menu_driver (3) ( Linux man: Библиотечные вызовы )
NAME
menu_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 is 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.
MOUSE HANDLING
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 for a single click,
a REQ_SCR_UPAGE is generated for a double-click and
a REQ_FIRST_ITEM is generated for a triple-click.
If you click below the display region of the menu:
a REQ_SCR_DLINE is generated for a single click,
a REQ_SCR_DPAGE is generated for a double-click and
a REQ_LAST_ITEM is generated for a triple-click.
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 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 is 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.
APPLICATION-DEFINED COMMANDS
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.
RETURN VALUE
menu_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.
The header file <menu.h> automatically includes the header files
<curses.h>.
PORTABILITY
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.
AUTHORS
Juergen Pfeifer. Manual pages and adaptation for new curses by Eric
S. Raymond.
