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1 | .\" $NetBSD: getdirentries.2,v 1.7 1995/10/12 15:40:50 jtc Exp $ |
2 | .\" | |
3 | .\" Copyright (c) 1989, 1991, 1993 | |
4 | .\" The Regents of the University of California. All rights reserved. | |
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7 | .\" modification, are permitted provided that the following conditions | |
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11 | .\" 2. Redistributions in binary form must reproduce the above copyright | |
12 | .\" notice, this list of conditions and the following disclaimer in the | |
13 | .\" documentation and/or other materials provided with the distribution. | |
14 | .\" 3. All advertising materials mentioning features or use of this software | |
15 | .\" must display the following acknowledgement: | |
16 | .\" This product includes software developed by the University of | |
17 | .\" California, Berkeley and its contributors. | |
18 | .\" 4. Neither the name of the University nor the names of its contributors | |
19 | .\" may be used to endorse or promote products derived from this software | |
20 | .\" without specific prior written permission. | |
21 | .\" | |
22 | .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
23 | .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
24 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
25 | .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
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32 | .\" SUCH DAMAGE. | |
33 | .\" | |
34 | .\" @(#)getdirentries.2 8.1 (Berkeley) 6/9/93 | |
35 | .\" | |
36 | .Dd June 9, 1993 | |
37 | .Dt GETDIRENTRIES 2 | |
38 | .Os | |
39 | .Sh NAME | |
40 | .Nm getdirentries | |
41 | .Nd "get directory entries in a filesystem independent format" | |
42 | .Sh SYNOPSIS | |
43 | .Fd #include <dirent.h> | |
44 | .Ft int | |
45 | .Fn getdirentries "int fd" "char *buf" "int nbytes" "long *basep" | |
46 | .Sh DESCRIPTION | |
47 | .Fn Getdirentries | |
48 | reads directory entries from the directory | |
49 | referenced by the file descriptor | |
50 | .Fa fd | |
51 | into the buffer pointed to by | |
52 | .Fa buf , | |
53 | in a filesystem independent format. | |
54 | Up to | |
55 | .Fa nbytes | |
56 | of data will be transferred. | |
57 | .Fa Nbytes | |
58 | must be greater than or equal to the | |
59 | block size associated with the file, | |
60 | see | |
61 | .Xr stat 2 . | |
62 | Some filesystems may not support | |
63 | .Fn getdirentries | |
64 | with buffers smaller than this size. | |
65 | .Pp | |
66 | The data in the buffer is a series of | |
67 | .Em dirent | |
68 | structures each containing the following entries: | |
69 | .Bd -literal -offset indent | |
70 | unsigned long d_fileno; | |
71 | unsigned short d_reclen; | |
72 | unsigned short d_namlen; | |
73 | char d_name[MAXNAMELEN + 1]; /* see below */ | |
74 | .Ed | |
75 | .Pp | |
76 | The | |
77 | .Fa d_fileno | |
78 | entry is a number which is unique for each | |
79 | distinct file in the filesystem. | |
80 | Files that are linked by hard links (see | |
81 | .Xr link 2 ) | |
82 | have the same | |
83 | .Fa d_fileno . | |
84 | The | |
85 | .Fa d_reclen | |
86 | entry is the length, in bytes, of the directory record. | |
87 | The | |
88 | .Fa d_name | |
89 | entry contains a null terminated file name. | |
90 | The | |
91 | .Fa d_namlen | |
92 | entry specifies the length of the file name excluding the null byte. | |
93 | Thus the actual size of | |
94 | .Fa d_name | |
95 | may vary from 1 to | |
96 | .Dv MAXNAMELEN | |
97 | \&+ 1. | |
98 | .Pp | |
99 | Entries may be separated by extra space. | |
100 | The | |
101 | .Fa d_reclen | |
102 | entry may be used as an offset from the start of a | |
103 | .Fa dirent | |
104 | structure to the next structure, if any. | |
105 | .Pp | |
106 | The actual number of bytes transferred is returned. | |
107 | The current position pointer associated with | |
108 | .Fa fd | |
109 | is set to point to the next block of entries. | |
110 | The pointer may not advance by the number of bytes returned by | |
111 | .Fn getdirentries . | |
112 | A value of zero is returned when | |
113 | the end of the directory has been reached. | |
114 | .Pp | |
115 | .Fn Getdirentries | |
116 | writes the position of the block read into the location pointed to by | |
117 | .Fa basep . | |
118 | Alternatively, the current position pointer may be set and retrieved by | |
119 | .Xr lseek 2 . | |
120 | The current position pointer should only be set to a value returned by | |
121 | .Xr lseek 2 , | |
122 | a value returned in the location pointed to by | |
123 | .Fa basep , | |
124 | or zero. | |
125 | .Sh RETURN VALUES | |
126 | If successful, the number of bytes actually transferred is returned. | |
127 | Otherwise, -1 is returned and the global variable | |
128 | .Va errno | |
129 | is set to indicate the error. | |
130 | .Sh ERRORS | |
131 | .Fn Getdirentries | |
132 | will fail if: | |
133 | .Bl -tag -width Er | |
134 | .It Bq Er EBADF | |
135 | .Fa fd | |
136 | is not a valid file descriptor open for reading. | |
137 | .It Bq Er EFAULT | |
138 | Either | |
139 | .Fa buf | |
140 | or | |
141 | .Fa basep | |
142 | point outside the allocated address space. | |
143 | .It Bq Er EIO | |
144 | An | |
145 | .Tn I/O | |
146 | error occurred while reading from or writing to the file system. | |
147 | .El | |
148 | .Sh SEE ALSO | |
149 | .Xr open 2 , | |
150 | .Xr lseek 2 | |
151 | .Sh HISTORY | |
152 | The | |
153 | .Fn getdirentries | |
154 | function first appeared in 4.4BSD. |