diff --git a/pvDataApp/factory/PVStructure.cpp b/pvDataApp/factory/PVStructure.cpp
index 7090997..62b2af5 100644
--- a/pvDataApp/factory/PVStructure.cpp
+++ b/pvDataApp/factory/PVStructure.cpp
@@ -52,14 +52,14 @@ PVStructure::PVStructure(StructureConstPtr const & structurePtr)
     size_t numberFields = structurePtr->getNumberFields();
     FieldConstPtrArray fields = structurePtr->getFields();
     StringArray fieldNames = structurePtr->getFieldNames();
-    PVFieldPtrArray * xxx = const_cast<PVFieldPtrArray *>(&pvFields);
-    xxx->reserve(numberFields);
+//    PVFieldPtrArray * xxx = const_cast<PVFieldPtrArray *>(&pvFields);
+    pvFields.reserve(numberFields);
     PVDataCreatePtr pvDataCreate = getPVDataCreate();
     for(size_t i=0; i<numberFields; i++) {
-        xxx->push_back(pvDataCreate->createPVField(fields[i]));
+    	pvFields.push_back(pvDataCreate->createPVField(fields[i]));
     }
     for(size_t i=0; i<numberFields; i++) {
-        (*xxx)[i]->setParentAndName(this,fieldNames[i]);
+    	pvFields[i]->setParentAndName(this,fieldNames[i]);
     }
 }
 
@@ -560,21 +560,24 @@ bool PVStructure::putExtendsStructureName(
 
 void PVStructure::serialize(ByteBuffer *pbuffer,
         SerializableControl *pflusher) const {
-    for(size_t i = 0; i<pvFields.size(); i++)
+    size_t fieldsSize = pvFields.size();
+    for(size_t i = 0; i<fieldsSize; i++)
         pvFields[i]->serialize(pbuffer, pflusher);
 }
 
 void PVStructure::deserialize(ByteBuffer *pbuffer,
         DeserializableControl *pcontrol) {
-    for(size_t i = 0; i<pvFields.size(); i++)
+    size_t fieldsSize = pvFields.size();
+    for(size_t i = 0; i<fieldsSize; i++)
         pvFields[i]->deserialize(pbuffer, pcontrol);
 
 }
 
 void PVStructure::serialize(ByteBuffer *pbuffer,
         SerializableControl *pflusher, BitSet *pbitSet) const {
-    size_t numberFields = const_cast<PVStructure*>(this)->getNumberFields();
-    size_t offset = const_cast<PVStructure*>(this)->getFieldOffset();
+	PVStructure* nonConstThis = const_cast<PVStructure*>(this);
+    size_t numberFields = nonConstThis->getNumberFields();
+    size_t offset = nonConstThis->getFieldOffset();
     int32 next = pbitSet->nextSetBit(offset);
 
     // no more changes or no changes in this structure
@@ -586,8 +589,9 @@ void PVStructure::serialize(ByteBuffer *pbuffer,
         return;
     }
 
-    for(size_t i = 0; i<numberFields; i++) {
-        PVFieldPtr pvField  = pvFields[i];
+    size_t fieldsSize = pvFields.size();
+    for(size_t i = 0; i<fieldsSize; i++) {
+        PVFieldPtr pvField = pvFields[i];
         offset = pvField->getFieldOffset();
         int32 inumberFields = pvField->getNumberFields();
         next = pbitSet->nextSetBit(offset);
@@ -611,29 +615,30 @@ void PVStructure::deserialize(ByteBuffer *pbuffer,
         DeserializableControl *pcontrol, BitSet *pbitSet) {
     size_t offset = getFieldOffset();
     size_t numberFields = getNumberFields();
-    size_t next = pbitSet->nextSetBit(offset);
+    int32 next = pbitSet->nextSetBit(offset);
 
     // no more changes or no changes in this structure
-    if(next<0||next>=offset+numberFields) return;
+    if(next<0||next>=static_cast<int32>(offset+numberFields)) return;
 
     // entire structure
-    if(offset==next) {
+    if(static_cast<int32>(offset)==next) {
         deserialize(pbuffer, pcontrol);
         return;
     }
 
-    for(size_t i = 0; i<numberFields; i++) {
-        PVFieldPtr pvField  = pvFields[i];
+    size_t fieldsSize = pvFields.size();
+    for(size_t i = 0; i<fieldsSize; i++) {
+        PVFieldPtr pvField = pvFields[i];
         offset = pvField->getFieldOffset();
-        numberFields = pvField->getNumberFields();
+        int32 inumberFields = pvField->getNumberFields();
         next = pbitSet->nextSetBit(offset);
         // no more changes
         if(next<0) return;
         //  no change in this pvField
-        if(next>=offset+numberFields) continue;
+        if(next>=static_cast<int32>(offset+inumberFields)) continue;
 
         // deserialize field or fields
-        if(numberFields==1) {
+        if(inumberFields==1) {
             pvField->deserialize(pbuffer, pcontrol);
         } else {
             PVStructurePtr pvStructure = std::tr1::static_pointer_cast<PVStructure>(pvField);
diff --git a/pvDataApp/pv/pvData.h b/pvDataApp/pv/pvData.h
index 507f2df..d30617b 100644
--- a/pvDataApp/pv/pvData.h
+++ b/pvDataApp/pv/pvData.h
@@ -814,7 +814,7 @@ public:
      */
     PVStructure(StructureConstPtr const & structure,PVFieldPtrArray const & pvFields);
 private:
-    const PVFieldPtrArray pvFields;
+    PVFieldPtrArray pvFields;
     StructureConstPtr structurePtr;
     String extendsStructureName;
     friend class PVDataCreate;