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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14 | .\" manual page may be incorrect or out-of-date.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 | .\" | |
4b8c67d9 | 62 | .TH SCANDIR 3 2017-09-15 "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> | |
68e4db0a | 69 | .PP |
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 | 74 | .RE |
68e4db0a | 75 | .PP |
ecf9e5f8 | 76 | .BI "int alphasort(const struct dirent **" a ", const struct dirent **" b ); |
68e4db0a | 77 | .PP |
ecf9e5f8 | 78 | .BI "int versionsort(const struct dirent **" a ", const struct dirent **" b ); |
ef097103 MK |
79 | |
80 | .BR "#include <fcntl.h>" " /* Definition of AT_* constants */" | |
81 | .B #include <dirent.h> | |
68e4db0a | 82 | .PP |
ef097103 MK |
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 |
68e4db0a | 92 | .PP |
cc4615cc MK |
93 | .in -4n |
94 | Feature Test Macro Requirements for glibc (see | |
95 | .BR feature_test_macros (7)): | |
96 | .in | |
68e4db0a | 97 | .PP |
cc4615cc MK |
98 | .BR scandir (), |
99 | .BR alphasort (): | |
4a8961c3 MK |
100 | .br |
101 | .RS 4 | |
102 | .PD 0 | |
78e3b458 | 103 | .ad b |
a30128b4 MK |
104 | /* Since glibc 2.10: */ _POSIX_C_SOURCE\ >=\ 200809L |
105 | || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE | |
4a8961c3 MK |
106 | .PD |
107 | .RE | |
68e4db0a | 108 | .PP |
cc4615cc MK |
109 | .BR versionsort (): |
110 | _GNU_SOURCE | |
68e4db0a | 111 | .PP |
ef097103 MK |
112 | .BR scandirat (): |
113 | _GNU_SOURCE | |
fea681da | 114 | .SH DESCRIPTION |
60a90ecd MK |
115 | The |
116 | .BR scandir () | |
6dea120e | 117 | function scans the directory \fIdirp\fP, calling |
c13182ef MK |
118 | \fIfilter\fP() on each directory entry. |
119 | Entries for which | |
c7094399 | 120 | \fIfilter\fP() returns nonzero are stored in strings allocated via |
60a90ecd MK |
121 | .BR malloc (3), |
122 | sorted using | |
123 | .BR qsort (3) | |
124 | with the comparison | |
63aa9df0 | 125 | function \fIcompar\fP(), and collected in array \fInamelist\fP |
60a90ecd MK |
126 | which is allocated via |
127 | .BR malloc (3). | |
fea681da | 128 | If \fIfilter\fP is NULL, all entries are selected. |
dd3568a1 | 129 | .PP |
fea681da | 130 | The |
63aa9df0 | 131 | .BR alphasort () |
fea681da | 132 | and |
63aa9df0 | 133 | .BR versionsort () |
fea681da | 134 | functions can be used as the comparison function |
63aa9df0 | 135 | .IR compar (). |
fea681da MK |
136 | The former sorts directory entries using |
137 | .BR strcoll (3), | |
138 | the latter using | |
4d52e8f8 | 139 | .BR strverscmp (3) |
8c383102 | 140 | on the strings \fI(*a)\->d_name\fP and \fI(*b)\->d_name\fP. |
ef097103 MK |
141 | .SS scandirat() |
142 | The | |
143 | .BR scandirat () | |
78e3b458 | 144 | function operates in exactly the same way as |
d0aa8720 | 145 | .BR scandir (), |
ef097103 | 146 | except for the differences described here. |
847e0d88 | 147 | .PP |
ef097103 MK |
148 | If the pathname given in |
149 | .I dirp | |
150 | is relative, then it is interpreted relative to the directory | |
151 | referred to by the file descriptor | |
152 | .I dirfd | |
153 | (rather than relative to the current working directory of | |
154 | the calling process, as is done by | |
d0aa8720 | 155 | .BR scandir () |
ef097103 | 156 | for a relative pathname). |
847e0d88 | 157 | .PP |
ef097103 MK |
158 | If |
159 | .I dirp | |
160 | is relative and | |
161 | .I dirfd | |
162 | is the special value | |
163 | .BR AT_FDCWD , | |
164 | then | |
165 | .I dirp | |
166 | is interpreted relative to the current working | |
167 | directory of the calling process (like | |
d0aa8720 | 168 | .BR scandir ()). |
847e0d88 | 169 | .PP |
ef097103 MK |
170 | If |
171 | .I dirp | |
172 | is absolute, then | |
173 | .I dirfd | |
174 | is ignored. | |
175 | .PP | |
176 | See | |
177 | .BR openat (2) | |
178 | for an explanation of the need for | |
179 | .BR scandirat (). | |
47297adb | 180 | .SH RETURN VALUE |
60a90ecd MK |
181 | The |
182 | .BR scandir () | |
183 | function returns the number of directory entries | |
fd88c684 MK |
184 | selected. |
185 | On error, \-1 is returned, with | |
186 | .I errno | |
187 | set to indicate the cause of the error. | |
fea681da MK |
188 | .PP |
189 | The | |
63aa9df0 | 190 | .BR alphasort () |
fea681da | 191 | and |
63aa9df0 | 192 | .BR versionsort () |
c13182ef MK |
193 | functions return an integer less than, equal to, |
194 | or greater than zero if the first argument is considered to be | |
fea681da MK |
195 | respectively less than, equal to, or greater than the second. |
196 | .SH ERRORS | |
197 | .TP | |
cb06e4a5 MF |
198 | .B ENOENT |
199 | The path in \fIdirp\fR does not exist. | |
200 | .TP | |
fea681da MK |
201 | .B ENOMEM |
202 | Insufficient memory to complete the operation. | |
cb06e4a5 MF |
203 | .TP |
204 | .B ENOTDIR | |
205 | The path in \fIdirp\fR is not a directory. | |
ef097103 MK |
206 | .PP |
207 | The following additional errors can occur for | |
208 | .BR scandirat (): | |
209 | .TP | |
210 | .B EBADF | |
211 | .I dirfd | |
212 | is not a valid file descriptor. | |
213 | .TP | |
214 | .B ENOTDIR | |
215 | .I dirp | |
216 | is a relative path and | |
217 | .I dirfd | |
218 | is a file descriptor referring to a file other than a directory. | |
7a4b8d36 MK |
219 | .SH VERSIONS |
220 | .BR versionsort () | |
221 | was added to glibc in version 2.1. | |
847e0d88 | 222 | .PP |
ef097103 MK |
223 | .BR scandirat () |
224 | was added to glibc in version 2.15. | |
9ec9e827 ZL |
225 | .SH ATTRIBUTES |
226 | For an explanation of the terms used in this section, see | |
227 | .BR attributes (7). | |
228 | .TS | |
229 | allbox; | |
230 | lbw26 lb lb | |
231 | l l l. | |
232 | Interface Attribute Value | |
233 | T{ | |
234 | .BR scandir (), | |
235 | .BR scandirat () | |
236 | T} Thread safety MT-Safe | |
237 | T{ | |
238 | .BR alphasort (), | |
239 | .BR versionsort () | |
240 | T} Thread safety MT-Safe locale | |
241 | .TE | |
847e0d88 | 242 | .sp 1 |
47297adb | 243 | .SH CONFORMING TO |
b86e869f MK |
244 | .BR alphasort (), |
245 | .BR scandir (): | |
4046f0e0 | 246 | 4.3BSD, POSIX.1-2008. |
847e0d88 | 247 | .PP |
2da325d7 | 248 | .BR versionsort () |
b86e869f | 249 | and |
ef097103 | 250 | .BR scandirat () |
b86e869f | 251 | are GNU extensions. |
4046f0e0 MK |
252 | .\" .LP |
253 | .\" The functions | |
254 | .\" .BR scandir () | |
255 | .\" and | |
256 | .\" .BR alphasort () | |
257 | .\" are from 4.3BSD, and have been available under Linux since libc4. | |
258 | .\" Libc4 and libc5 use the more precise prototype | |
259 | .\" .sp | |
260 | .\" .nf | |
261 | .\" int alphasort(const struct dirent ** a, | |
262 | .\" const struct dirent **b); | |
263 | .\" .fi | |
264 | .\" .sp | |
265 | .\" but glibc 2.0 returns to the imprecise BSD prototype. | |
6f695bc0 | 266 | .SH NOTES |
fea681da | 267 | Since glibc 2.1, |
63aa9df0 | 268 | .BR alphasort () |
fea681da MK |
269 | calls |
270 | .BR strcoll (3); | |
271 | earlier it used | |
272 | .BR strcmp (3). | |
847e0d88 | 273 | .PP |
57cc00ec MK |
274 | Before glibc 2.10, the two arguments of |
275 | .BR alphasort () | |
276 | and | |
277 | .BR versionsort () | |
278 | were typed as | |
279 | .IR "const void\ *" . | |
280 | When | |
281 | .BR alphasort () | |
282 | was standardized in POSIX.1-2008, | |
283 | the argument type was specified as the type-safe | |
284 | .IR "const struct dirent\ **", | |
285 | and glibc 2.10 changed the definition of | |
286 | .BR alphasort () | |
287 | (and the nonstandard | |
288 | .BR versionsort ()) | |
289 | to match the standard. | |
fea681da | 290 | .SH EXAMPLE |
e1d2d774 MK |
291 | The program below prints a list of the files in the current directory |
292 | in reverse order. | |
293 | .\" | |
294 | .SS Program source | |
295 | \& | |
e7d0bb47 | 296 | .EX |
5e84ae6c | 297 | #define _DEFAULT_SOURCE |
fea681da | 298 | #include <dirent.h> |
5e84ae6c MK |
299 | #include <stdio.h> |
300 | #include <stdlib.h> | |
cf0a9ace MK |
301 | |
302 | int | |
303 | main(void) | |
304 | { | |
fea681da MK |
305 | struct dirent **namelist; |
306 | int n; | |
307 | ||
3326bd19 | 308 | n = scandir(".", &namelist, NULL, alphasort); |
9a96fb65 | 309 | if (n == -1) { |
fea681da | 310 | perror("scandir"); |
9a96fb65 | 311 | exit(EXIT_FAILURE); |
fea681da | 312 | } |
9a96fb65 MK |
313 | |
314 | while (n\-\-) { | |
315 | printf("%s\en", namelist[n]\->d_name); | |
316 | free(namelist[n]); | |
317 | } | |
318 | free(namelist); | |
319 | ||
5e84ae6c | 320 | exit(EXIT_SUCCESS); |
fea681da | 321 | } |
e7d0bb47 | 322 | .EE |
47297adb | 323 | .SH SEE ALSO |
fea681da MK |
324 | .BR closedir (3), |
325 | .BR fnmatch (3), | |
326 | .BR opendir (3), | |
327 | .BR readdir (3), | |
328 | .BR rewinddir (3), | |
329 | .BR seekdir (3), | |
330 | .BR strcmp (3), | |
331 | .BR strcoll (3), | |
332 | .BR strverscmp (3), | |
333 | .BR telldir (3) |