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1 | .\" Copyright (C) 1993 David Metcalfe (david@prism.demon.co.uk) |
2 | .\" | |
93015253 | 3 | .\" %%%LICENSE_START(VERBATIM) |
fea681da MK |
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 | .\" |
fea681da MK |
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14 | .\" manual page may be incorrect or out-of-date.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 | .\" |
fea681da MK |
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 |
fea681da MK |
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 18:26:16 1993 by Rik Faith (faith@cs.unc.edu) | |
30 | .\" Modified Thu Apr 11 17:11:33 1996 by Andries Brouwer (aeb@cwi.nl): | |
31 | .\" Corrected type of compar routines, as suggested by | |
32 | .\" Miguel Barreiro (enano@avalon.yaix.es). Added example. | |
33 | .\" Modified Sun Sep 24 20:15:46 2000 by aeb, following Petter Reinholdtsen. | |
34 | .\" Modified 2001-12-26 by aeb, following Joey. Added versionsort. | |
35 | .\" | |
ef097103 MK |
36 | .\" The pieces on scandirat(3) were copyright and licensed as follows. |
37 | .\" | |
38 | .\" Copyright (c) 2012, Mark R. Bannister <cambridge@users.sourceforge.net> | |
39 | .\" based on text in mkfifoat.3 Copyright (c) 2006, Michael Kerrisk | |
40 | .\" | |
41 | .\" %%%LICENSE_START(GPLv2+_DOC_FULL) | |
42 | .\" This is free documentation; you can redistribute it and/or | |
43 | .\" modify it under the terms of the GNU General Public License as | |
44 | .\" published by the Free Software Foundation; either version 2 of | |
45 | .\" the License, or (at your option) any later version. | |
46 | .\" | |
47 | .\" The GNU General Public License's references to "object code" | |
48 | .\" and "executables" are to be interpreted as the output of any | |
49 | .\" document formatting or typesetting system, including | |
50 | .\" intermediate and printed output. | |
51 | .\" | |
52 | .\" This manual is distributed in the hope that it will be useful, | |
53 | .\" but WITHOUT ANY WARRANTY; without even the implied warranty of | |
54 | .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
55 | .\" GNU General Public License for more details. | |
56 | .\" | |
57 | .\" You should have received a copy of the GNU General Public | |
58 | .\" License along with this manual; if not, see | |
59 | .\" <http://www.gnu.org/licenses/>. | |
60 | .\" %%%LICENSE_END | |
61 | .\" | |
62 | .TH SCANDIR 3 2014-02-21 "GNU" "Linux Programmer's Manual" | |
fea681da | 63 | .SH NAME |
ef097103 MK |
64 | scandir, scandirat, alphasort, versionsort \- scan |
65 | a directory for matching entries | |
fea681da MK |
66 | .SH SYNOPSIS |
67 | .nf | |
68 | .B #include <dirent.h> | |
69 | .sp | |
6dea120e | 70 | .BI "int scandir(const char *" dirp ", struct dirent ***" namelist , |
fea681da | 71 | .RS |
a3887f6e MK |
72 | .BI "int (*" filter ")(const struct dirent *)," |
73 | .BI "int (*" compar ")(const struct dirent **, const struct dirent **));" | |
fea681da MK |
74 | .RE |
75 | .sp | |
76 | .BI "int alphasort(const void *" a ", const void *" b ); | |
cc4615cc | 77 | .sp |
fea681da | 78 | .BI "int versionsort(const void *" a ", const void *" b ); |
ef097103 MK |
79 | |
80 | .BR "#include <fcntl.h>" " /* Definition of AT_* constants */" | |
81 | .B #include <dirent.h> | |
82 | .sp | |
83 | .fi | |
84 | .BI "int scandirat(int " dirfd ", const char *" dirp "," | |
85 | .BI "struct dirent ***" namelist , | |
86 | .nf | |
87 | .RS | |
88 | .BI "int (*" filter ")(const struct dirent *)," | |
89 | .BI "int (*" compar ")(const struct dirent **, const struct dirent **));" | |
90 | .RE | |
fea681da | 91 | .fi |
cc4615cc MK |
92 | .sp |
93 | .in -4n | |
94 | Feature Test Macro Requirements for glibc (see | |
95 | .BR feature_test_macros (7)): | |
96 | .in | |
97 | .sp | |
98 | .BR scandir (), | |
99 | .BR alphasort (): | |
4a8961c3 MK |
100 | .br |
101 | .RS 4 | |
102 | .PD 0 | |
78e3b458 | 103 | .ad b |
cc4615cc MK |
104 | _BSD_SOURCE || _SVID_SOURCE |
105 | .br | |
4a8961c3 MK |
106 | || /* Since glibc 2.10: */ |
107 | .RS 4 | |
108 | (_POSIX_C_SOURCE\ >=\ 200809L || _XOPEN_SOURCE\ >=\ 700) | |
109 | .RE | |
110 | .PD | |
111 | .RE | |
ef097103 | 112 | .sp |
cc4615cc MK |
113 | .BR versionsort (): |
114 | _GNU_SOURCE | |
ef097103 MK |
115 | .sp |
116 | .BR scandirat (): | |
117 | _GNU_SOURCE | |
fea681da | 118 | .SH DESCRIPTION |
60a90ecd MK |
119 | The |
120 | .BR scandir () | |
6dea120e | 121 | function scans the directory \fIdirp\fP, calling |
c13182ef MK |
122 | \fIfilter\fP() on each directory entry. |
123 | Entries for which | |
c7094399 | 124 | \fIfilter\fP() returns nonzero are stored in strings allocated via |
60a90ecd MK |
125 | .BR malloc (3), |
126 | sorted using | |
127 | .BR qsort (3) | |
128 | with the comparison | |
63aa9df0 | 129 | function \fIcompar\fP(), and collected in array \fInamelist\fP |
60a90ecd MK |
130 | which is allocated via |
131 | .BR malloc (3). | |
fea681da MK |
132 | If \fIfilter\fP is NULL, all entries are selected. |
133 | .LP | |
134 | The | |
63aa9df0 | 135 | .BR alphasort () |
fea681da | 136 | and |
63aa9df0 | 137 | .BR versionsort () |
fea681da | 138 | functions can be used as the comparison function |
63aa9df0 | 139 | .IR compar (). |
fea681da MK |
140 | The former sorts directory entries using |
141 | .BR strcoll (3), | |
142 | the latter using | |
4d52e8f8 | 143 | .BR strverscmp (3) |
8c383102 | 144 | on the strings \fI(*a)\->d_name\fP and \fI(*b)\->d_name\fP. |
ef097103 MK |
145 | .SS scandirat() |
146 | The | |
147 | .BR scandirat () | |
78e3b458 | 148 | function operates in exactly the same way as |
ef097103 MK |
149 | .BR scandir (3), |
150 | except for the differences described here. | |
151 | ||
152 | If the pathname given in | |
153 | .I dirp | |
154 | is relative, then it is interpreted relative to the directory | |
155 | referred to by the file descriptor | |
156 | .I dirfd | |
157 | (rather than relative to the current working directory of | |
158 | the calling process, as is done by | |
159 | .BR scandir (3) | |
160 | for a relative pathname). | |
161 | ||
162 | If | |
163 | .I dirp | |
164 | is relative and | |
165 | .I dirfd | |
166 | is the special value | |
167 | .BR AT_FDCWD , | |
168 | then | |
169 | .I dirp | |
170 | is interpreted relative to the current working | |
171 | directory of the calling process (like | |
172 | .BR scandir (3)). | |
173 | ||
174 | If | |
175 | .I dirp | |
176 | is absolute, then | |
177 | .I dirfd | |
178 | is ignored. | |
179 | .PP | |
180 | See | |
181 | .BR openat (2) | |
182 | for an explanation of the need for | |
183 | .BR scandirat (). | |
47297adb | 184 | .SH RETURN VALUE |
60a90ecd MK |
185 | The |
186 | .BR scandir () | |
187 | function returns the number of directory entries | |
fd88c684 MK |
188 | selected. |
189 | On error, \-1 is returned, with | |
190 | .I errno | |
191 | set to indicate the cause of the error. | |
fea681da MK |
192 | .PP |
193 | The | |
63aa9df0 | 194 | .BR alphasort () |
fea681da | 195 | and |
63aa9df0 | 196 | .BR versionsort () |
c13182ef MK |
197 | functions return an integer less than, equal to, |
198 | or greater than zero if the first argument is considered to be | |
fea681da MK |
199 | respectively less than, equal to, or greater than the second. |
200 | .SH ERRORS | |
201 | .TP | |
cb06e4a5 MF |
202 | .B ENOENT |
203 | The path in \fIdirp\fR does not exist. | |
204 | .TP | |
fea681da MK |
205 | .B ENOMEM |
206 | Insufficient memory to complete the operation. | |
cb06e4a5 MF |
207 | .TP |
208 | .B ENOTDIR | |
209 | The path in \fIdirp\fR is not a directory. | |
ef097103 MK |
210 | .PP |
211 | The following additional errors can occur for | |
212 | .BR scandirat (): | |
213 | .TP | |
214 | .B EBADF | |
215 | .I dirfd | |
216 | is not a valid file descriptor. | |
217 | .TP | |
218 | .B ENOTDIR | |
219 | .I dirp | |
220 | is a relative path and | |
221 | .I dirfd | |
222 | is a file descriptor referring to a file other than a directory. | |
7a4b8d36 MK |
223 | .SH VERSIONS |
224 | .BR versionsort () | |
225 | was added to glibc in version 2.1. | |
ef097103 MK |
226 | |
227 | .BR scandirat () | |
228 | was added to glibc in version 2.15. | |
47297adb | 229 | .SH CONFORMING TO |
b86e869f MK |
230 | .BR alphasort (), |
231 | .BR scandir (): | |
232 | POSIX.1-2008. | |
233 | ||
2da325d7 | 234 | .BR versionsort () |
b86e869f | 235 | and |
ef097103 | 236 | .BR scandirat () |
b86e869f | 237 | are GNU extensions. |
fea681da MK |
238 | .LP |
239 | The functions | |
63aa9df0 | 240 | .BR scandir () |
fea681da | 241 | and |
63aa9df0 | 242 | .BR alphasort () |
b14d4aa5 | 243 | are from 4.3BSD, and have been available under Linux since libc4. |
fea681da MK |
244 | Libc4 and libc5 use the more precise prototype |
245 | .sp | |
246 | .nf | |
c13182ef | 247 | int alphasort(const struct dirent ** a, |
fecfb777 | 248 | const struct dirent **b); |
fea681da MK |
249 | .fi |
250 | .sp | |
251 | but glibc 2.0 returns to the imprecise BSD prototype. | |
6f695bc0 | 252 | .SH NOTES |
fea681da | 253 | Since glibc 2.1, |
63aa9df0 | 254 | .BR alphasort () |
fea681da MK |
255 | calls |
256 | .BR strcoll (3); | |
257 | earlier it used | |
258 | .BR strcmp (3). | |
259 | .SH EXAMPLE | |
260 | .nf | |
cc4615cc | 261 | #define _SVID_SOURCE |
fea681da MK |
262 | /* print files in current directory in reverse order */ |
263 | #include <dirent.h> | |
cf0a9ace MK |
264 | |
265 | int | |
266 | main(void) | |
267 | { | |
fea681da MK |
268 | struct dirent **namelist; |
269 | int n; | |
270 | ||
3326bd19 | 271 | n = scandir(".", &namelist, NULL, alphasort); |
fea681da MK |
272 | if (n < 0) |
273 | perror("scandir"); | |
274 | else { | |
d4949190 | 275 | while (n\-\-) { |
31a6818e | 276 | printf("%s\en", namelist[n]\->d_name); |
fea681da MK |
277 | free(namelist[n]); |
278 | } | |
279 | free(namelist); | |
280 | } | |
281 | } | |
282 | .fi | |
47297adb | 283 | .SH SEE ALSO |
fea681da MK |
284 | .BR closedir (3), |
285 | .BR fnmatch (3), | |
286 | .BR opendir (3), | |
287 | .BR readdir (3), | |
288 | .BR rewinddir (3), | |
289 | .BR seekdir (3), | |
290 | .BR strcmp (3), | |
291 | .BR strcoll (3), | |
292 | .BR strverscmp (3), | |
293 | .BR telldir (3) |