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PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface
may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface
may not be implemented on Linux.
NAME
dirent.h — format of directory entries
SYNOPSIS
#include <dirent.h>
DESCRIPTION
The internal format of directories is unspecified.
The <dirent.h> header shall define the following type:
DIR A type representing a directory stream. The DIR type may be an incomplete type.
It shall also define the structure dirent which shall include the following members:
ino_t d_ino File serial number.
char d_name[] Filename string of entry.
The <dirent.h> header shall define the ino_t type as described in <sys/types.h>.
The array d_name is of unspecified size, but shall contain a filename of at most {NAME_MAX} bytes
followed by a terminating null byte.
The following shall be declared as functions and may also be defined as macros. Function prototypes shall
be provided.
int alphasort(const struct dirent **, const struct dirent **);
int closedir(DIR *);
int dirfd(DIR *);
DIR *fdopendir(int);
DIR *opendir(const char *);
struct dirent *readdir(DIR *);
int readdir_r(DIR *restrict, struct dirent *restrict,
struct dirent **restrict);
void rewinddir(DIR *);
int scandir(const char *, struct dirent ***,
int (*)(const struct dirent *),
int (*)(const struct dirent **,
const struct dirent **));
void seekdir(DIR *, long);
long telldir(DIR *);
The following sections are informative.
APPLICATION USAGE
None.
RATIONALE
Information similar to that in the <dirent.h> header is contained in a file <sys/dir.h> in 4.2 BSD and
4.3 BSD. The equivalent in these implementations of struct dirent from this volume of POSIX.1‐2008 is
struct direct. The filename was changed because the name <sys/dir.h> was also used in earlier
implementations to refer to definitions related to the older access method; this produced name conflicts.
The name of the structure was changed because this volume of POSIX.1‐2008 does not completely define what
is in the structure, so it could be different on some implementations from struct direct.
The name of an array of char of an unspecified size should not be used as an lvalue. Use of:
sizeof(d_name)
is incorrect; use:
strlen(d_name)
instead.
The array of char d_name is not a fixed size. Implementations may need to declare struct dirent with an
array size for d_name of 1, but the actual number of bytes provided matches (or only slightly exceeds)
the length of the filename string.
FUTURE DIRECTIONS
None.
SEE ALSO
<sys_types.h>
The System Interfaces volume of POSIX.1‐2008, alphasort(), closedir(), dirfd(), fdopendir(), readdir(),
rewinddir(), seekdir(), telldir()
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the event
of any discrepancy between this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at
http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are most likely to have been introduced
during the conversion of the source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .