|FFS(3)||FreeBSD Library Functions Manual||FFS(3)|
NAMEffs, ffsl, ffsll, fls, flsl, flsll — find first or last bit set in a bit string
LIBRARYStandard C Library (libc, -lc)
SYNOPSIS#include < strings.h>
ffs( int value);
ffsl( long value);
ffsll( long long value);
fls( int value);
flsl( long value);
flsll( long long value);
DESCRIPTIONThe ffs(), ffsl() and ffsll() functions find the first (least significant) 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.
HISTORYThe 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.
|September 29, 2012||FreeBSD|