This function returns 1 (true) if the content of the paste buffer name represents a single table for the current document. If name is the empty string, the default paste buffer is assumed.

If buffer_is_table returns 1, $gridId is set to the TOId (table object identifier) for the grid.

If external is omitted or 0, the system clipboard is not checked. If external is not 0, the content of the system clipboard is checked to see if it represents the markup of a single table for the current document.