The handler routine is required by the windowing system and must be declared in the following way. It will be passed in two objects - a Menu_item and a Menu_generate. These are special XView window objects and the user should refer to The XView Programming Manual [2] for more information. The important fact for this routine is that when the Menu_generate item has value equal to MENU_NOTIFY then the user has selected this option from the menu so the computational procedure should be called. The menu object types are declared in the file <xview/xview.h> which must be included into this C code file. The handler routine should also return the Menu_item object when it exits. The following code is a sample handler routine.
#include <xview/xview.h> /* include the xview declarations for */ /* Menu_item, Menu_generate, and MENU_NOTIFY */ /* * example_handler() * * Menu handler for `panelmenu (Example)'. */ Menu_item example_handler(item, op) Menu_item item; Menu_generate op; { if (op == MENU_NOTIFY) { example_go(); } return item; }