menu_driver(3X)menu_driver(3X)NAMEmenu_driver - command-processing loop of the menu system
SYNOPSIS
#include <menu.h>
int menu_driver(MENU *menu, int c);
DESCRIPTION
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:
REQ_LEFT_ITEM
Move left to an item.
REQ_RIGHT_ITEM
Move right to an item.
REQ_UP_ITEM
Move up to an item.
REQ_DOWN_ITEM
Move down to an item.
REQ_SCR_ULINE
Scroll up a line.
REQ_SCR_DLINE
Scroll down a line.
REQ_SCR_DPAGE
Scroll down a page.
REQ_SCR_UPAGE
Scroll up a page.
REQ_FIRST_ITEM
Move to the first item.
REQ_LAST_ITEM
Move to the last item.
REQ_NEXT_ITEM
Move to the next item.
REQ_PREV_ITEM
Move to the previous item.
REQ_TOGGLE_ITEM
Select/deselect an item.
REQ_CLEAR_PATTERN
Clear the menu pattern buffer.
REQ_BACK_PATTERN
Delete the previous character from the pattern buffer.
REQ_NEXT_MATCH
Move to the next item matching the pattern match.
REQ_PREV_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 dis‐
play region of the menu, a REQ_SCR_ULINE is generated, if you dou‐
bleclick 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 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's exactly the pur‐
pose of this return value to signal that an application specific com‐
mand 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. Applica‐
tion-defined commands should be defined relative to MAX_COMMAND, the
maximum value of these pre-defined requests.
RETURN VALUEmenu_driver return one of the following error codes:
E_OK The routine succeeded.
E_SYSTEM_ERROR
System error occurred (see errno).
E_BAD_ARGUMENT
Routine detected an incorrect or out-of-range argument.
E_BAD_STATE
Routine was called from an initialization or termination function.
E_NOT_POSTED
The menu has not been posted.
E_UNKNOWN_COMMAND
The menu driver code saw an unknown request code.
E_NO_MATCH
Character failed to match.
E_REQUEST_DENIED
The menu driver could not process the request.
SEE ALSOcurses(3X), menu(3X).
NOTES
The header file <menu.h> automatically includes the header files
<curses.h>.
PORTABILITY
These routines emulate the System V menu library. They were not sup‐
ported on Version 7 or BSD versions. The support for mouse events is
ncurses specific.
AUTHORS
Juergen Pfeifer. Manual pages and adaptation for new curses by Eric S.
Raymond.
menu_driver(3X)