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| <h4 class="subsection">14.2.1 Format of a Directory Entry</h4> |
| |
| <p><a name="index-dirent_002eh-1400"></a>This section describes what you find in a single directory entry, as you |
| might obtain it from a directory stream. All the symbols are declared |
| in the header file <samp><span class="file">dirent.h</span></samp>. |
| |
| <!-- dirent.h --> |
| <!-- POSIX.1 --> |
| <div class="defun"> |
| — Data Type: <b>struct dirent</b><var><a name="index-struct-dirent-1401"></a></var><br> |
| <blockquote><p>This is a structure type used to return information about directory |
| entries. It contains the following fields: |
| |
| <dl> |
| <dt><code>char d_name[]</code><dd>This is the null-terminated file name component. This is the only |
| field you can count on in all POSIX systems. |
| |
| <br><dt><code>ino_t d_fileno</code><dd>This is the file serial number. For BSD compatibility, you can also |
| refer to this member as <code>d_ino</code>. In the GNU system and most POSIX |
| systems, for most files this the same as the <code>st_ino</code> member that |
| <code>stat</code> will return for the file. See <a href="File-Attributes.html#File-Attributes">File Attributes</a>. |
| |
| <br><dt><code>unsigned char d_namlen</code><dd>This is the length of the file name, not including the terminating null |
| character. Its type is <code>unsigned char</code> because that is the integer |
| type of the appropriate size |
| |
| <br><dt><code>unsigned char d_type</code><dd>This is the type of the file, possibly unknown. The following constants |
| are defined for its value: |
| |
| <dl> |
| <dt><code>DT_UNKNOWN</code><a name="index-DT_005fUNKNOWN-1402"></a><dd>The type is unknown. On some systems this is the only value returned. |
| |
| <br><dt><code>DT_REG</code><a name="index-DT_005fREG-1403"></a><dd>A regular file. |
| |
| <br><dt><code>DT_DIR</code><a name="index-DT_005fDIR-1404"></a><dd>A directory. |
| |
| <br><dt><code>DT_FIFO</code><a name="index-DT_005fFIFO-1405"></a><dd>A named pipe, or FIFO. See <a href="FIFO-Special-Files.html#FIFO-Special-Files">FIFO Special Files</a>. |
| |
| <br><dt><code>DT_SOCK</code><a name="index-DT_005fSOCK-1406"></a><dd>A local-domain socket. <!-- !!! @xref{Local Domain}. --> |
| |
| <br><dt><code>DT_CHR</code><a name="index-DT_005fCHR-1407"></a><dd>A character device. |
| |
| <br><dt><code>DT_BLK</code><a name="index-DT_005fBLK-1408"></a><dd>A block device. |
| </dl> |
| |
| <p>This member is a BSD extension. The symbol <code>_DIRENT_HAVE_D_TYPE</code> |
| is defined if this member is available. On systems where it is used, it |
| corresponds to the file type bits in the <code>st_mode</code> member of |
| <code>struct statbuf</code>. If the value cannot be determine the member |
| value is DT_UNKNOWN. These two macros convert between <code>d_type</code> |
| values and <code>st_mode</code> values: |
| |
| <!-- dirent.h --> |
| <!-- BSD --> |
| <div class="defun"> |
| — Function: int <b>IFTODT</b> (<var>mode_t mode</var>)<var><a name="index-IFTODT-1409"></a></var><br> |
| <blockquote> <p>This returns the <code>d_type</code> value corresponding to <var>mode</var>. |
| </p></blockquote></div> |
| |
| <!-- dirent.h --> |
| <!-- BSD --> |
| <div class="defun"> |
| — Function: mode_t <b>DTTOIF</b> (<var>int dtype</var>)<var><a name="index-DTTOIF-1410"></a></var><br> |
| <blockquote> <p>This returns the <code>st_mode</code> value corresponding to <var>dtype</var>. |
| </p></blockquote></div> |
| </dl> |
| |
| <p>This structure may contain additional members in the future. Their |
| availability is always announced in the compilation environment by a |
| macro names <code>_DIRENT_HAVE_D_</code><var>xxx</var> where <var>xxx</var> is replaced |
| by the name of the new member. For instance, the member <code>d_reclen</code> |
| available on some systems is announced through the macro |
| <code>_DIRENT_HAVE_D_RECLEN</code>. |
| |
| <p>When a file has multiple names, each name has its own directory entry. |
| The only way you can tell that the directory entries belong to a |
| single file is that they have the same value for the <code>d_fileno</code> |
| field. |
| |
| <p>File attributes such as size, modification times etc., are part of the |
| file itself, not of any particular directory entry. See <a href="File-Attributes.html#File-Attributes">File Attributes</a>. |
| </p></blockquote></div> |
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