Name
ffs, ffsl, ffsll — find first bit set in a word
Synopsis
#include <strings.h>
int
ffs( |
int i); |
#include <string.h>
int
ffsl( |
long int i); |
int
ffsll( |
long long int i); |
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Note | |||||||||
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DESCRIPTION
The ffs() function returns
the position of the first (least significant) bit set in the
word i. The least
significant bit is position 1 and the most significant
position is, for example, 32 or 64. The functions
ffsll() and ffsl() do the same but take arguments of
possibly different size.
RETURN VALUE
These functions return the position of the first bit set,
or 0 if no bits are set in i.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
ffs(), ffsl(), ffsll() |
Thread safety | MT-Safe |
CONFORMING TO
ffs(): POSIX.1-2001,
POSIX.1-2008, 4.3BSD.
The ffsl() and ffsll() functions are glibc extensions.
COLOPHON
This page is part of release 4.07 of the Linux man-pages project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
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Copyright 1993 David Metcalfe (davidprism.demon.co.uk) %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END References consulted: Linux libc source code Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) 386BSD man pages Modified Sat Jul 24 19:39:35 1993 by Rik Faith (faithcs.unc.edu) Modified 2003 Walter Harms (walter.harmsinformatik.uni-oldenburg.de) |