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
       two  major input cases; either the input is a menu naviga-
       tion request or it's a  printable  ASCII  character.   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.

            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 neither printable ASCII nor  one
       of  the above pre-defined menu requests, 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.
            The menu driver could not process the request.

SEE ALSO

       curses(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 supported on Version 7 or BSD versions.

AUTHORS

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