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FatFs R0.13c, released October 14, 2018

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Christopher Williams
2019-01-09 17:13:03 -07:00
parent ff793da7d3
commit f2bf030bfd
29 changed files with 361 additions and 257 deletions
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documents/doc/sync.html
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@@ -44,7 +44,30 @@ FRESULT f_sync (
<div class="para desc">
<h4>Description</h4>
<p>The <tt>f_sync</tt> function performs the same process as <tt>f_close</tt> function but the file is left opened and can continue read/write/seek operations to the file. This is suitable for the applications that open files for a long time in write mode, such as data logger. Performing <tt>f_sync</tt> function of periodic or immediataly after <tt>f_write</tt> function can minimize the risk of data loss due to a sudden blackout or an unintentional media removal. For more information, refer to <a href="appnote.html#critical">application note</a>.</p>
<p>The <tt>f_sync</tt> function performs the same process as <tt>f_close</tt> function but the file is left opened and can continue read/write/seek operations to the file. This is suitable for the applications that open files for a long time in write mode, such as data logger. Performing <tt>f_sync</tt> function in certain interval can minimize the risk of data loss due to a sudden blackout or an unintentional media removal. For more information, refer to <a href="appnote.html#critical">application note</a>.</p>
<pre>
Case 1. Normal write sequence
Time --&gt; ↓Power off after close
OwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwC
Case 2. Without using f_sync()
Time --&gt; ↓System crush
O<span class="e">wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww</span>
|&lt;--------------- All data written will be lost ------------------&gt;|
Case 3. Using f_sync()
Time --&gt; ↓System crush
OwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwwwwwwS<span class="e">wwwww</span>
Data after last f_sync will be lost |&lt;-&gt;|
O - f_open()
C - f_close()
w - f_write()
S - f_sync()
</pre>
<p>However there is no sense in <tt>f_sync</tt> function immediataly before <tt>f_close</tt> function because it performs <tt>f_sync</tt> function in it. In other words, the differnce between those functions is that the file object is invalidated or not.</p>
</div>