- If the second argument is a printable ASCII character, the
- code appends it to the pattern buffer and attempts to move
- to the next item matching the new pattern. If there is no
- such match, <B>menu_driver</B> returns <B>E_NO_MATCH</B> and deletes the
- appended character from the buffer.
-
- If the second argument is one of the above pre-defined
- requests, the corresponding action is performed.
-
- If the second argument is the KEY_MOUSE special key, the
- associated mouse event is translated into one of the above
- pre-defined requests. Currently only clicks in the user
- window (e.g. inside the menu display area or the decora-
- tion window) are handled. If you click above the display
- region of the menu, a REQ_SCR_ULINE is generated, if you
- doubleclick a REQ_SCR_UPAGE is generated and if you
- tripleclick a REQ_FIRST_ITEM is generated. If you click
- below the display region of the menu, a REQ_SCR_DLINE is
- generated, if you doubleclick a REQ_SCR_DPAGE is generated
- and if you tripleclick a REQ_LAST_ITEM is generated. If
- you click at an item inside the display area of the menu,
- the menu cursor is positioned to that item. If you double-
- click at an item a REQ_TOGGLE_ITEM is generated and
- <B>E_UNKNOWN_COMMAND</B> is returned. This return value makes
- sense, because a double click usually means that an item-
- specific action should be returned. It's exactly the pur-
- pose of this return value to signal that an application
- specific command should be executed. If a translation into
- a request was done, <B>menu_driver</B> returns the result of this
- request. If you clicked outside the user window or the
- mouse event couldn't be translated into a menu request an
- <B>E_REQUEST_DENIED</B> is returned.
-
- If the second argument is neither printable ASCII nor one
- of the above pre-defined menu requests or KEY_MOUSE, the
- drive assumes it is an application-specific command and
- returns <B>E_UNKNOWN_COMMAND</B>. Application-defined commands
- should be defined relative to <B>MAX_COMMAND</B>, the maximum
- value of these pre-defined requests.