mirror of https://github.com/mkerrisk/man-pages
111 lines
3.1 KiB
Groff
111 lines
3.1 KiB
Groff
.\" Copyright (C) 1993 David Metcalfe (david@prism.demon.co.uk)
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.\" References consulted:
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.\" Linux libc source code
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.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
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.\" 386BSD man pages
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.\" Modified Sat Jul 24 16:09:49 1993 by Rik Faith (faith@cs.unc.edu)
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.\" Modified 11 June 1995 by Andries Brouwer (aeb@cwi.nl)
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.\" Modified 22 July 1996 by Andries Brouwer (aeb@cwi.nl)
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.\"
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.TH READDIR 3 1996-04-22 "" "Linux Programmer's Manual"
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.SH NAME
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readdir \- read a directory
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.SH SYNOPSIS
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.nf
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.B #include <sys/types.h>
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.sp
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.B #include <dirent.h>
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.sp
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.BI "struct dirent *readdir(DIR *" dir );
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.fi
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.SH DESCRIPTION
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The
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.BR readdir ()
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function returns a pointer to a \fIdirent\fP structure
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representing the next directory entry in the directory stream pointed
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to by \fIdir\fP.
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It returns NULL on reaching the end-of-file or if
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an error occurred.
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.PP
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On Linux, the
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.I dirent
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structure is defined as follows:
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.PP
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.RS 0.25i
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.nf
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struct dirent {
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ino_t d_ino; /* inode number */
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off_t d_off; /* offset to the next dirent */
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unsigned short d_reclen; /* length of this record */
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unsigned char d_type; /* type of file */
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char d_name[256]; /* filename */
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};
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.fi
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.RE
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.PP
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According to POSIX, the
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.I dirent
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structure contains a field
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.I "char d_name[]"
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of unspecified size, with at most
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.B NAME_MAX
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characters preceding the terminating null byte.
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POSIX.1-2001 also documents the field
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.I "ino_t d_ino"
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as an XSI extension.
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.IR "Use of other fields will harm the portability of your programs" .
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.PP
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The data returned by
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.BR readdir ()
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may be overwritten by subsequent
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calls to
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.BR readdir ()
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for the same directory stream.
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.SH "RETURN VALUE"
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The
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.BR readdir ()
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function returns a pointer to a
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.I dirent
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structure, or
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NULL if an error occurs or end-of-file is reached.
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On error,
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.I errno
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is set appropriately.
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.SH ERRORS
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.TP
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.B EBADF
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Invalid directory stream descriptor \fIdir\fP.
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.SH "CONFORMING TO"
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SVr4, 4.3BSD, POSIX.1-2001
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.SH "SEE ALSO"
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.BR read (2),
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.BR closedir (3),
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.BR dirfd (3),
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.BR ftw (3),
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.BR opendir (3),
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.BR rewinddir (3),
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.BR scandir (3),
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.BR seekdir (3),
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.BR telldir (3)
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