t>fp</dt>
<dd>Pointer to the open file object.</dd>
<dt>fsz</dt>
<dd>Number of bytes in size to prepare or allocate for the file. The data type <tt>FSIZE_t</tt> is an alias of either <tt>DWORD</tt>(32-bit) or <tt>QWORD</tt>(64-bit) depends on the configuration option <tt>FF_FS_EXFAT</tt>.</dd>
<dt>opt</dt>
<dd>Operation mode. Prepare only (0) or Allocate now (1).</dd>
</dl>
</div>


<div class="para ret">
<h4>Return Values</h4>
<p>
<a href="rc.html#ok">FR_OK</a>,
<a href="rc.html#de">FR_DISK_ERR</a>,
<a hre