bool my_function(JSContext* cx, unsigned argc, JS::Value* vp) { // Use CallArgs to get the arguments passed to this function by JavaScript JS::CallArgs args = JS::CallArgsFromVp(argc, vp); // Check the number of arguments is correct if (args.length() != 2) { JS_ReportError(cx, "Wrong number of arguments"); return false; } // Get the first argument (which should be a string) and convert it to a C++ std::string JS::RootedString str(cx, args.get(0).toString()); JSStringWrapper str_wrapper(str); std::string str_value = str_wrapper.get(); // Get the second argument (which should be a number) double num_value = args.get(1).toNumber(); // Do something with the arguments... // ... // Set the return value back to JavaScript args.rval().setNumber(42); return true; }In this example, the C++ function receives two arguments from JavaScript and returns the number 42. The "JS::CallArgs" object is used to get the arguments and set the return value. Overall, the "CallArgs" class is used for passing arguments between JavaScript and C++ code in the SpiderMonkey engine.