-bool interface_name_is_valid(const char *p);
-bool service_name_is_valid(const char *p);
-bool member_name_is_valid(const char *p);
-bool object_path_is_valid(const char *p);
-char *object_path_startswith(const char *a, const char *b);
+bool interface_name_is_valid(const char *p) _pure_;
+bool service_name_is_valid(const char *p) _pure_;
+bool member_name_is_valid(const char *p) _pure_;
+bool object_path_is_valid(const char *p) _pure_;
+char *object_path_startswith(const char *a, const char *b) _pure_;