-extern int _sg_do_model_check; /* please don't use directly: we inline MC_is_active, but that's what you should use */
-extern int _sg_mc_visited;
+/* Internal variable used to check if we're running under the MC. Please use MC_is_active instead. */
+extern XBT_PUBLIC int _sg_do_model_check;
+extern XBT_PUBLIC int _sg_mc_max_visited_states;
+
+#define MC_is_active() _sg_do_model_check
+#define MC_visited_reduction() _sg_mc_max_visited_states
+
+/** Assertion for the model-checker
+ *
+ * This function is used to define safety properties to verify.
+ */
+XBT_PUBLIC void MC_assert(int);