diff --git a/include/villas/hist.h b/include/villas/hist.h
index fefd3a728..289affa78 100644
--- a/include/villas/hist.h
+++ b/include/villas/hist.h
@@ -44,7 +44,7 @@ struct hist {
 void hist_create(struct hist *h, double start, double end, double resolution);
 
 /** Free the dynamically allocated memory. */
-void hist_destroy(struct hist *h);
+int hist_destroy(struct hist *h);
 
 /** Reset all counters and values back to zero. */
 void hist_reset(struct hist *h);
diff --git a/include/villas/list.h b/include/villas/list.h
index 2e3e5ec6c..26d10fbaf 100644
--- a/include/villas/list.h
+++ b/include/villas/list.h
@@ -40,7 +40,7 @@
  *
  * @param data A pointer to the data which should be freed.
  */
-typedef void (*dtor_cb_t)(void *);
+typedef int (*dtor_cb_t)(void *);
 
 /** Callback to search or sort a list. */	
 typedef int (*cmp_cb_t)(const void *, const void *);
@@ -65,7 +65,7 @@ void list_init(struct list *l);
  * @param dtor A function pointer to a desctructor which will be called for every list item when the list is destroyed.
  * @param l A pointer to the list data structure.
  */
-void list_destroy(struct list *l, dtor_cb_t dtor, bool free);
+int list_destroy(struct list *l, dtor_cb_t dtor, bool free);
 
 /** Append an element to the end of the list */
 void list_push(struct list *l, void *p);
diff --git a/include/villas/node.h b/include/villas/node.h
index af24a35cb..19111cec4 100644
--- a/include/villas/node.h
+++ b/include/villas/node.h
@@ -198,7 +198,7 @@ struct node * node_create(struct node_type *vt);
  *
  * @see node_type::destroy
  */
-void node_destroy(struct node *n);
+int node_destroy(struct node *n);
 
 /** Start operation of a node.
  *
diff --git a/include/villas/path.h b/include/villas/path.h
index e09109a3e..6aec9ed5c 100644
--- a/include/villas/path.h
+++ b/include/villas/path.h
@@ -85,7 +85,7 @@ void path_init(struct path *p);
  *
  * @param i A pointer to the path structure.
  */
-void path_destroy(struct path *p);
+int path_destroy(struct path *p);
 
 /** Initialize  pool queue and hooks.
  *
diff --git a/lib/hist.c b/lib/hist.c
index 8f29f6597..89da433e5 100644
--- a/lib/hist.c
+++ b/lib/hist.c
@@ -30,9 +30,11 @@ void hist_create(struct hist *h, double low, double high, double resolution)
 	hist_reset(h);
 }
 
-void hist_destroy(struct hist *h)
+int hist_destroy(struct hist *h)
 {
 	free(h->data);
+	
+	return 0;
 }
 
 void hist_put(struct hist *h, double value)
diff --git a/lib/list.c b/lib/list.c
index aa87553de..77f6f3fd5 100644
--- a/lib/list.c
+++ b/lib/list.c
@@ -42,7 +42,7 @@ void list_init(struct list *l)
 	l->array = NULL;
 }
 
-void list_destroy(struct list *l, dtor_cb_t destructor, bool release)
+int list_destroy(struct list *l, dtor_cb_t destructor, bool release)
 {
 	pthread_mutex_lock(&l->lock);
 
@@ -62,6 +62,8 @@ void list_destroy(struct list *l, dtor_cb_t destructor, bool release)
 
 	pthread_mutex_unlock(&l->lock);
 	pthread_mutex_destroy(&l->lock);
+	
+	return 0;
 }
 
 void list_push(struct list *l, void *p)
diff --git a/lib/node.c b/lib/node.c
index b4aa9dc02..9a4284e04 100644
--- a/lib/node.c
+++ b/lib/node.c
@@ -193,7 +193,7 @@ struct node * node_create(struct node_type *vt)
 	return n;
 }
 
-void node_destroy(struct node *n)
+int node_destroy(struct node *n)
 {
 	if (n->_vt->destroy)
 		n->_vt->destroy(n);
@@ -203,4 +203,6 @@ void node_destroy(struct node *n)
 	free(n->_vd);
 	free(n->_name);
 	free(n);
+	
+	return 0;
 }
diff --git a/lib/nodes/ngsi.c b/lib/nodes/ngsi.c
index e50b1c25c..d675eb056 100644
--- a/lib/nodes/ngsi.c
+++ b/lib/nodes/ngsi.c
@@ -429,26 +429,30 @@ char * ngsi_print(struct node *n)
 		i->endpoint, i->timeout, list_length(&i->mapping));
 }
 
-static void ngsi_destroy_metadata(struct ngsi_metadata *meta)
+static int ngsi_metadata_destroy(struct ngsi_metadata *meta)
 {
 	free(meta->value);
 	free(meta->name);
 	free(meta->type);
+	
+	return 0;
 }
 
-static void ngsi_destroy_attribute(struct ngsi_attribute *attr)
+static int ngsi_attribute_destroy(struct ngsi_attribute *attr)
 {
 	free(attr->name);
 	free(attr->type);
 	
-	list_destroy(&attr->metadata, (dtor_cb_t) ngsi_destroy_metadata, true);
+	list_destroy(&attr->metadata, (dtor_cb_t) ngsi_metadata_destroy, true);
+	
+	return 0;
 }
 
 int ngsi_destroy(struct node *n)
 {
 	struct ngsi *i = n->_vd;
 	
-	list_destroy(&i->mapping, (dtor_cb_t) ngsi_destroy_attribute, true);
+	list_destroy(&i->mapping, (dtor_cb_t) ngsi_attribute_destroy, true);
 	
 	return 0;
 }
diff --git a/lib/path.c b/lib/path.c
index a1693f2b1..d860ceac1 100644
--- a/lib/path.c
+++ b/lib/path.c
@@ -197,6 +197,21 @@ void path_init(struct path *p)
 	p->state = PATH_CREATED;
 }
 
+int path_destroy(struct path *p)
+{
+	hook_run(p, NULL, 0, HOOK_DEINIT); /* Release memory */
+	
+	list_destroy(&p->destinations, NULL, false);
+	list_destroy(&p->hooks, NULL, true);
+	
+	queue_destroy(&p->queue);
+	pool_destroy(&p->pool);
+
+	free(p->_name);
+	
+	return 0;
+}
+
 int path_prepare(struct path *p)
 {
 	int ret;
@@ -226,19 +241,6 @@ int path_prepare(struct path *p)
 	return 0;
 }
 
-void path_destroy(struct path *p)
-{
-	hook_run(p, NULL, 0, HOOK_DEINIT); /* Release memory */
-	
-	list_destroy(&p->destinations, NULL, false);
-	list_destroy(&p->hooks, NULL, true);
-	
-	queue_destroy(&p->queue);
-	pool_destroy(&p->pool);
-
-	free(p->_name);
-}
-
 int path_uses_node(struct path *p, struct node *n) {
 	return (p->in == n) || list_contains(&p->destinations, n) ? 0 : 1;
 }
diff --git a/lib/pool.c b/lib/pool.c
index d84f24c81..9d3c7f0b6 100644
--- a/lib/pool.c
+++ b/lib/pool.c
@@ -43,4 +43,6 @@ int pool_destroy(struct pool *p)
 	queue_destroy(&p->queue);	
 
 	return memory_free(p->mem, p->buffer, p->len);
+	
+	return 0;
 }
\ No newline at end of file