Originální popis anglicky:
seekdir - set the position of a directory stream
Návod, kniha: POSIX Programmer's Manual
#include <dirent.h>
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.
None.
None.
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.
None.
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 original
Standard can be obtained online at http://www.opengroup.org/unix/online.html
.
