mirror of https://github.com/mkerrisk/man-pages
184 lines
4.8 KiB
Groff
184 lines
4.8 KiB
Groff
.\" Copyright (C) 1993 David Metcalfe (david@prism.demon.co.uk)
|
|
.\"
|
|
.\" Permission is granted to make and distribute verbatim copies of this
|
|
.\" manual provided the copyright notice and this permission notice are
|
|
.\" preserved on all copies.
|
|
.\"
|
|
.\" Permission is granted to copy and distribute modified versions of this
|
|
.\" manual under the conditions for verbatim copying, provided that the
|
|
.\" entire resulting derived work is distributed under the terms of a
|
|
.\" permission notice identical to this one.
|
|
.\"
|
|
.\" Since the Linux kernel and libraries are constantly changing, this
|
|
.\" manual page may be incorrect or out-of-date. The author(s) assume no
|
|
.\" responsibility for errors or omissions, or for damages resulting from
|
|
.\" the use of the information contained herein. The author(s) may not
|
|
.\" have taken the same level of care in the production of this manual,
|
|
.\" which is licensed free of charge, as they might when working
|
|
.\" professionally.
|
|
.\"
|
|
.\" Formatted or processed versions of this manual, if unaccompanied by
|
|
.\" the source, must acknowledge the copyright and authors of this work.
|
|
.\"
|
|
.\" References consulted:
|
|
.\" Linux libc source code
|
|
.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
|
|
.\" 386BSD man pages
|
|
.\" Modified Sat Jul 24 18:26:16 1993 by Rik Faith (faith@cs.unc.edu)
|
|
.\" Modified Thu Apr 11 17:11:33 1996 by Andries Brouwer (aeb@cwi.nl):
|
|
.\" Corrected type of compar routines, as suggested by
|
|
.\" Miguel Barreiro (enano@avalon.yaix.es). Added example.
|
|
.\" Modified Sun Sep 24 20:15:46 2000 by aeb, following Petter Reinholdtsen.
|
|
.\" Modified 2001-12-26 by aeb, following Joey. Added versionsort.
|
|
.\"
|
|
.TH SCANDIR 3 2012-04-26 "GNU" "Linux Programmer's Manual"
|
|
.SH NAME
|
|
scandir, alphasort, versionsort \- scan a directory for matching entries
|
|
.SH SYNOPSIS
|
|
.nf
|
|
.B #include <dirent.h>
|
|
.sp
|
|
.BI "int scandir(const char *" dirp ", struct dirent ***" namelist ,
|
|
.RS
|
|
.BI "int (*" filter ")(const struct dirent *),"
|
|
.BI "int (*" compar ")(const struct dirent **, const struct dirent **));"
|
|
.RE
|
|
.sp
|
|
.BI "int alphasort(const void *" a ", const void *" b );
|
|
.sp
|
|
.BI "int versionsort(const void *" a ", const void *" b );
|
|
.fi
|
|
.sp
|
|
.in -4n
|
|
Feature Test Macro Requirements for glibc (see
|
|
.BR feature_test_macros (7)):
|
|
.in
|
|
.sp
|
|
.BR scandir (),
|
|
.BR alphasort ():
|
|
_BSD_SOURCE || _SVID_SOURCE
|
|
.br
|
|
.BR versionsort ():
|
|
_GNU_SOURCE
|
|
.SH DESCRIPTION
|
|
The
|
|
.BR scandir ()
|
|
function scans the directory \fIdirp\fP, calling
|
|
\fIfilter\fP() on each directory entry.
|
|
Entries for which
|
|
\fIfilter\fP() returns nonzero are stored in strings allocated via
|
|
.BR malloc (3),
|
|
sorted using
|
|
.BR qsort (3)
|
|
with the comparison
|
|
function \fIcompar\fP(), and collected in array \fInamelist\fP
|
|
which is allocated via
|
|
.BR malloc (3).
|
|
If \fIfilter\fP is NULL, all entries are selected.
|
|
.LP
|
|
The
|
|
.BR alphasort ()
|
|
and
|
|
.BR versionsort ()
|
|
functions can be used as the comparison function
|
|
.IR compar ().
|
|
The former sorts directory entries using
|
|
.BR strcoll (3),
|
|
the latter using
|
|
.BR strverscmp (3)
|
|
on the strings \fI(*a)\->d_name\fP and \fI(*b)\->d_name\fP.
|
|
.SH "RETURN VALUE"
|
|
The
|
|
.BR scandir ()
|
|
function returns the number of directory entries
|
|
selected or \-1 if an error occurs.
|
|
.PP
|
|
The
|
|
.BR alphasort ()
|
|
and
|
|
.BR versionsort ()
|
|
functions return an integer less than, equal to,
|
|
or greater than zero if the first argument is considered to be
|
|
respectively less than, equal to, or greater than the second.
|
|
.SH ERRORS
|
|
.TP
|
|
.B ENOENT
|
|
The path in \fIdirp\fR does not exist.
|
|
.TP
|
|
.B ENOMEM
|
|
Insufficient memory to complete the operation.
|
|
.TP
|
|
.B ENOTDIR
|
|
The path in \fIdirp\fR is not a directory.
|
|
.SH VERSIONS
|
|
.BR versionsort ()
|
|
was added to glibc in version 2.1.
|
|
.SH "CONFORMING TO"
|
|
.BR alphasort ()
|
|
and
|
|
.BR scandir ()
|
|
are specified in POSIX.1-2008, and are widely available.
|
|
.BR versionsort ()
|
|
is a GNU extension.
|
|
.LP
|
|
The functions
|
|
.BR scandir ()
|
|
and
|
|
.BR alphasort ()
|
|
are from 4.3BSD, and have been available under Linux since libc4.
|
|
Libc4 and libc5 use the more precise prototype
|
|
.sp
|
|
.nf
|
|
int alphasort(const struct dirent ** a,
|
|
const struct dirent **b);
|
|
.fi
|
|
.sp
|
|
but glibc 2.0 returns to the imprecise BSD prototype.
|
|
.LP
|
|
The function
|
|
.BR versionsort ()
|
|
is a GNU extension, available since glibc 2.1.
|
|
.LP
|
|
Since glibc 2.1,
|
|
.BR alphasort ()
|
|
calls
|
|
.BR strcoll (3);
|
|
earlier it used
|
|
.BR strcmp (3).
|
|
.SH EXAMPLE
|
|
.nf
|
|
#define _SVID_SOURCE
|
|
/* print files in current directory in reverse order */
|
|
#include <dirent.h>
|
|
|
|
int
|
|
main(void)
|
|
{
|
|
struct dirent **namelist;
|
|
int n;
|
|
|
|
n = scandir(".", &namelist, NULL, alphasort);
|
|
if (n < 0)
|
|
perror("scandir");
|
|
else {
|
|
while (n\-\-) {
|
|
printf("%s\en", namelist[n]\->d_name);
|
|
free(namelist[n]);
|
|
}
|
|
free(namelist);
|
|
}
|
|
}
|
|
.fi
|
|
.SH "SEE ALSO"
|
|
.BR closedir (3),
|
|
.BR fnmatch (3),
|
|
.BR opendir (3),
|
|
.BR readdir (3),
|
|
.BR rewinddir (3),
|
|
.BR scandirat (3),
|
|
.BR seekdir (3),
|
|
.BR strcmp (3),
|
|
.BR strcoll (3),
|
|
.BR strverscmp (3),
|
|
.BR telldir (3)
|