dirent.h(3)                POSIX Programmer's Manual               dirent.h(3)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

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.1-2017 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.1-2017
       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.1-2017, alphasort(), closedir(),
       dirfd(), fdopendir(), readdir(), rewinddir(), seekdir(), telldir()

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  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.opengroup.org/unix/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 .



IEEE/The Open Group                  2017                          dirent.h(3)
