ffs(3) [xfree86 man page]

FFS(3)							     Linux Programmer's Manual							    FFS(3)

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);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       ffs():
	   Since glibc 2.12:
		   _XOPEN_SOURCE >= 700
		   || ! (_POSIX_C_SOURCE >= 200809L)
		   || /* Glibc since 2.19: */ _DEFAULT_SOURCE
		   || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
	   Before glibc 2.12:
	       none
       ffsl(), ffsll():
	   Since glibc 2.27:
		   _DEFAULT_SOURCE
	   Before glibc 2.27:
		   _GNU_SOURCE

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.

NOTES

       BSD systems have a prototype in <string.h>.

SEE ALSO

       memchr(3)

COLOPHON

       This  page is part of release 4.15 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/.

GNU
								    2017-09-15								    FFS(3)

Check Out this Related Man Page

SEEKDIR(3)                                                   Linux Programmer's Manual                                                  SEEKDIR(3)

NAME

       seekdir - set the position of the next readdir() call in the directory stream.

SYNOPSIS

       #include <dirent.h>

       void seekdir(DIR *dirp, long loc);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       seekdir():
        _XOPEN_SOURCE
           || /* Glibc since 2.19: */ _DEFAULT_SOURCE
           || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

       The  seekdir()  function sets the location in the directory stream from which the next readdir(2) call will start.  The loc argument should
       be a value returned by a previous call to telldir(3).

RETURN VALUE

       The seekdir() function returns no value.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       +----------+---------------+---------+
       |Interface | Attribute     | Value   |
       +----------+---------------+---------+
       |seekdir() | Thread safety | MT-Safe |
       +----------+---------------+---------+
CONFORMING TO

       POSIX.1-2001, POSIX.1-2008, 4.3BSD.

NOTES

       In glibc up to version 2.1.1, the type of the loc argument was off_t.  POSIX.1-2001 specifies long, and this is the type used  since  glibc
       2.1.2.  See telldir(3) for information on why you should be careful in making any assumptions about the value in this argument.

SEE ALSO

       lseek(2), closedir(3), opendir(3), readdir(3), rewinddir(3), scandir(3), telldir(3)

COLOPHON

       This  page is part of release 4.15 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/.

                                                                    2016-03-15                                                          SEEKDIR(3)

Linux and UNIX Man Pages

ffs(3) [xfree86 man page]

Check Out this Related Man Page