INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE ALL FILES FOR GIVEN COMPUTER
        AX = 5D03h
        DS:DX -> DOS parameter list (see AX=5D00h), only computer ID used
Return: CF set on error
            AX = error code (see AH=59h)
        CF clear if successful
Note:   error unless SHARE is loaded (calls [SysFileTable-30h]) (see AH=52h)
SeeAlso: AX=5D04h