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menu_driver 3x



menu_driver(3x)                                         menu_driver(3x)




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:

       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:

       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 buf-
            fer.

       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  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
       menu:

       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
           executed.

       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.

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 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  argu-
            ment.

       E_BAD_STATE
            Routine was called from an initialization or termina-
            tion 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

       curses(3x), menu(3x), curs_getch(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  sup-
       port for mouse events is ncurses specific.


AUTHORS

       Juergen  Pfeifer.   Manual  pages  and  adaptation for new
       curses by Eric S. Raymond.



                                                        menu_driver(3x)

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