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1 | .\" Copyright (C) 1993 David Metcalfe (david@prism.demon.co.uk) |
2 | .\" | |
3 | .\" Permission is granted to make and distribute verbatim copies of this | |
4 | .\" manual provided the copyright notice and this permission notice are | |
5 | .\" preserved on all copies. | |
6 | .\" | |
7 | .\" Permission is granted to copy and distribute modified versions of this | |
8 | .\" manual under the conditions for verbatim copying, provided that the | |
9 | .\" entire resulting derived work is distributed under the terms of a | |
10 | .\" permission notice identical to this one. | |
11 | .\" | |
12 | .\" Since the Linux kernel and libraries are constantly changing, this | |
13 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
14 | .\" responsibility for errors or omissions, or for damages resulting from | |
15 | .\" the use of the information contained herein. The author(s) may not | |
16 | .\" have taken the same level of care in the production of this manual, | |
17 | .\" which is licensed free of charge, as they might when working | |
18 | .\" professionally. | |
19 | .\" | |
20 | .\" Formatted or processed versions of this manual, if unaccompanied by | |
21 | .\" the source, must acknowledge the copyright and authors of this work. | |
22 | .\" | |
23 | .\" References consulted: | |
24 | .\" Linux libc source code | |
25 | .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) | |
26 | .\" 386BSD man pages | |
27 | .\" Modified Sat Jul 24 18:26:16 1993 by Rik Faith (faith@cs.unc.edu) | |
28 | .\" Modified Thu Apr 11 17:11:33 1996 by Andries Brouwer (aeb@cwi.nl): | |
29 | .\" Corrected type of compar routines, as suggested by | |
30 | .\" Miguel Barreiro (enano@avalon.yaix.es). Added example. | |
31 | .\" Modified Sun Sep 24 20:15:46 2000 by aeb, following Petter Reinholdtsen. | |
32 | .\" Modified 2001-12-26 by aeb, following Joey. Added versionsort. | |
33 | .\" | |
34 | .TH SCANDIR 3 2001-12-26 "GNU" "Linux Programmer's Manual" | |
35 | .SH NAME | |
36 | scandir, alphasort, versionsort \- scan a directory for matching entries | |
37 | .SH SYNOPSIS | |
38 | .nf | |
39 | .B #include <dirent.h> | |
40 | .sp | |
41 | .BI "int scandir(const char *" dir ", struct dirent ***" namelist , | |
42 | .RS | |
43 | .BI "int(*" filter ")(const struct dirent *)," | |
44 | .BI "int(*" compar ")(const struct dirent **, const struct dirent **));" | |
45 | .RE | |
46 | .sp | |
47 | .BI "int alphasort(const void *" a ", const void *" b ); | |
48 | .br | |
49 | .BI "int versionsort(const void *" a ", const void *" b ); | |
50 | .fi | |
51 | .SH DESCRIPTION | |
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52 | The \fBscandir\fP() function scans the directory \fIdir\fP, calling |
53 | \fIfilter\fP() on each directory entry. Entries for which | |
54 | \fIfilter\fP() returns non-zero are stored in strings allocated via | |
55 | \fBmalloc\fP(), sorted using \fBqsort\fP() with the comparison | |
56 | function \fIcompar\fP(), and collected in array \fInamelist\fP | |
57 | which is allocated via \fBmalloc\fP(). | |
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58 | If \fIfilter\fP is NULL, all entries are selected. |
59 | .LP | |
60 | The | |
63aa9df0 | 61 | .BR alphasort () |
fea681da | 62 | and |
63aa9df0 | 63 | .BR versionsort () |
fea681da | 64 | functions can be used as the comparison function |
63aa9df0 | 65 | .IR compar (). |
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66 | The former sorts directory entries using |
67 | .BR strcoll (3), | |
68 | the latter using | |
4d52e8f8 | 69 | .BR strverscmp (3) |
8c383102 | 70 | on the strings \fI(*a)\->d_name\fP and \fI(*b)\->d_name\fP. |
fea681da | 71 | .SH "RETURN VALUE" |
63aa9df0 | 72 | The \fBscandir\fP() function returns the number of directory entries |
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73 | selected or \-1 if an error occurs. |
74 | .PP | |
75 | The | |
63aa9df0 | 76 | .BR alphasort () |
fea681da | 77 | and |
63aa9df0 | 78 | .BR versionsort () |
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79 | functions return an integer less than, equal to, |
80 | or greater than zero if the first argument is considered to be | |
81 | respectively less than, equal to, or greater than the second. | |
82 | .SH ERRORS | |
83 | .TP | |
84 | .B ENOMEM | |
85 | Insufficient memory to complete the operation. | |
86 | .SH "CONFORMING TO" | |
a7fadb55 | 87 | None of these functions is in POSIX.1-2001, but |
63aa9df0 | 88 | .BR alphasort () |
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89 | and |
90 | .BR scandir () | |
91 | are under consideration for a future revision to POSIX.1. | |
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92 | .LP |
93 | The functions | |
63aa9df0 | 94 | .BR scandir () |
fea681da | 95 | and |
63aa9df0 | 96 | .BR alphasort () |
b14d4aa5 | 97 | are from 4.3BSD, and have been available under Linux since libc4. |
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98 | Libc4 and libc5 use the more precise prototype |
99 | .sp | |
100 | .nf | |
fecfb777 MK |
101 | int alphasort(const struct dirent ** a, |
102 | const struct dirent **b); | |
fea681da MK |
103 | .fi |
104 | .sp | |
105 | but glibc 2.0 returns to the imprecise BSD prototype. | |
106 | .LP | |
107 | The function | |
63aa9df0 | 108 | .BR versionsort () |
fea681da | 109 | is a GNU extension, available since glibc 2.1. |
fecfb777 | 110 | .LP |
fea681da | 111 | Since glibc 2.1, |
63aa9df0 | 112 | .BR alphasort () |
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113 | calls |
114 | .BR strcoll (3); | |
115 | earlier it used | |
116 | .BR strcmp (3). | |
117 | .SH EXAMPLE | |
118 | .nf | |
119 | /* print files in current directory in reverse order */ | |
120 | #include <dirent.h> | |
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121 | |
122 | int | |
123 | main(void) | |
124 | { | |
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125 | struct dirent **namelist; |
126 | int n; | |
127 | ||
128 | n = scandir(".", &namelist, 0, alphasort); | |
129 | if (n < 0) | |
130 | perror("scandir"); | |
131 | else { | |
2bc2f479 MK |
132 | while(n\-\-) { |
133 | printf("%s\en", namelist[n]\->d_name); | |
fea681da MK |
134 | free(namelist[n]); |
135 | } | |
136 | free(namelist); | |
137 | } | |
138 | } | |
139 | .fi | |
140 | .SH "SEE ALSO" | |
141 | .BR closedir (3), | |
142 | .BR fnmatch (3), | |
143 | .BR opendir (3), | |
144 | .BR readdir (3), | |
145 | .BR rewinddir (3), | |
146 | .BR seekdir (3), | |
147 | .BR strcmp (3), | |
148 | .BR strcoll (3), | |
149 | .BR strverscmp (3), | |
150 | .BR telldir (3) |