If the boolean argument expand is nonzero, and the name matches a cell in the main database, the cell and all of the cells in its hierarchy will be added to the table, otherwise only the named cell will be added. It is not an error to add the same cell more than once, duplicates will be ignored.
If the UseCellTab variable is set, when a Cell Hierarchy Digest (CHD) is used to process a cell hierarchy for anything other than reading cells into the main database, cells listed in the cell table will override cells of the same name in the CHD. Thus, for example, one can substitute modified versions of cells as a layout file is being written.
The return value is 1 if all goes well, 0 if the table is not initialized or the cell is not found.