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), curs_getch(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.
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