diff --git a/C/init.c b/C/init.c
index 031f15ba5..b21920970 100644
--- a/C/init.c
+++ b/C/init.c
@@ -1346,9 +1346,6 @@ InitVersion(void)
 }
 
 
-#define K		((Int) 1024)
-
-
 void
 Yap_InitWorkspace(int Heap, int Stack, int Trail, int max_table_size, 
                   int n_workers, int sch_loop, int delay_load)
diff --git a/C/threads.c b/C/threads.c
index a995c5206..dab43607e 100644
--- a/C/threads.c
+++ b/C/threads.c
@@ -384,10 +384,16 @@ p_thread_destroy(void)
 static Int
 p_thread_detach(void)
 {
-  if (pthread_detach(ThreadHandle[IntegerOfTerm(Deref(ARG1))].handle) < 0) {
+  Int tid = IntegerOfTerm(Deref(ARG1));
+  pthread_mutex_lock(&(ThreadHandle[tid].tlock));
+  if (pthread_detach(ThreadHandle[tid].handle) < 0) {
     /* ERROR */
+    pthread_mutex_unlock(&(ThreadHandle[tid].tlock));
     return FALSE;
   }
+  ThreadHandle[tid].tdetach = 
+    MkAtomTerm(AtomTrue);
+  pthread_mutex_unlock(&(ThreadHandle[tid].tlock));
   return TRUE;
 }
 
diff --git a/H/alloc.h b/H/alloc.h
index 61de0878c..97d063a65 100644
--- a/H/alloc.h
+++ b/H/alloc.h
@@ -55,6 +55,8 @@ typedef	struct FREEB {
   struct FREEB		*b_next_size;
 } BlockHeader;
 
+#define K		((Int) 1024)
+
 #define MinBlockSize	(sizeof(BlockHeader)+sizeof(YAP_SEG_SIZE))
 #define MaxBlockSize	0xffffff
 #define	InUseFlag	0x80000000
@@ -138,4 +140,3 @@ void Yap_add_memory_hole(ADDR, ADDR);
 #define SCRATCH_START_SIZE        (64*1024L)
 #define SCRATCH_INC_SIZE          (64*1024L)
 
-
diff --git a/library/dgraphs.yap b/library/dgraphs.yap
index 282b37b7e..008911c21 100644
--- a/library/dgraphs.yap
+++ b/library/dgraphs.yap
@@ -31,8 +31,7 @@
 	    dgraph_max_path/5,
 	    dgraph_min_paths/3,
 	    dgraph_isomorphic/4,
-	    dgraph_path/3,
-	    dgraph_connected_components]).
+	    dgraph_path/3]).
 
 :- reexport(library(rbtrees),
 	[rb_new/1 as dgraph_new]).
diff --git a/library/undgraphs.yap b/library/undgraphs.yap
index e13313bf6..4ab65576d 100644
--- a/library/undgraphs.yap
+++ b/library/undgraphs.yap
@@ -18,6 +18,7 @@
 	    undgraph_neighbors/3,
 	    undgraph_neighbours/3,
 	    undgraph_complement/2,
+	    undgraph_components/2,
 	    dgraph_to_undgraph/2,
 	    undgraph_min_tree/2]).
 
@@ -58,6 +59,8 @@
 
 :- use_module(library(rbtrees),
 	[  rb_delete/4,
+	   rb_insert/4,
+	   rb_in/3,
 	   rb_partial_map/4
 	]).
 
@@ -160,4 +163,24 @@ undgraph_max_tree(G, T) :-
 	wundgraph_max_tree(WG, WT, _),
 	wundgraph_to_undgraph(WT, T).
 
-
+undgraph_components(Graph,[Map|Gs]) :-
+	pick_node(Graph,Node,Children,Graph1), !,
+	undgraph_new(Map0),
+	rb_insert(Map0, Node, Children, Map1),
+	expand_component(Children, Map1, Map, Graph1, NGraph),
+	undgraph_components(NGraph,Gs).
+undgraph_components(_,[]).
+	
+expand_component([], Map, Map, Graph, Graph).
+expand_component([C|Children], Map1, Map, Graph1, NGraph) :-
+	rb_delete(Graph1, C, Edges, Graph2), !,
+	rb_insert(Map1, C, Edges, Map2),
+	expand_component(Children, Map2, Map3, Graph2, Graph3),
+	expand_component(Edges, Map3, Map, Graph3, NGraph).
+expand_component([C|Children], Map1, Map, Graph1, NGraph) :-
+	expand_component(Children, Map1, Map, Graph3, NGraph).
+	
+	
+pick_node(Graph,Node,Children,Graph1) :-
+	rb_in(Node,Children,Graph), !,
+	rb_delete(Graph, Node, Graph1).