seekdir(3p) — Linux manual page


SEEKDIR(3P)               POSIX Programmer's Manual              SEEKDIR(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior), or
       the interface may not be implemented on Linux.

NAME         top

       seekdir — set the position of a directory stream

SYNOPSIS         top

       #include <dirent.h>

       void seekdir(DIR *dirp, long loc);

DESCRIPTION         top

       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() using the same directory stream. 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.

RETURN VALUE         top

       The seekdir() function shall not return a value.

ERRORS         top

       No errors are defined.

       The following sections are informative.

EXAMPLES         top




RATIONALE         top

       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 option.

       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 than once.

       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 readdir() to relocate the
       position from which the filename was saved.



SEE ALSO         top

       fdopendir(3p), readdir(3p), telldir(3p)

       The Base Definitions volume of POSIX.1‐2008, dirent.h(0p),

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) 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 original
       Standard can be obtained online at .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see .

IEEE/The Open Group                 2013                         SEEKDIR(3P)

Pages that refer to this page: dirent.h(0p)telldir(3p)