+/** Fulfill a promise by executing a given code */
+template<class R, class F>
+void fulfill_promise(std::promise<R>& promise, F&& code)
+{
+ try {
+ promise.set_value(std::forward<F>(code)());
+ }
+ catch(...) {
+ promise.set_exception(std::current_exception());
+ }
+}
+
+/** Fulfill a promise by executing a given code
+ *
+ * This is a special version for `std::promise<void>` because the default
+ * version does not compile in this case.
+ */
+template<class F>
+void fulfill_promise(std::promise<void>& promise, F&& code)
+{
+ try {
+ std::forward<F>(code)();
+ promise.set_value();
+ }
+ catch(...) {
+ promise.set_exception(std::current_exception());
+ }
+}
+
+/** Execute some code in the kernel/maestro
+ *
+ * This can be used to enforce mutual exclusion with other simcall.
+ * More importantly, this enforces a deterministic/reproducible ordering
+ * of the operation with respect to other simcalls.
+ */
+template<class F>
+typename std::result_of<F()>::type kernel(F&& code)
+{
+ // If we are in the maestro, we take the fast path and execute the
+ // code directly without simcall mashalling/unmarshalling/dispatch:
+ if (SIMIX_is_maestro())
+ return std::forward<F>(code)();
+
+ // If we are in the application, pass the code to the maestro which is
+ // executes it for us and reports the result. We use a std::future which
+ // conveniently handles the success/failure value for us.
+ typedef typename std::result_of<F()>::type R;
+ std::promise<R> promise;
+ simcall_run_kernel([&]{
+ xbt_assert(SIMIX_is_maestro(), "Not in maestro");
+ fulfill_promise(promise, std::forward<F>(code));
+ });
+ return promise.get_future().get();
+}
+