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seekdir(3p) [centos man page]

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

PROLOG

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

NAME

       seekdir - set the position of a directory stream

SYNOPSIS

       #include <dirent.h>

       void seekdir(DIR *dirp, long loc);

DESCRIPTION

       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 associ-
       ated 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

       The seekdir() function shall not return a value.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       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 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.

FUTURE DIRECTIONS

       None.

SEE ALSO

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

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- 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 original Standard can  be  obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003							       SEEKDIR(3P)

Check Out this Related Man Page

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

PROLOG

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

NAME

       rewinddir - reset the position of a directory stream to the beginning of a directory

SYNOPSIS

       #include <dirent.h>

       void rewinddir(DIR *dirp);

DESCRIPTION

       The rewinddir() function shall reset the position of the directory stream to which dirp refers to the beginning of the directory. It  shall
       also  cause  the  directory stream to refer to the current state of the corresponding directory, as a call to opendir() would have done. If
       dirp does not refer to a directory stream, the effect is undefined.

       After a call to the fork() function, either the parent or child (but not both) may continue processing the  directory  stream  using  read-
       dir(), rewinddir(), or seekdir().  If both the parent and child processes use these functions, the result is undefined.

RETURN VALUE

       The rewinddir() function shall not return a value.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The  rewinddir() function should be used in conjunction with opendir(), readdir(), and closedir() to examine the contents of the directory.
       This method is recommended for portability.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       closedir(), opendir(), readdir(), the Base Definitions volume of IEEE Std 1003.1-2001, <dirent.h> <sys/types.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- 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 original Standard can be obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003							     REWINDDIR(3P)
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