1e6865dcdSopenharmony_ci<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> 2e6865dcdSopenharmony_ci<html lang="en"> 3e6865dcdSopenharmony_ci<head> 4e6865dcdSopenharmony_ci<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 5e6865dcdSopenharmony_ci<meta http-equiv="Content-Style-Type" content="text/css"> 6e6865dcdSopenharmony_ci<link rel="up" title="FatFs" href="../00index_e.html"> 7e6865dcdSopenharmony_ci<link rel="alternate" hreflang="ja" title="Japanese" href="../ja/sync.html"> 8e6865dcdSopenharmony_ci<link rel="stylesheet" href="../css_e.css" type="text/css" media="screen" title="ELM Default"> 9e6865dcdSopenharmony_ci<title>FatFs - f_sync</title> 10e6865dcdSopenharmony_ci</head> 11e6865dcdSopenharmony_ci 12e6865dcdSopenharmony_ci<body> 13e6865dcdSopenharmony_ci 14e6865dcdSopenharmony_ci<div class="para func"> 15e6865dcdSopenharmony_ci<h2>f_sync</h2> 16e6865dcdSopenharmony_ci<p>The f_sync function flushes the cached information of a writing file.</p> 17e6865dcdSopenharmony_ci<pre> 18e6865dcdSopenharmony_ciFRESULT f_sync ( 19e6865dcdSopenharmony_ci FIL* <span class="arg">fp</span> <span class="c">/* [IN] File object */</span> 20e6865dcdSopenharmony_ci); 21e6865dcdSopenharmony_ci</pre> 22e6865dcdSopenharmony_ci</div> 23e6865dcdSopenharmony_ci 24e6865dcdSopenharmony_ci<div class="para arg"> 25e6865dcdSopenharmony_ci<h4>Parameter</h4> 26e6865dcdSopenharmony_ci<dl class="par"> 27e6865dcdSopenharmony_ci<dt>fp</dt> 28e6865dcdSopenharmony_ci<dd>Pointer to the open file object to be flushed.</dd> 29e6865dcdSopenharmony_ci</dl> 30e6865dcdSopenharmony_ci</div> 31e6865dcdSopenharmony_ci 32e6865dcdSopenharmony_ci 33e6865dcdSopenharmony_ci<div class="para ret"> 34e6865dcdSopenharmony_ci<h4>Return Values</h4> 35e6865dcdSopenharmony_ci<p> 36e6865dcdSopenharmony_ci<a href="rc.html#ok">FR_OK</a>, 37e6865dcdSopenharmony_ci<a href="rc.html#de">FR_DISK_ERR</a>, 38e6865dcdSopenharmony_ci<a href="rc.html#ie">FR_INT_ERR</a>, 39e6865dcdSopenharmony_ci<a href="rc.html#io">FR_INVALID_OBJECT</a>, 40e6865dcdSopenharmony_ci<a href="rc.html#tm">FR_TIMEOUT</a> 41e6865dcdSopenharmony_ci</p> 42e6865dcdSopenharmony_ci</div> 43e6865dcdSopenharmony_ci 44e6865dcdSopenharmony_ci 45e6865dcdSopenharmony_ci<div class="para desc"> 46e6865dcdSopenharmony_ci<h4>Description</h4> 47e6865dcdSopenharmony_ci<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, wrong media removal or unrecoverable disk error. For more information, refer to <a href="appnote.html#critical">application note</a>.</p> 48e6865dcdSopenharmony_ci<pre> 49e6865dcdSopenharmony_ciCase 1. Normal write sequence 50e6865dcdSopenharmony_ci 51e6865dcdSopenharmony_ci Time --> ↓Normal shutdown 52e6865dcdSopenharmony_ciOwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwC <Power off> 53e6865dcdSopenharmony_ci 54e6865dcdSopenharmony_ci 55e6865dcdSopenharmony_ciCase 2. Without using f_sync() 56e6865dcdSopenharmony_ci 57e6865dcdSopenharmony_ci Time --> ↓System crush 58e6865dcdSopenharmony_ciO<span class="e">wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww</span> 59e6865dcdSopenharmony_ci |<--------------- All data written will be lost ------------------>| 60e6865dcdSopenharmony_ci 61e6865dcdSopenharmony_ci 62e6865dcdSopenharmony_ciCase 3. Using f_sync() 63e6865dcdSopenharmony_ci Time --> ↓System crush 64e6865dcdSopenharmony_ciOwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwwwwwwS<span class="e">wwwww</span> 65e6865dcdSopenharmony_ci Data after last f_sync will be lost |<->| 66e6865dcdSopenharmony_ciO - f_open() 67e6865dcdSopenharmony_ciC - f_close() 68e6865dcdSopenharmony_ciw - f_write() 69e6865dcdSopenharmony_ciS - f_sync() 70e6865dcdSopenharmony_ci</pre> 71e6865dcdSopenharmony_ci<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> 72e6865dcdSopenharmony_ci</div> 73e6865dcdSopenharmony_ci 74e6865dcdSopenharmony_ci 75e6865dcdSopenharmony_ci<div class="para comp"> 76e6865dcdSopenharmony_ci<h4>QuickInfo</h4> 77e6865dcdSopenharmony_ci<p>Available when <tt><a href="config.html#fs_readonly">FF_FS_READONLY</a> == 0</tt>.</p> 78e6865dcdSopenharmony_ci</div> 79e6865dcdSopenharmony_ci 80e6865dcdSopenharmony_ci 81e6865dcdSopenharmony_ci<div class="para ref"> 82e6865dcdSopenharmony_ci<h4>See Also</h4> 83e6865dcdSopenharmony_ci<p><tt><a href="close.html">f_close</a></tt>, <a href="appnote.html#critical">Critical section</a></p> 84e6865dcdSopenharmony_ci</div> 85e6865dcdSopenharmony_ci 86e6865dcdSopenharmony_ci<p class="foot"><a href="../00index_e.html">Return</a></p> 87e6865dcdSopenharmony_ci</body> 88e6865dcdSopenharmony_ci</html> 89