPYRIGHT Kernel Hackers Manual 2.6. January 2013 FFS(9)