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)

May 21, 2015 FFS(3C)