104 lines
3 KiB
HTML
104 lines
3 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_open</title>
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</head>
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<body>
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<div class="para">
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<h2>pf_open</h2>
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<p>The pf_open function opens an existing file.</p>
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<pre>
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FRESULT pf_open (
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const char* <span class="arg">path</span> <span class="c">/* [IN] Pointer to the file neme */</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>path</dt>
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<dd>Pointer to a null-terminated string that specifies the <a href="filename.html">file name</a> to open.</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_NO_FILE</dt>
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<dd>Could not find the file or path.</dd>
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<dt>FR_DISK_ERR</dt>
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<dd>The function failed due to a hard error in the disk function, a wrong FAT structure or an internal error.</dd>
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<dt>FR_NOT_ENABLED</dt>
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<dd>The volume has not been mounted.</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 file must be opend prior to use <tt>pf_read()</tt> and <tt>pf_lseek()</tt> function. The open file is valid until next open.</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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int main (void)
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{
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FATFS fs; <span class="c">/* Work area (file system object) for the volume */</span>
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BYTE buff[16]; <span class="c">/* File read buffer */</span>
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UINT br; <span class="c">/* File read count */</span>
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FRESULT res; <span class="c">/* Petit FatFs function common result code */</span>
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<span class="c">/* Mount the volume */</span>
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pf_mount(&fs);
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if (res) die(res);
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<span class="c">/* Open a file */</span>
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res = pf_open("srcfile.dat");
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if (res) die(res);
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<span class="c">/* Read data to the memory */</span>
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res = pf_read(buff, 16, &br); <span class="c">/* Read data to the buff[] */</span>
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if (res) die(res); <span class="c">/* Check error */</span>
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if (br != 16) die(255); <span class="c">/* Check EOF */</span>
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....
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<span class="c">/* Forward data to the outgoing stream */</span>
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do
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res = pf_read(0, 512, &br); <span class="c">/* Send data to the stream */</span>
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while (res || br != 512); <span class="c">/* Break on error or eof */</span>
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....
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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>QuickInfo</h4>
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<p>Always available.</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="read.html">pf_read</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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