1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
3 .\" %%%LICENSE_START(VERBATIM)
4 .\" Permission is granted to make and distribute verbatim copies of this
5 .\" manual provided the copyright notice and this permission notice are
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8 .\" Permission is granted to copy and distribute modified versions of this
9 .\" manual under the conditions for verbatim copying, provided that the
10 .\" entire resulting derived work is distributed under the terms of a
11 .\" permission notice identical to this one.
13 .\" Since the Linux kernel and libraries are constantly changing, this
14 .\" manual page may be incorrect or out-of-date. The author(s) assume no
15 .\" responsibility for errors or omissions, or for damages resulting from
16 .\" the use of the information contained herein. The author(s) may not
17 .\" have taken the same level of care in the production of this manual,
18 .\" which is licensed free of charge, as they might when working
21 .\" Formatted or processed versions of this manual, if unaccompanied by
22 .\" the source, must acknowledge the copyright and authors of this work.
25 .\" References consulted:
26 .\" Linux libc source code
27 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
29 .\" Modified Sat Jul 24 17:48:42 1993 by Rik Faith (faith@cs.unc.edu)
30 .TH TELLDIR 3 2013-09-02 "" "Linux Programmer's Manual"
32 telldir \- return current location in directory stream
35 .B #include <dirent.h>
37 .BI "long telldir(DIR *" dirp );
41 Feature Test Macro Requirements for glibc (see
42 .BR feature_test_macros (7)):
46 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE
50 function returns the current location associated with
51 the directory stream \fIdirp\fP.
55 function returns the current location
56 in the directory stream.
57 On error, \-1 is returned, and
63 Invalid directory stream descriptor \fIdirp\fP.
65 .SS Multithreading (see pthreads(7))
68 function is thread-safe.
72 In glibc up to version 2.1.1, the return type of
76 POSIX.1-2001 specifies
78 and this is the type used since glibc 2.1.2.
80 In early filesystems, the value returned by
82 was a simple file offset within a directory.
83 Modern filesystems use tree or hash structures, rather than flat tables,
84 to represent directories.
85 On such filesystems, the value returned by
87 (and used internally by
89 is a "cookie" that is used by the implementation
90 to derive a position within a directory.
91 .\" https://lwn.net/Articles/544298/
92 Application programs should treat this strictly as an opaque value, making
94 assumptions about its contents.