FFS(3C) Standard C Library Functions FFS(3C)

NAME


ffs - find first set bit

SYNOPSIS


#include <strings.h>

int ffs(int i);

int ffsl(long i);

int ffsll(long long i);

int fls(int i);

int flsl(long i);

int flsll(long long i);


DESCRIPTION


The ffs(), ffsl(), and ffsll() functions finds the first bit set
(beginning with the least significant bit) and return the index of that
bit. Bits are numbered starting at one (the least significant bit).


The fls(), flsl(), and flsll() functions find the last bit set (beginning
with the least significant bit) and return the index of that bit. Bits
are numbered starting at one (the least significant bit).

RETURN VALUES


The ffs(), ffsl(), and ffsll() functions returns the index of the first
bit set. If i is 0, then they return 0.


The fls(), flsl(), and flsll() functions return the index of the last bit
set. If i is 0, then they return 0.

ERRORS


No errors are defined.

ATTRIBUTES


See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Committed |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO


attributes(7), standards(7)

illumos May 21, 2015 FFS(3C)