SEEKDIR(P) POSIX Programmer's Manual SEEKDIR(P)
seekdir - set the position of a directory stream
void seekdir(DIR *dirp, long loc);
The seekdir() function shall set the position of the next readdir() operation on the
directory stream specified by dirp to the position specified by loc. The value of loc
should have been returned from an earlier call to telldir(). The new position reverts to
the one associated with the directory stream when telldir() was performed.
If the value of loc was not obtained from an earlier call to telldir(), or if a call to
rewinddir() occurred between the call to telldir() and the call to seekdir(), the results
of subsequent calls to readdir() are unspecified.
The seekdir() function shall not return a value.
No errors are defined.
The following sections are informative.
The original standard developers perceived that there were restrictions on the use of the
seekdir() and telldir() functions related to implementation details, and for that reason
these functions need not be supported on all POSIX-conforming systems. They are required
on implementations supporting the XSI extension.
One of the perceived problems of implementation is that returning to a given point in a
directory is quite difficult to describe formally, in spite of its intuitive appeal, when
systems that use B-trees, hashing functions, or other similar mechanisms to order their
directories are considered. The definition of seekdir() and telldir() does not specify
whether, when using these interfaces, a given directory entry will be seen at all, or more
On systems not supporting these functions, their capability can sometimes be accomplished
by saving a filename found by readdir() and later using rewinddir() and a loop on read-
dir() to relocate the position from which the filename was saved.
opendir() , readdir() , telldir() , the Base Definitions volume of IEEE Std 1003.1-2001,
<dirent.h>, <stdio.h>, <sys/types.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std
1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and The Open Group
Standard, the original IEEE and The Open Group Standard is the referee document. The orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 SEEKDIR(P)