def File(name, dbm_module=None):
    """
    Arrange for all signatures to be stored in a global .sconsign.db*
    file.
    """
    global ForDirectory, DB_Name, DB_Module
    if name is None:
        ForDirectory = DirFile
        DB_Module = None
    else:
        ForDirectory = DB
        DB_Name = name
        if not dbm_module is None:
            DB_Module = dbm_module