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1 | .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
2 | .\" | |
93015253 | 3 | .\" %%%LICENSE_START(VERBATIM) |
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4 | .\" Permission is granted to make and distribute verbatim copies of this |
5 | .\" manual provided the copyright notice and this permission notice are | |
6 | .\" preserved on all copies. | |
7 | .\" | |
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. | |
c13182ef | 12 | .\" |
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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14 | .\" manual page may be incorrect or out-of-date.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 | |
19 | .\" professionally. | |
c13182ef | 20 | .\" |
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21 | .\" Formatted or processed versions of this manual, if unaccompanied by |
22 | .\" the source, must acknowledge the copyright and authors of this work. | |
4b72fb64 | 23 | .\" %%%LICENSE_END |
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24 | .\" |
25 | .\" References consulted: | |
26 | .\" Linux libc source code | |
27 | .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) | |
28 | .\" 386BSD man pages | |
29 | .\" Modified Sat Jul 24 17:48:42 1993 by Rik Faith (faith@cs.unc.edu) | |
4b8c67d9 | 30 | .TH TELLDIR 3 2017-09-15 "" "Linux Programmer's Manual" |
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31 | .SH NAME |
32 | telldir \- return current location in directory stream | |
33 | .SH SYNOPSIS | |
34 | .nf | |
35 | .B #include <dirent.h> | |
68e4db0a | 36 | .PP |
48e39fa7 | 37 | .BI "long telldir(DIR *" dirp ); |
fea681da | 38 | .fi |
68e4db0a | 39 | .PP |
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40 | .in -4n |
41 | Feature Test Macro Requirements for glibc (see | |
42 | .BR feature_test_macros (7)): | |
43 | .in | |
68e4db0a | 44 | .PP |
cc4615cc | 45 | .BR telldir (): |
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46 | _XOPEN_SOURCE |
47 | || /* Glibc since 2.19: */ _DEFAULT_SOURCE | |
48 | || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE | |
fea681da | 49 | .SH DESCRIPTION |
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50 | The |
51 | .BR telldir () | |
52 | function returns the current location associated with | |
6dea120e | 53 | the directory stream \fIdirp\fP. |
47297adb | 54 | .SH RETURN VALUE |
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55 | On success, the |
56 | .BR telldir () | |
57 | function returns the current location | |
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58 | in the directory stream. |
59 | On error, \-1 is returned, and | |
60 | .I errno | |
61 | is set appropriately. | |
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62 | .SH ERRORS |
63 | .TP | |
64 | .B EBADF | |
6dea120e | 65 | Invalid directory stream descriptor \fIdirp\fP. |
f7dbb1ea | 66 | .SH ATTRIBUTES |
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67 | For an explanation of the terms used in this section, see |
68 | .BR attributes (7). | |
69 | .TS | |
70 | allbox; | |
71 | lb lb lb | |
72 | l l l. | |
73 | Interface Attribute Value | |
74 | T{ | |
f7dbb1ea | 75 | .BR telldir () |
a257b544 PH |
76 | T} Thread safety MT-Safe |
77 | .TE | |
47297adb | 78 | .SH CONFORMING TO |
12c3c485 | 79 | POSIX.1-2001, POSIX.1-2008, 4.3BSD. |
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80 | .SH NOTES |
81 | In glibc up to version 2.1.1, the return type of | |
82 | .BR telldir () | |
83 | was | |
84 | .IR off_t . | |
85 | POSIX.1-2001 specifies | |
86 | .IR long , | |
87 | and this is the type used since glibc 2.1.2. | |
847e0d88 | 88 | .PP |
9ee4a2b6 | 89 | In early filesystems, the value returned by |
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90 | .BR telldir () |
91 | was a simple file offset within a directory. | |
9ee4a2b6 | 92 | Modern filesystems use tree or hash structures, rather than flat tables, |
73f4bf1e | 93 | to represent directories. |
9ee4a2b6 | 94 | On such filesystems, the value returned by |
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95 | .BR telldir () |
96 | (and used internally by | |
97 | .BR readdir (3)) | |
98 | is a "cookie" that is used by the implementation | |
99 | to derive a position within a directory. | |
100 | .\" https://lwn.net/Articles/544298/ | |
101 | Application programs should treat this strictly as an opaque value, making | |
102 | .I no | |
103 | assumptions about its contents. | |
47297adb | 104 | .SH SEE ALSO |
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105 | .BR closedir (3), |
106 | .BR opendir (3), | |
107 | .BR readdir (3), | |
108 | .BR rewinddir (3), | |
109 | .BR scandir (3), | |
110 | .BR seekdir (3) |