Synopsis:

       key_value=db_key()

Arguments:

       NONE

Description:    This function returns key at current position in a search. A call to db_first() must have previously been made to set the index pointer. This is useful for finding the current key when db_next() or db_prev() is used with a 0 (false) value for exact_flag. An empty string "" is returned if an error occurs, or if the current search is not positioned on a key value.

Returns:   Returns the key value of the index key currently pointed to by the index pointer (set up through a call to db_first() (then possibly db_next() or db_prev()).    If the index pointer does not point to a key entry in ythe index (either because db_first() hasn't been called or because the index pointer points between records), then the function will return an empty string.