+XBT_PUBLIC(void) SD_task_set_category (SD_task_t task, const char *category);
+XBT_PUBLIC(const char *) SD_task_get_category (SD_task_t task);
+
+
+/** @brief A constant to use in SD_task_schedule to mean that there is no cost.
+ *
+ * For example, create a pure computation task (no comm) like this:
+ *
+ * SD_task_schedule(task, my_workstation_nb,
+ * my_workstation_list,
+ * my_computation_amount,
+ * SD_TASK_SCHED_NO_COST,
+ * my_rate);
+ */
+#define SD_SCHED_NO_COST NULL