[FreeRTOS+FAT Standard API Reference]
int ff_fclose( FF_FILE *pxStream );;
Flushes then closes a file within the embedded FAT file system. The file must have previously been opened using ff_fopen().
A pointer to the file being closed. This will be the
same pointer returned by ff_fopen() when the file was
If the file was closed successfully then 0 is returned.
The example provided on the ff_fopen() documentation page shows how ff_fclose() is used.