X-Git-Url: http://cloudbase.mooo.com/gitweb/z180-stamp.git/blobdiff_plain/0f3b947bda5f34662a611272b9f12199e0da9aca..64db7d7a152ab5677faf83a4ea8370019993b1b5:/fatfs/documents/doc/sync.html?ds=sidebyside diff --git a/fatfs/documents/doc/sync.html b/fatfs/documents/doc/sync.html index a0317d6..9fb42a0 100644 --- a/fatfs/documents/doc/sync.html +++ b/fatfs/documents/doc/sync.html @@ -44,7 +44,30 @@ FRESULT f_sync (
The f_sync function performs the same process as f_close 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 f_sync function of periodic or immediataly after f_write function can minimize the risk of data loss due to a sudden blackout or an unintentional media removal. For more information, refer to application note.
+The f_sync function performs the same process as f_close 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 f_sync 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 application note.
++Case 1. Normal write sequence + + Time --> âNormal shutdown +OwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwC <Power off> + + +Case 2. Without using f_sync() + + Time --> âSystem crush +Owwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww + |<--------------- All data written will be lost ------------------>| + + +Case 3. Using f_sync() + Time --> âSystem crush +OwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwwwwwwSwwwww + Data after last f_sync will be lost |<->| +O - f_open() +C - f_close() +w - f_write() +S - f_sync() +
However there is no sense in f_sync function immediataly before f_close function because it performs f_sync function in it. In other words, the differnce between those functions is that the file object is invalidated or not.