void set_row_span_column(int row_span);

row_span: A column in the model passed during construction.

The set_row_span_column() method sets the "row-span-column" property to the value specified by row_span. The "row-span-column" property indicates the column in the associated GtkTreeModel row that contains an integer that indicates how many rows the item should span.

See also: get_row_span_column()