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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
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<link rel="up" title="Petit FatFs" href="../00index_p.html">
<link rel="stylesheet" href="../css_e.css" type="text/css" media="screen" title="ELM Default">
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<title>Petit FatFs - pf_lseek</title>
</head>
<body>
<div class="para">
<h2>pf_lseek</h2>
<p>The pf_lseek function moves the file read/write pointer of the open file.</p>
<pre>
FRESULT pf_lseek (
DWORD <span class="arg">ofs</span> <span class="c">/* [IN] File offset in unit of byte */</span>
);
</pre>
</div>
<div class="para">
<h4>Parameters</h4>
<dl class="par">
<dt>ofs</dt>
<dd>Number of bytes where from start of the file</dd>
</dl>
</div>
<div class="para">
<h4>Return Values</h4>
<dl class="ret">
<dt>FR_OK (0)</dt>
<dd>The function succeeded.</dd>
<dt>FR_DISK_ERR</dt>
<dd>The function failed due to an error in the disk function, a wrong FAT structure or an internal error.</dd>
<dt>FR_NOT_OPENED</dt>
<dd>The file has not been opened.</dd>
</dl>
</div>
<div class="para">
<h4>Description</h4>
<p>The <tt>pf_lseek()</tt> function moves the file read/write pointer of the open file. The <tt class="arg">offset</tt> can be specified in only origin from top of the file.</p>
</div>
<div class="para">
<h4>Example</h4>
<pre>
<span class="c">/* Move to offset of 5000 from top of the file */</span>
res = pf_lseek(5000);
<span class="c">/* Forward 3000 bytes */</span>
res = pf_lseek(fs.fptr + 3000);
<span class="c">/* Rewind 2000 bytes (take care on wraparound) */</span>
res = pf_lseek(fs.fptr - 2000);
</pre>
</div>
<div class="para">
<h4>QuickInfo</h4>
<p>Available when <tt>_USE_LSEEK == 1</tt>.</p>
</div>
<div class="para">
<h4>References</h4>
<p><tt><a href="open.html">pf_open</a>, <a href="sfatfs.html">FATFS</a></tt></p>
</div>
<p class="foot"><a href="../00index_p.html">Return</a></p>
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