*/
#define VALUE_NONE 0xdeadbeef
+/**
+ * @brief The "location" at which a fence occurs
+ *
+ * We need a non-zero memory location to associate with fences, since our hash
+ * tables don't handle NULL-pointer keys. HACK: Hopefully this doesn't collide
+ * with any legitimate memory locations.
+ */
+#define FENCE_LOCATION ((void *)0x7)
+
/** @brief Represents an action type, identifying one of several types of
* ModelAction */
typedef enum action_type {