# mfsRamGetFreeDirEntryNum

    Format:	s32 mfsRamGetFreeDirEntryNum(void)
    Arguments:	None
    Return value:Remaining number of files (directories) that can be recorded (a negative value is an error)
    Function:	Obtains number of files (directories) that can be recorded
    Description:	MFS has an upper limit for the number of files (directories) that can be recorded.
    	This upper limit value differs as follows according to the disk type.

    	          +------------+----------------+
    	          | Disk type  | Number of files|
    	          +================+============+
    	          |      0     |       899      |
    	          |      1     |       814      |
    	          |      2     |       729      |
    	          |      3     |       644      |
    	          |      4     |       559      |
    	          |      5     |       474      |
    	          |      6     |        -       |
    	          +------------+----------------+

    	This function obtains the remaining number of files (directories) that can be recorded.  Note that this number of files cannot be exceeded when recording data even if the disk has free space.

    Main errors:
    	MFS_ERR_NOTMFSDISK Not an MFS-format disk
    			The disk ID's disk use is not 1, or the header is different.
    	MFS_ERR_VERSION	Different version disk
    	MFS_ERR_PROTECT	Write protected
    			The medium is volume protected.