+ /** @brief Set application information associated with the #MDB_env.
+ *
+ * @param[in] env An environment handle returned by #mdb_env_create()
+ * @param[in] ctx An arbitrary pointer for whatever the application needs.
+ * @return A non-zero error value on failure and 0 on success.
+ */
+int mdb_env_set_userctx(MDB_env *env, void *ctx);
+
+ /** @brief Get the application information associated with the #MDB_env.
+ *
+ * @param[in] env An environment handle returned by #mdb_env_create()
+ * @return The pointer set by #mdb_env_set_userctx().
+ */
+void *mdb_env_get_userctx(MDB_env *env);
+
+ /** @brief A callback function for most MDB assert() failures,
+ * called before printing the message and aborting.
+ *
+ * @param[in] env An environment handle returned by #mdb_env_create().
+ * @param[in] msg The assertion message, not including newline.
+ */
+typedef void MDB_assert_func(MDB_env *env, const char *msg);
+
+ /** Set or reset the assert() callback of the environment.
+ * Disabled if liblmdb is buillt with NDEBUG.
+ * @note This hack should become obsolete as lmdb's error handling matures.
+ * @param[in] env An environment handle returned by #mdb_env_create().
+ * @parem[in] func An #MDB_assert_func function, or 0.
+ * @return A non-zero error value on failure and 0 on success.
+ */
+int mdb_env_set_assert(MDB_env *env, MDB_assert_func *func);
+