80 lines
2.1 KiB
HTML
80 lines
2.1 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
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<html lang="en">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
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<meta http-equiv="Content-Style-Type" content="text/css">
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<link rel="up" title="Petit FatFs" href="../00index_p.html">
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<link rel="stylesheet" href="../css_e.css" type="text/css" media="screen" title="ELM Default">
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<link rel="stylesheet" href="../css_p.css" type="text/css" media="screen" title="ELM Default">
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<title>Petit FatFs - pf_lseek</title>
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</head>
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<body>
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<div class="para">
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<h2>pf_lseek</h2>
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<p>The pf_lseek function moves the file read/write pointer of the open file.</p>
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<pre>
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FRESULT pf_lseek (
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DWORD <span class="arg">ofs</span> <span class="c">/* [IN] File offset in unit of byte */</span>
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);
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</pre>
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</div>
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<div class="para">
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<h4>Parameters</h4>
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<dl class="par">
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<dt>ofs</dt>
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<dd>Number of bytes where from start of the file</dd>
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</dl>
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</div>
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<div class="para">
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<h4>Return Values</h4>
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<dl class="ret">
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<dt>FR_OK (0)</dt>
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<dd>The function succeeded.</dd>
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<dt>FR_DISK_ERR</dt>
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<dd>The function failed due to an error in the disk function, a wrong FAT structure or an internal error.</dd>
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<dt>FR_NOT_OPENED</dt>
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<dd>The file has not been opened.</dd>
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</dl>
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</div>
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<div class="para">
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<h4>Description</h4>
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<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>
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</div>
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<div class="para">
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<h4>Example</h4>
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<pre>
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<span class="c">/* Move to offset of 5000 from top of the file */</span>
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res = pf_lseek(5000);
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<span class="c">/* Forward 3000 bytes */</span>
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res = pf_lseek(fs.fptr + 3000);
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<span class="c">/* Rewind 2000 bytes (take care on wraparound) */</span>
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res = pf_lseek(fs.fptr - 2000);
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</pre>
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</div>
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<div class="para">
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<h4>QuickInfo</h4>
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<p>Available when <tt>_USE_LSEEK == 1</tt>.</p>
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</div>
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<div class="para">
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<h4>References</h4>
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<p><tt><a href="open.html">pf_open</a>, <a href="sfatfs.html">FATFS</a></tt></p>
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</div>
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<p class="foot"><a href="../00index_p.html">Return</a></p>
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</body>
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</html>
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