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; either the input is a menu navigation
request, it's a printable ASCII character or it 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
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 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, 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 decoration
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 doubleclick
at an item a REQ_TOGGLE_ITEM is generated and
E_UNKNOWN_COMMAND is returned. This return value makes
sense, because a double click usually means that an itemspecific
action should be returned. It's exactly the purpose
of this return value to signal that an application
specific command should be executed. 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 couldn't be translated into a menu request an
E_REQUEST_DENIED 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 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.
E_SYSTEM_ERROR [Toc] [Back]
System error occurred (see errno).
E_BAD_ARGUMENT [Toc] [Back]
Routine detected an incorrect or out-of-range argument.
E_BAD_STATE [Toc] [Back]
Routine was called from an initialization or termination
E_NOT_POSTED [Toc] [Back]
The menu has not been posted.
E_UNKNOWN_COMMAND [Toc] [Back]
The menu driver code saw an unknown request code.
E_NO_MATCH [Toc] [Back]
Character failed to match.
E_REQUEST_DENIED [Toc] [Back]
The menu driver could not process the request.
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 support
for mouse events is ncurses specific.
Juergen Pfeifer. Manual pages and adaptation for new
curses by Eric S. Raymond.
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