1dirent.h(0P) POSIX Programmer's Manual dirent.h(0P)
2
3
4
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 dirent.h — format of directory entries
13
15 #include <dirent.h>
16
18 The internal format of directories is unspecified.
19
20 The <dirent.h> header shall define the following type:
21
22 DIR A type representing a directory stream. The DIR type may be an
23 incomplete type.
24
25 It shall also define the structure dirent which shall include the fol‐
26 lowing members:
27
28
29 ino_t d_ino File serial number.
30 char d_name[] Filename string of entry.
31
32 The <dirent.h> header shall define the ino_t type as described in
33 <sys/types.h>.
34
35 The array d_name is of unspecified size, but shall contain a filename
36 of at most {NAME_MAX} bytes followed by a terminating null byte.
37
38 The following shall be declared as functions and may also be defined as
39 macros. Function prototypes shall be provided.
40
41
42 int alphasort(const struct dirent **, const struct dirent **);
43 int closedir(DIR *);
44 int dirfd(DIR *);
45 DIR *fdopendir(int);
46 DIR *opendir(const char *);
47 struct dirent *readdir(DIR *);
48 int readdir_r(DIR *restrict, struct dirent *restrict,
49 struct dirent **restrict);
50 void rewinddir(DIR *);
51 int scandir(const char *, struct dirent ***,
52 int (*)(const struct dirent *),
53 int (*)(const struct dirent **,
54 const struct dirent **));
55 void seekdir(DIR *, long);
56 long telldir(DIR *);
57
58 The following sections are informative.
59
61 None.
62
64 Information similar to that in the <dirent.h> header is contained in a
65 file <sys/dir.h> in 4.2 BSD and 4.3 BSD. The equivalent in these imple‐
66 mentations of struct dirent from this volume of POSIX.1‐2017 is struct
67 direct. The filename was changed because the name <sys/dir.h> was also
68 used in earlier implementations to refer to definitions related to the
69 older access method; this produced name conflicts. The name of the
70 structure was changed because this volume of POSIX.1‐2017 does not com‐
71 pletely define what is in the structure, so it could be different on
72 some implementations from struct direct.
73
74 The name of an array of char of an unspecified size should not be used
75 as an lvalue. Use of:
76
77
78 sizeof(d_name)
79
80 is incorrect; use:
81
82
83 strlen(d_name)
84
85 instead.
86
87 The array of char d_name is not a fixed size. Implementations may need
88 to declare struct dirent with an array size for d_name of 1, but the
89 actual number of bytes provided matches (or only slightly exceeds) the
90 length of the filename string.
91
93 None.
94
96 <sys_types.h>
97
98 The System Interfaces volume of POSIX.1‐2017, alphasort(), closedir(),
99 dirfd(), fdopendir(), readdir(), rewinddir(), seekdir(), telldir()
100
102 Portions of this text are reprinted and reproduced in electronic form
103 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
104 table Operating System Interface (POSIX), The Open Group Base Specifi‐
105 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
106 Electrical and Electronics Engineers, Inc and The Open Group. In the
107 event of any discrepancy between this version and the original IEEE and
108 The Open Group Standard, the original IEEE and The Open Group Standard
109 is the referee document. The original Standard can be obtained online
110 at http://www.opengroup.org/unix/online.html .
111
112 Any typographical or formatting errors that appear in this page are
113 most likely to have been introduced during the conversion of the source
114 files to man page format. To report such errors, see https://www.ker‐
115 nel.org/doc/man-pages/reporting_bugs.html .
116
117
118
119IEEE/The Open Group 2017 dirent.h(0P)