NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO | NOTES | PORTABILITY | AUTHORS | COLOPHON

menu_driver(3X)                                              menu_driver(3X)

NAME         top

       menu_driver - command-processing loop of the menu system

SYNOPSIS         top

       #include <menu.h>
       int menu_driver(MENU *menu, int c);

DESCRIPTION         top

       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(3X).

       ·   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
       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         top

       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         top

       curses(3X), menu(3X), getch(3X).

NOTES         top

       The header file <menu.h> automatically includes the header files
       <curses.h>.

PORTABILITY         top

       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         top

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

COLOPHON         top

       This page is part of the ncurses (new curses) project.  Information
       about the project can be found at 
       ⟨https://www.gnu.org/software/ncurses/ncurses.html⟩.  If you have a
       bug report for this manual page, send it to
       bug-ncurses-request@gnu.org.  This page was obtained from the
       project's upstream Git mirror of the CVS repository 
       ⟨git://ncurses.scripts.mit.edu/ncurses.git⟩ on 2017-07-05.  If you
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       or you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

                                                             menu_driver(3X)