-XBT_PUBLIC void simgrid_register_function(const char* name, int (*code)(int, char**));
-XBT_PUBLIC void simgrid_register_default(int (*code)(int, char**));
+/** Registers the main function of an actor that will be launched from the deployment file */
+XBT_PUBLIC void simgrid_register_function(const char* name, void (*code)(int, char**));
+/** Registers a function as the default main function of actors
+ *
+ * It will be used as fallback when the function requested from the deployment file was not registered.
+ * It is used for trace-based simulations (see examples/s4u/replay-comms and similar).
+ */
+XBT_PUBLIC void simgrid_register_default(void (*code)(int, char**));
+/** Retrieve the simulation time (in seconds) */