Once a menu has been posted (displayed), you should funnel input events to it through menu-driver. This routine has three major input cases:
The menu driver request are as follows.
Move left to an item.
Move right to an item.
Move up to an item.
Move down to an item.
Scroll up a line.
Scroll down a line.
Scroll down a page.
Scroll up a page.
Move to the first item.
Move to the last item.
Move to the next item.
Move to the previous item.
Select/deselect an item.
Clear the menu pattern buffer.
Delete the previous character from the pattern buffer.
Move to the next item matching the pattern match.
Move to the previous item matching the pattern match.
If the second argument c is a printable 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, menu-driver
E_NO_MATCH and deletes the appended character from the
If the second argument c 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 decoration window) are handled.
If you click above the display region of the menu:
If you click below the display region of the menu:
If you click at an item inside the display area of the menu:
REQ_TOGGLE_ITEMis generated and
E_UNKNOWN_COMMANDis returned. This return value makes sense, because a double click usually means that an item-specific action should be returned. It is exactly the purpose of this return value to signal that an application specific command should be executed.
If you clicked outside the user window or the mouse event could not be translated into a menu request an E_REQUEST_DENIED is returned.
menu-driver returns one of the following error codes:
The routine succeeded.
System error occurred (see errno).
Routine detected an incorrect or out-of-range argument.
Routine was called from an initialization or termination function.
The menu has not been posted.
The menu driver code saw an unknown request code.
Character failed to match.
The menu driver could not process the request.