--- speech_tools/include/EST_Chunk.h
+++ speech_tools/include/EST_Chunk.h
@@ -142,15 +142,15 @@
   public:
     friend class EST_ChunkPtr;
 
-    friend EST_ChunkPtr chunk_allocate(int bytes);
-    friend EST_ChunkPtr chunk_allocate(int bytes, const char *initial, int initial_len);
-    friend EST_ChunkPtr chunk_allocate(int bytes, const EST_ChunkPtr &initial, int initial_start, int initial_len);
+    friend class EST_ChunkPtr chunk_allocate(int bytes);
+    friend class EST_ChunkPtr chunk_allocate(int bytes, const char *initial, int initial_len);
+    friend class EST_ChunkPtr chunk_allocate(int bytes, const class EST_ChunkPtr &initial, int initial_start, int initial_len);
 
-    friend void cp_make_updatable(EST_ChunkPtr &shared, EST_chunk_size inuse);
-    friend void cp_make_updatable(EST_ChunkPtr &shared);
+    friend void cp_make_updatable(class EST_ChunkPtr &shared, EST_chunk_size inuse);
+    friend void cp_make_updatable(class EST_ChunkPtr &shared);
 
-    friend void grow_chunk(EST_ChunkPtr &shared, EST_chunk_size inuse, EST_chunk_size newsize);
-    friend void grow_chunk(EST_ChunkPtr &shared, EST_chunk_size newsize);
+    friend void grow_chunk(class EST_ChunkPtr &shared, EST_chunk_size inuse, EST_chunk_size newsize);
+    friend void grow_chunk(class EST_ChunkPtr &shared, EST_chunk_size newsize);
 
     friend ostream &operator << (ostream &s, const EST_Chunk &chp);
     friend void tester(void);