+typedef enum _node_verification_t {
+ NODE_VERIFICATION_OFF = 0, /**< do not verify nodes at all */
+ NODE_VERIFICATION_ON = 1, /**< do node verification and assert on error in debug version */
+ NODE_VERIFICATION_REPORT = 2, /**< do node verification, but report to stderr only */
+ NODE_VERIFICATION_ERROR_ONLY = 3 /**< do node verification, but NEVER do assert nor report */
+} node_verification_t;
+
+/** Select verification of nodes.
+ *
+ * Per default the verification is in mode NODE_VERIFICATION_ASSERT.
+ * Turn the verification off during development to check partial implementations.
+ */
+void do_node_verification(node_verification_t mode);
+