1SEEKDIR(P)                 POSIX Programmer's Manual                SEEKDIR(P)
2
3
4

NAME

6       seekdir - set the position of a directory stream
7

SYNOPSIS

9       #include <dirent.h>
10
11       void seekdir(DIR *dirp, long loc);
12
13

DESCRIPTION

15       The  seekdir()  function  shall  set the position of the next readdir()
16       operation on the directory stream specified by  dirp  to  the  position
17       specified  by  loc.  The value of loc should have been returned from an
18       earlier call to telldir(). The new position reverts to the one  associ‐
19       ated with the directory stream when telldir() was performed.
20
21       If the value of loc was not obtained from an earlier call to telldir(),
22       or if a call to rewinddir() occurred between the call to telldir()  and
23       the call to seekdir(), the results of subsequent calls to readdir() are
24       unspecified.
25

RETURN VALUE

27       The seekdir() function shall not return a value.
28

ERRORS

30       No errors are defined.
31
32       The following sections are informative.
33

EXAMPLES

35       None.
36

APPLICATION USAGE

38       None.
39

RATIONALE

41       The original standard developers perceived that there were restrictions
42       on  the  use of the seekdir() and telldir() functions related to imple‐
43       mentation details, and for that reason these functions need not be sup‐
44       ported  on all POSIX-conforming systems. They are required on implemen‐
45       tations supporting the XSI extension.
46
47       One of the perceived problems of implementation is that returning to  a
48       given  point in a directory is quite difficult to describe formally, in
49       spite of its intuitive appeal, when systems that use  B-trees,  hashing
50       functions,  or  other similar mechanisms to order their directories are
51       considered. The definition of seekdir() and telldir() does not  specify
52       whether,  when  using these interfaces, a given directory entry will be
53       seen at all, or more than once.
54
55       On systems not supporting these functions, their capability  can  some‐
56       times be accomplished by saving a filename found by readdir() and later
57       using rewinddir() and a loop on readdir() to relocate the position from
58       which the filename was saved.
59

FUTURE DIRECTIONS

61       None.
62

SEE ALSO

64       opendir()  ,  readdir()  ,  telldir()  , the Base Definitions volume of
65       IEEE Std 1003.1-2001, <dirent.h>, <stdio.h>, <sys/types.h>
66

68       Portions of this text are reprinted and reproduced in  electronic  form
69       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
70       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
71       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
72       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
73       event of any discrepancy between this version and the original IEEE and
74       The Open Group Standard, the original IEEE and The Open Group  Standard
75       is  the  referee document. The original Standard can be obtained online
76       at http://www.opengroup.org/unix/online.html .
77
78
79
80IEEE/The Open Group                  2003                           SEEKDIR(P)
Impressum