menu_driver - command-processing loop of the menu system
int menu_driver(MENU *menu, int c);
Once a menu has been posted (displayed), you should funnel
input events to it through menu_driver. This routine has
three major input cases:
o The input is a form navigation request. Navigation
request codes are constants defined in <form.h>, which
are distinct from the key- and character codes
returned by wgetch.
o The input is a printable character. Printable charac-
ters (which must be positive, less than 256) are
checked according to the program's locale settings.
o The input is the KEY_MOUSE special key associated with
an mouse event.
The menu driver requests 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 buf-
Move to the next item matching the pattern match.
Move to the previous item matching the pattern match.
If the second argument 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 returns E_NO_MATCH 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:
o a REQ_SCR_ULINE is generated for a single click,
o a REQ_SCR_UPAGE is generated for a double-click and
o a REQ_FIRST_ITEM is generated for a triple-click.
If you click below the display region of the menu:
o a REQ_SCR_DLINE is generated for a single click,
o a REQ_SCR_DPAGE is generated for a double-click and
o a REQ_LAST_ITEM is generated for a triple-click.
If you click at an item inside the display area of the
o the menu cursor is positioned to that item.
o If you double-click an item a REQ_TOGGLE_ITEM is gen-
erated and E_UNKNOWN_COMMAND is 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 sig-
nal that an application specific command should be
o If a translation into a request was done, menu_driver
returns the result of this request.
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.
If the second argument is neither printable nor one of the
above pre-defined menu requests or KEY_MOUSE, the drive
assumes it is an application-specific command and returns
E_UNKNOWN_COMMAND. Application-defined commands should be
defined relative to MAX_COMMAND, the maximum value of
these pre-defined requests.
menu_driver return one of the following error codes:
E_OK The routine succeeded.
System error occurred (see errno).
Routine detected an incorrect or out-of-range argu-
Routine was called from an initialization or termina-
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.
curses(3x), menu(3x), wgetch(3x).
The header file <menu.h> automatically includes the header
These routines emulate the System V menu library. They
were not supported on Version 7 or BSD versions. The sup-
port for mouse events is ncurses specific.
Juergen Pfeifer. Manual pages and adaptation for new
curses by Eric S. Raymond.
Man(1) output converted with