driver(3MENU)															     driver(3MENU)

NAME

       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:

       -  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.

       -  The input is a printable character.  Printable characters (which must be positive, less than 256) are checked according to the program's
	  locale settings.

       -  The input 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 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 could not be translated into a menu request an E_REQUEST_DENIED is returned.

   APPLICATION-DEFINED COMMANDS
       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  appli-
       cation-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.

       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 ALSO

       ncurses(3NCURSES), menu(3MENU), wgetch(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 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.

																     driver(3MENU)