diff --git a/pvDataApp/misc/bitSet.h b/pvDataApp/misc/bitSet.h
index 0d21828..c291a19 100644
--- a/pvDataApp/misc/bitSet.h
+++ b/pvDataApp/misc/bitSet.h
@@ -13,6 +13,9 @@
 
 namespace epics { namespace pvData { 
 
+    class BitSet;
+    typedef std::tr1::shared_ptr<BitSet> BitSetPtr;
+
     /**
      * This class implements a vector of bits that grows as needed. Each
      * component of the bit set has a {@code bool} value. The
diff --git a/pvDataApp/monitor/monitor.h b/pvDataApp/monitor/monitor.h
index 14b6b20..fe76ad5 100644
--- a/pvDataApp/monitor/monitor.h
+++ b/pvDataApp/monitor/monitor.h
@@ -31,7 +31,7 @@ class MonitorElement {
     public:
     POINTER_DEFINITIONS(MonitorElement);
     MonitorElement(){}
-    MonitorElement(PVStructurePtr &pvStructurePtr)
+    MonitorElement(PVStructurePtr const &pvStructurePtr)
     : pvStructurePtr(pvStructurePtr),
       changedBitSet(BitSet::create(pvStructurePtr->getNumberFields())),
       overrunBitSet(BitSet::create(pvStructurePtr->getNumberFields()))
@@ -64,12 +64,12 @@ class Monitor : public Destroyable{
      * @return monitorElement for modified data.
      * Must call get to determine if data is available.
      */
-    virtual MonitorElementPtr poll() = 0;
+    virtual MonitorElementPtr &poll() = 0;
     /**
      * Release a MonitorElement that was returned by poll.
      * @param monitorElement
      */
-    virtual void release(MonitorElementPtr & monitorElement) = 0;
+    virtual void release(MonitorElementPtr const & monitorElement) = 0;
 };
 
 
@@ -88,7 +88,7 @@ class MonitorRequester : public virtual Requester {
      * @param structure The structure defining the data.
      */
     virtual void monitorConnect(Status const &status,
-        MonitorPtr & monitor, StructureConstPtr const & structure) = 0;
+        MonitorPtr const & monitor, StructureConstPtr const & structure) = 0;
     /**
      * A monitor event has occurred.
      * The requester must call Monitor.poll to get data.
diff --git a/testApp/monitor/testMonitor.cpp b/testApp/monitor/testMonitor.cpp
index 5bc81ed..f42037c 100644
--- a/testApp/monitor/testMonitor.cpp
+++ b/testApp/monitor/testMonitor.cpp
@@ -45,12 +45,12 @@ public:
         printf("stop called\n");
         return status;
     }
-    virtual MonitorElementPtr poll()
+    virtual MonitorElementPtr &poll()
     {
         printf("poll called\n");
         return emptyElement;
     }
-    virtual void release(MonitorElementPtr & monitorElement)
+    virtual void release(MonitorElementPtr const & monitorElement)
     {
         printf("release called\n");
     }