menu_driver - command-processing loop of the menu system
#include <menu.h> int menu_driver(MENU *menu, int c);
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(3x). 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.
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.
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.
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.
curses(3x), menu(3x), getch(3x).
The header file <menu.h> automatically includes the header files <curses.h>.
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.
Juergen Pfeifer. Manual pages and adaptation for new curses by Eric S. Raymond. menu_driver(3x)