-bool cgroup_attribute_matches(CGroupAttribute *a, const char *controller, const char *name);
-CGroupAttribute *cgroup_attribute_find_list(CGroupAttribute *first, const char *controller, const char *name);
+bool cgroup_attribute_matches(CGroupAttribute *a, const char *controller, const char *name) _pure_;
+CGroupAttribute *cgroup_attribute_find_list(CGroupAttribute *first, const char *controller, const char *name) _pure_;