fatfs/doc/en/readdir.html

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   9 <title>FatFs - f_readdir</title>
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  13
  14 <div class="para func">
  15 <h2>f_readdir</h2>
  16 <p>The f_readdir function reads directory entries.</p>
  17 <pre>
  18 FRESULT f_readdir (
  19   DIR* <span class="arg">dp</span>,      <span class="c">/* [IN] Directory object */</span>
  20   FILINFO* <span class="arg">fno</span>  <span class="c">/* [OUT] File information structure */</span>
  21 );
  22 </pre>
  23 </div>
  24
  25 <div class="para arg">
  26 <h4>Parameters</h4>
  27 <dl class="par">
  28 <dt>dp</dt>
  29 <dd>Pointer to the open directory object.</dd>
  30 <dt>fno</dt>
  31 <dd>Pointer to the file information structure to store the read item.</dd>
  32 </dl>
  33 </div>
  34
  35
  36 <div class="para ret">
  37 <h4>Return Values</h4>
  38 <p>
  39 <a href="rc.html#ok">FR_OK</a>,
  40 <a href="rc.html#de">FR_DISK_ERR</a>,
  41 <a href="rc.html#ie">FR_INT_ERR</a>,
  42 <a href="rc.html#nr">FR_NOT_READY</a>,
  43 <a href="rc.html#io">FR_INVALID_OBJECT</a>,
  44 <a href="rc.html#tm">FR_TIMEOUT</a>,
  45 <a href="rc.html#nc">FR_NOT_ENOUGH_CORE</a>
  46 </p>
  47 </div>
  48
  49
  50 <div class="para desc">
  51 <h4>Description</h4>
  52 <p>The <tt>f_readdir()</tt> function reads directory items, file and directory, in sequence. All items in the directory can be read by calling <tt>f_readdir()</tt> function repeatedly. When relative path feature is enabled (<tt>_FS_RPATH &gt;= 1</tt>), dot entries ("." and "..") are not filtered out and they will appear in the read items. When all directory items have been read and no item to read, a null string is returned into the <tt>fname[]</tt> without any error. When a null pointer is given to the <tt class="arg">fno</tt>, the read index of the directory object is rewinded.</p>
  53 <p>When LFN feature is enabled, <tt>lfname</tt> and <tt>lfsize</tt> in the file information structure must be initialized with valid value prior to use it. The <tt>lfname</tt> is a pointer to the LFN read buffer. The <tt>lfsize</tt> is size of the LFN read buffer in unit of <tt>TCHAR</tt>. If the LFN is not needed, set a null pointer to the <tt>lfname</tt> and the LFN is not returned. A null string will be returned into the LFN read buffer in case of following conditions.</p>
  54 <ul>
  55 <li>The directory item has no LFN information.</li>
  56 <li>Either the size of read buffer or LFN working buffer is insufficient for the LFN.</li>
  57 <li>The LFN contains any Unicode character that cannot be converted to OEM code. (not the case at Unicode API cfg.)</li>
  58 </ul>
  59 <p>When the directory item has no LFN information, lower case characters can be contained in the <tt>fname[]</tt>.</p>
  60 </div>
  61
  62
  63 <div class="para comp">
  64 <h4>QuickInfo</h4>
  65 <p>Available when <tt>_FS_MINIMIZE &lt;= 1</tt>.</p>
  66 </div>
  67
  68
  69 <div class="para use">
  70 <h4>Sample Code</h4>
  71 <pre>
  72 FRESULT scan_files (
  73     char* path        <span class="c">/* Start node to be scanned (also used as work area) */</span>
  74 )
  75 {
  76     FRESULT res;
  77     FILINFO fno;
  78     DIR dir;
  79     int i;
  80     char *fn;   <span class="c">/* This function assumes non-Unicode configuration */</span>
  81 <span class="k">#if</span> _USE_LFN
  82     static char lfn[_MAX_LFN + 1];   <span class="c">/* Buffer to store the LFN */</span>
  83     fno.lfname = lfn;
  84     fno.lfsize = sizeof lfn;
  85 <span class="k">#endif</span>
  86
  87
  88     res = f_opendir(&amp;dir, path);                       <span class="c">/* Open the directory */</span>
  89     if (res == FR_OK) {
  90         i = strlen(path);
  91         for (;;) {
  92             res = f_readdir(&amp;dir, &amp;fno);                   <span class="c">/* Read a directory item */</span>
  93             if (res != FR_OK || fno.fname[0] == 0) break;  <span class="c">/* Break on error or end of dir */</span>
  94             if (fno.fname[0] == '.') continue;             <span class="c">/* Ignore dot entry */</span>
  95 <span class="k">#if</span> _USE_LFN
  96             fn = *fno.lfname ? fno.lfname : fno.fname;
  97 <span class="k">#else</span>
  98             fn = fno.fname;
  99 <span class="k">#endif</span>
 100             if (fno.fattrib &amp; AM_DIR) {                    <span class="c">/* It is a directory */</span>
 101                 sprintf(&amp;path[i], "/%s", fn);
 102                 res = scan_files(path);
 103                 path[i] = 0;
 104                 if (res != FR_OK) break;
 105             } else {                                       <span class="c">/* It is a file. */</span>
 106                 printf("%s/%s\n", path, fn);
 107             }
 108         }
 109         f_closedir(&amp;dir)
 110     }
 111
 112     return res;
 113 }
 114 </pre>
 115 </div>
 116
 117
 118 <div class="para ref">
 119 <h4>See Also</h4>
 120 <p><tt><a href="opendir.html">f_opendir</a>, <a href="closedir.html">f_closedir</a>, <a href="stat.html">f_stat</a>, <a href="sfileinfo.html">FILINFO</a>, <a href="sdir.html">DIR</a></tt></p>
 121 </div>
 122
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