dirent.h(0P) POSIX Programmer's Manual dirent.h(0P)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.
NAMEdirent.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 fol‐
lowing 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 imple‐
mentations 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 com‐
pletely 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 Electri‐
cal 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.ker‐
nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 dirent.h(0P)
