1 .\" Copyright (C) 1993 David Metcalfe (david@prism.demon.co.uk)
3 .\" %%%LICENSE_START(VERBATIM)
4 .\" Permission is granted to make and distribute verbatim copies of this
5 .\" manual provided the copyright notice and this permission notice are
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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.
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14 .\" manual page may be incorrect or out-of-date.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
21 .\" Formatted or processed versions of this manual, if unaccompanied by
22 .\" the source, must acknowledge the copyright and authors of this work.
25 .\" References consulted:
26 .\" Linux libc source code
27 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
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.
36 .\" The pieces on scandirat(3) were copyright and licensed as follows.
38 .\" Copyright (c) 2012, Mark R. Bannister <cambridge@users.sourceforge.net>
39 .\" based on text in mkfifoat.3 Copyright (c) 2006, Michael Kerrisk
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55 .\" GNU General Public License for more details.
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/>.
62 .TH SCANDIR 3 2014-05-28 "GNU" "Linux Programmer's Manual"
64 scandir, scandirat, alphasort, versionsort \- scan
65 a directory for matching entries
68 .B #include <dirent.h>
70 .BI "int scandir(const char *" dirp ", struct dirent ***" namelist ,
72 .BI "int (*" filter ")(const struct dirent *),"
73 .BI "int (*" compar ")(const struct dirent **, const struct dirent **));"
76 .BI "int alphasort(const struct dirent **" a ", const struct dirent **" b );
78 .BI "int versionsort(const struct dirent **" a ", const struct dirent **" b );
80 .BR "#include <fcntl.h>" " /* Definition of AT_* constants */"
81 .B #include <dirent.h>
84 .BI "int scandirat(int " dirfd ", const char *" dirp ","
85 .BI "struct dirent ***" namelist ,
88 .BI "int (*" filter ")(const struct dirent *),"
89 .BI "int (*" compar ")(const struct dirent **, const struct dirent **));"
94 Feature Test Macro Requirements for glibc (see
95 .BR feature_test_macros (7)):
104 _BSD_SOURCE || _SVID_SOURCE
106 || /* Since glibc 2.10: */
108 (_POSIX_C_SOURCE\ >=\ 200809L || _XOPEN_SOURCE\ >=\ 700)
121 function scans the directory \fIdirp\fP, calling
122 \fIfilter\fP() on each directory entry.
124 \fIfilter\fP() returns nonzero are stored in strings allocated via
129 function \fIcompar\fP(), and collected in array \fInamelist\fP
130 which is allocated via
132 If \fIfilter\fP is NULL, all entries are selected.
138 functions can be used as the comparison function
140 The former sorts directory entries using
144 on the strings \fI(*a)\->d_name\fP and \fI(*b)\->d_name\fP.
148 function operates in exactly the same way as
150 except for the differences described here.
152 If the pathname given in
154 is relative, then it is interpreted relative to the directory
155 referred to by the file descriptor
157 (rather than relative to the current working directory of
158 the calling process, as is done by
160 for a relative pathname).
170 is interpreted relative to the current working
171 directory of the calling process (like
182 for an explanation of the need for
187 function returns the number of directory entries
189 On error, \-1 is returned, with
191 set to indicate the cause of the error.
197 functions return an integer less than, equal to,
198 or greater than zero if the first argument is considered to be
199 respectively less than, equal to, or greater than the second.
203 The path in \fIdirp\fR does not exist.
206 Insufficient memory to complete the operation.
209 The path in \fIdirp\fR is not a directory.
211 The following additional errors can occur for
216 is not a valid file descriptor.
220 is a relative path and
222 is a file descriptor referring to a file other than a directory.
225 was added to glibc in version 2.1.
228 was added to glibc in version 2.15.
232 4.3BSD, POSIX.1-2008.
243 .\" are from 4.3BSD, and have been available under Linux since libc4.
244 .\" Libc4 and libc5 use the more precise prototype
247 .\" int alphasort(const struct dirent ** a,
248 .\" const struct dirent **b);
251 .\" but glibc 2.0 returns to the imprecise BSD prototype.
262 /* print files in current directory in reverse order */
268 struct dirent **namelist;
271 n = scandir(".", &namelist, NULL, alphasort);
276 printf("%s\en", namelist[n]\->d_name);