-namespace simix {
-
-template<class R, class F>
-void fulfill_promise(std::promise<R>& promise, F&& code)
+namespace kernel {
+namespace actor {
+
+/** Execute some code in kernel context on behalf of the user code.
+ *
+ * Every modification of the environment must be protected this way: every setter, constructor and similar.
+ * Getters don't have to be protected this way.
+ *
+ * This allows deterministic parallel simulation without any locking, even if almost nobody uses parallel simulation in
+ * SimGrid. More interestingly it makes every modification of the simulated world observable by the model-checker,
+ * allowing the whole MC business.
+ *
+ * It is highly inspired from the syscalls in a regular operating system, allowing the user code to get some specific
+ * code executed in the kernel context. But here, there is almost no security involved. Parameters get checked for
+ * finitness but that's all. The main goal remain to ensure reproductible ordering of uncomparable events (in [parallel]
+ * simulation) and observability of events (in model-checking).
+ *
+ * The code passed as argument is supposed to terminate at the exact same simulated timestamp.
+ * Do not use it if your code may block waiting for a subsequent event, e.g. if you lock a mutex,
+ * you may need to wait for that mutex to be unlocked by its current owner.
+ * Potentially blocking simcall must be issued using simcall_blocking(), right below in this file.
+ */
+template <class F> typename std::result_of<F()>::type simcall(F&& code, mc::SimcallInspector* t = nullptr)