diff --git a/src/nt/ntfield.cpp b/src/nt/ntfield.cpp
index ecb4575..526d694 100644
--- a/src/nt/ntfield.cpp
+++ b/src/nt/ntfield.cpp
@@ -8,16 +8,18 @@
 #include <pv/lock.h>
 #include <pv/ntfield.h>
 
+using std::tr1::static_pointer_cast;
+
 namespace epics { namespace pvData { 
 
-
-
-NTField *NTField::get()
+NTFieldPtr NTField::get()
 {
     static Mutex mutex;
-    static NTField *ntstructureField = 0;
+    static NTFieldPtr ntstructureField;
     Lock xx(mutex);
-    if(ntstructureField==0) ntstructureField = new NTField();
+    if(ntstructureField.get()==NULL) {
+         ntstructureField = NTFieldPtr(new NTField());
+    }
     return ntstructureField;
 }
 
@@ -27,189 +29,195 @@ NTField::NTField()
 {
 }
 
-bool NTField::isEnumerated(FieldConstPtr field)
+bool NTField::isEnumerated(FieldConstPtr const & field)
 {
    if(field->getType()!=structure) return false;
-   const Structure *st = static_cast<const Structure *>(field.get());
-   FieldConstPtrArray fields = st->getFields();
-   int n = st->getNumberFields();
+   StructureConstPtr structurePtr = static_pointer_cast<const Structure>(field);
+   FieldConstPtrArray fields = structurePtr->getFields();
+   StringArray names = structurePtr->getFieldNames();
+   size_t n = structurePtr->getNumberFields();
    if(n!=2) return false;
    FieldConstPtr f = fields[0];
-   if(f->getFieldName().compare("index")!=0) return false;
+   if(names[0].compare("index")!=0) return false;
    if(f->getType()!=scalar) return false;
-   const Scalar* s = static_cast<const Scalar*>(f.get());
+   ScalarConstPtr s = static_pointer_cast<const Scalar>(f);
    if(s->getScalarType()!=pvInt) return false;
    f = fields[1];
-   if(f->getFieldName().compare("choices")!=0) return false;
+   if(names[1].compare("choices")!=0) return false;
    if(f->getType()!=scalarArray) return false;
-   const ScalarArray* sa = static_cast<const ScalarArray*>(f.get());
-   if(sa->getElementType()!=pvString) return false;
+   ScalarConstPtr sa = static_pointer_cast<const Scalar>(f);
+   if(sa->getScalarType()!=pvString) return false;
    return true;
 }
 
-bool NTField::isTimeStamp(FieldConstPtr field)
+bool NTField::isTimeStamp(FieldConstPtr const & field)
 {
    if(field->getType()!=structure) return false;
-   const Structure *st = static_cast<const Structure *>(field.get());
-   if(field->getFieldName().compare("timeStamp")!=0) return false;
-   FieldConstPtrArray fields = st->getFields();
-   int n = st->getNumberFields();
+   StructureConstPtr structurePtr = static_pointer_cast<const Structure>(field);
+   FieldConstPtrArray fields = structurePtr->getFields();
+   StringArray names = structurePtr->getFieldNames();
+   size_t  n = structurePtr->getNumberFields();
    if(n!=3) return false;
    FieldConstPtr f = fields[0];
-   if(f->getFieldName().compare("secondsPastEpoch")!=0) return false;
+   if(names[0].compare("secondsPastEpoch")!=0) return false;
    if(f->getType()!=scalar) return false;
-   const Scalar* s = static_cast<const Scalar*>(f.get());
+   ScalarConstPtr s = static_pointer_cast<const Scalar>(f);
    if(s->getScalarType()!=pvLong) return false;
    f = fields[1];
-   if(f->getFieldName().compare("nanoSeconds")!=0) return false;
+   if(names[1].compare("nanoSeconds")!=0) return false;
    if(f->getType()!=scalar) return false;
-   s = static_cast<const Scalar*>(f.get());
+   s = static_pointer_cast<const Scalar>(f);
    if(s->getScalarType()!=pvInt) return false;
    f = fields[2];
-   if(f->getFieldName().compare("userTag")!=0) return false;
+   if(names[2].compare("userTag")!=0) return false;
    if(f->getType()!=scalar) return false;
-   s = static_cast<const Scalar*>(f.get());
+   s = static_pointer_cast<const Scalar>(f);
    if(s->getScalarType()!=pvInt) return false;
    return true;
 }
 
-bool NTField::isAlarm(FieldConstPtr field)
+bool NTField::isAlarm(FieldConstPtr const & field)
 {
    if(field->getType()!=structure) return false;
-   const Structure *st = static_cast<const Structure *>(field.get());
-   if(field->getFieldName().compare("alarm")!=0) return false;
-   FieldConstPtrArray fields = st->getFields();
-   int n = st->getNumberFields();
+   StructureConstPtr structurePtr = static_pointer_cast<const Structure>(field);
+   FieldConstPtrArray fields = structurePtr->getFields();
+   StringArray names = structurePtr->getFieldNames();
+   size_t n = structurePtr->getNumberFields();
    if(n!=3) return false;
    FieldConstPtr f = fields[0];
-   if(f->getFieldName().compare("severity")!=0) return false;
+   if(names[0].compare("severity")!=0) return false;
    if(f->getType()!=scalar) return false;
-   const Scalar* s = static_cast<const Scalar*>(f.get());
+   ScalarConstPtr s = static_pointer_cast<const Scalar>(f);
    if(s->getScalarType()!=pvInt) return false;
    f = fields[1];
-   if(f->getFieldName().compare("status")!=0) return false;
+   if(names[1].compare("status")!=0) return false;
    if(f->getType()!=scalar) return false;
-   s = static_cast<const Scalar*>(f.get());
+   s = static_pointer_cast<const Scalar>(f);
    if(s->getScalarType()!=pvInt) return false;
    f = fields[2];
-   if(f->getFieldName().compare("message")!=0) return false;
+   if(names[2].compare("message")!=0) return false;
    if(f->getType()!=scalar) return false;
-   s = static_cast<const Scalar*>(f.get());
+   s = static_pointer_cast<const Scalar>(f);
    if(s->getScalarType()!=pvString) return false;
    return true;
 }
 
-bool NTField::isDisplay(FieldConstPtr field)
+bool NTField::isDisplay(FieldConstPtr const & field)
 {
    if(field->getType()!=structure) return false;
-   const Structure *st = static_cast<const Structure *>(field.get());
-   if(field->getFieldName().compare("display")!=0) return false;
-   FieldConstPtrArray fields = st->getFields();
-   int n = st->getNumberFields();
-   if(n!=4) return false;
-   // look at limit first
-   FieldConstPtr f = fields[3];
-   if(f->getFieldName().compare("limit")!=0) return false;
-   if(f->getType()!=structure) return false;
-   const Structure* s = static_cast<const Structure*>(f.get());
-   FieldConstPtrArray subfields = s->getFields();
-   n = s->getNumberFields();
-   if(n!=2) return false;
-   f = subfields[0];
-   if(f->getFieldName().compare("low")!=0) return false;
-   if(f->getType()!=scalar) return false;
-   const Scalar* sc = static_cast<const Scalar*>(f.get());
-   if(sc->getScalarType()!=pvDouble) return false;
-   f = subfields[1];
-   if(f->getFieldName().compare("high")!=0) return false;
-   if(f->getType()!=scalar) return false;
-   sc = static_cast<const Scalar*>(f.get());
-   if(sc->getScalarType()!=pvDouble) return false;
-   f = fields[0];
-   if(f->getFieldName().compare("description")!=0) return false;
-   if(f->getType()!=scalar) return false;
-   sc = static_cast<const Scalar*>(f.get());
-   if(sc->getScalarType()!=pvString) return false;
-   f = fields[1];
-   if(f->getFieldName().compare("format")!=0) return false;
-   if(f->getType()!=scalar) return false;
-   sc = static_cast<const Scalar*>(f.get());
-   if(sc->getScalarType()!=pvString) return false;
-   f = fields[2];
-   if(f->getFieldName().compare("units")!=0) return false;
-   if(f->getType()!=scalar) return false;
-   sc = static_cast<const Scalar*>(f.get());
-   if(sc->getScalarType()!=pvString) return false;
-   return true;
-}
-
-bool NTField::isAlarmLimit(FieldConstPtr field)
-{
-   if(field->getType()!=structure) return false;
-   const Structure *st = static_cast<const Structure *>(field.get());
-   if(field->getFieldName().compare("alarmLimit")!=0) return false;
-   FieldConstPtrArray fields = st->getFields();
-   int n = st->getNumberFields();
-   if(n!=4) return false;
+   StructureConstPtr structurePtr = static_pointer_cast<const Structure>(field);
+   FieldConstPtrArray fields = structurePtr->getFields();
+   StringArray names = structurePtr->getFieldNames();
+   size_t n = structurePtr->getNumberFields();
+   if(n!=5) return false;
    FieldConstPtr f = fields[0];
-   if(f->getFieldName().compare("highAlarm")!=0) return false;
+   if(names[0].compare("limitLow")!=0) return false;
    if(f->getType()!=scalar) return false;
-   const Scalar *sc = static_cast<const Scalar *>(f.get());
-   if(sc->getScalarType()!=pvDouble) return false;
+   ScalarConstPtr s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvDouble) return false;
    f = fields[1];
-   if(f->getFieldName().compare("highWarning")!=0) return false;
+   if(names[1].compare("limitHigh")!=0) return false;
    if(f->getType()!=scalar) return false;
-   sc = static_cast<const Scalar *>(f.get());
-   if(sc->getScalarType()!=pvDouble) return false;
+   s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvDouble) return false;
    f = fields[2];
-   if(f->getFieldName().compare("lowWarning")!=0) return false;
+   if(names[2].compare("description")!=0) return false;
    if(f->getType()!=scalar) return false;
-   sc = static_cast<const Scalar *>(f.get());
-   if(sc->getScalarType()!=pvDouble) return false;
+   s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvString) return false;
    f = fields[3];
-   if(f->getFieldName().compare("lowAlarm")!=0) return false;
+   if(names[3].compare("format")!=0) return false;
    if(f->getType()!=scalar) return false;
-   sc = static_cast<const Scalar *>(f.get());
-   if(sc->getScalarType()!=pvDouble) return false;
+   s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvString) return false;
+   f = fields[4];
+   if(names[4].compare("units")!=0) return false;
+   if(f->getType()!=scalar) return false;
+   s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvString) return false;
    return true;
 }
 
-bool NTField::isControl(FieldConstPtr field)
+bool NTField::isAlarmLimit(FieldConstPtr const & field)
 {
    if(field->getType()!=structure) return false;
-   const Structure *st = static_cast<const Structure *>(field.get());
-   if(field->getFieldName().compare("control")!=0) return false;
-   FieldConstPtrArray fields = st->getFields();
-   int n = st->getNumberFields();
-   if(n!=2) return false;
-   FieldConstPtr f = fields[1];
-   if(f->getFieldName().compare("minStep")!=0) return false;
+   StructureConstPtr structurePtr = static_pointer_cast<const Structure>(field);
+   FieldConstPtrArray fields = structurePtr->getFields();
+   StringArray names = structurePtr->getFieldNames();
+   size_t n = structurePtr->getNumberFields();
+   if(n!=10) return false;
+   FieldConstPtr f = fields[0];
+   if(names[0].compare("active")!=0) return false;
    if(f->getType()!=scalar) return false;
-   const Scalar* sc = static_cast<const Scalar*>(f.get());
-   if(sc->getScalarType()!=pvDouble) return false;
-   f = fields[0];
-   if(f->getFieldName().compare("limit")!=0) return false;
-   if(f->getType()!=structure) return false;
-   const Structure* s = static_cast<const Structure*>(f.get());
-   fields = s->getFields();
-   n = s->getNumberFields();
-   if(n!=2) return false;
-   f = fields[0];
-   if(f->getFieldName().compare("low")!=0) return false;
-   if(f->getType()!=scalar) return false;
-   sc = static_cast<const Scalar*>(f.get());
-   if(sc->getScalarType()!=pvDouble) return false;
+   ScalarConstPtr s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvDouble) return false;
    f = fields[1];
-   if(f->getFieldName().compare("high")!=0) return false;
+   if(names[1].compare("lowAlarmLimit")!=0) return false;
+   if(f->getType()!=scalar) return false;
+   f = fields[2];
+   if(names[2].compare("lowWarningLimit")!=0) return false;
+   if(f->getType()!=scalar) return false;
+   f = fields[3];
+   if(names[3].compare("highWarningLimit")!=0) return false;
+   if(f->getType()!=scalar) return false;
+   f = fields[4];
+   if(names[4].compare("highAlarmLimit")!=0) return false;
+   if(f->getType()!=scalar) return false;
+   f = fields[5];
+   if(names[5].compare("lowAlarmSeverity")!=0) return false;
+   if(f->getType()!=scalar) return false;
+   s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvInt) return false;
+   f = fields[6];
+   if(names[6].compare("lowWarningSeverity")!=0) return false;
+   if(f->getType()!=scalar) return false;
+   s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvInt) return false;
+   f = fields[7];
+   if(names[7].compare("highWarningSeverity")!=0) return false;
+   if(f->getType()!=scalar) return false;
+   s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvInt) return false;
+   f = fields[8];
+   if(names[8].compare("highAlarmSeverity")!=0) return false;
+   if(f->getType()!=scalar) return false;
+   s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvInt) return false;
+   f = fields[9];
+   if(names[9].compare("hystersis")!=0) return false;
    if(f->getType()!=scalar) return false;
-   sc = static_cast<const Scalar*>(f.get());
-   if(sc->getScalarType()!=pvDouble) return false;
    return true;
 }
 
-StructureConstPtr NTField::createEnumerated(String fieldName)
+bool NTField::isControl(FieldConstPtr const & field)
 {
-    return standardField->enumerated(fieldName);
+   if(field->getType()!=structure) return false;
+   StructureConstPtr structurePtr = static_pointer_cast<const Structure>(field);
+   FieldConstPtrArray fields = structurePtr->getFields();
+   StringArray names = structurePtr->getFieldNames();
+   size_t n = structurePtr->getNumberFields();
+   if(n!=3) return false;
+   FieldConstPtr f = fields[0];
+   if(names[0].compare("limitLow")!=0) return false;
+   if(f->getType()!=scalar) return false;
+   ScalarConstPtr s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvDouble) return false;
+   f = fields[1];
+   if(names[1].compare("limitHigh")!=0) return false;
+   if(f->getType()!=scalar) return false;
+   s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvDouble) return false;
+   f = fields[2];
+   if(names[2].compare("minStep")!=0) return false;
+   if(f->getType()!=scalar) return false;
+   s = static_pointer_cast<const Scalar>(f);
+   if(s->getScalarType()!=pvDouble) return false;
+   return true;
+}
+
+StructureConstPtr NTField::createEnumerated()
+{
+    return standardField->enumerated();
 }
 
 StructureConstPtr NTField::createTimeStamp()
@@ -229,13 +237,7 @@ StructureConstPtr NTField::createDisplay()
 
 StructureConstPtr NTField::createAlarmLimit()
 {
-    int numFields = 4;
-    FieldConstPtrArray fields = new FieldConstPtr[numFields];
-    fields[0] = fieldCreate->createScalar(String("highAlarm"),pvDouble);
-    fields[1] = fieldCreate->createScalar(String("highWarning"),pvDouble);
-    fields[2] = fieldCreate->createScalar(String("lowWarning"),pvDouble);
-    fields[3] = fieldCreate->createScalar(String("lowAlarm"),pvDouble);
-    return fieldCreate->createStructure(String("alarmLimit"),numFields,fields);
+    return standardField->doubleAlarm();
 }
 
 StructureConstPtr NTField::createControl()
@@ -243,35 +245,37 @@ StructureConstPtr NTField::createControl()
     return standardField->control();
 }
 
-StructureArrayConstPtr NTField::createEnumeratedArray(String fieldName)
+StructureArrayConstPtr NTField::createEnumeratedArray()
 {
-    StructureConstPtr st = createEnumerated(fieldName);
-    return fieldCreate->createStructureArray(fieldName,st);
+    return fieldCreate->createStructureArray(createEnumerated());
 }
 
-StructureArrayConstPtr NTField::createTimeStampArray(String fieldName)
+StructureArrayConstPtr NTField::createTimeStampArray()
 {
     StructureConstPtr st = createTimeStamp();
-    return fieldCreate->createStructureArray(fieldName,st);
+    return fieldCreate->createStructureArray(st);
 }
 
-StructureArrayConstPtr NTField::createAlarmArray(String fieldName)
+StructureArrayConstPtr NTField::createAlarmArray()
 {
     StructureConstPtr st = createAlarm();
-    return fieldCreate->createStructureArray(fieldName,st);
+    return fieldCreate->createStructureArray(st);
 }
 
-PVNTField *PVNTField::get()
+PVNTFieldPtr PVNTField::get()
 {
     static Mutex mutex;
-    static PVNTField *pvntstructureField = 0;
+    static PVNTFieldPtr pvntstructureField;
     Lock xx(mutex);
-    if(pvntstructureField==0) pvntstructureField = new PVNTField();
+    if(pvntstructureField.get()==NULL) {
+         pvntstructureField = PVNTFieldPtr(new PVNTField());
+    }
     return pvntstructureField;
 }
 
 PVNTField::PVNTField()
 : pvDataCreate(getPVDataCreate()),
+  standardField(getStandardField()),
   standardPVField(getStandardPVField()),
   ntstructureField(NTField::get())
 {
@@ -279,60 +283,60 @@ PVNTField::PVNTField()
 
 
 PVStructurePtr PVNTField::createEnumerated(
-    PVStructurePtr parent,
-    String fieldName,
-    StringArray choices,
-    int numberChoices)
+    StringArray const & choices)
 {
-    return standardPVField->enumerated(parent,fieldName,choices,numberChoices);
+    return standardPVField->enumerated(choices);
 }
 
-PVStructurePtr PVNTField::createTimeStamp(PVStructurePtr parent)
+PVStructurePtr PVNTField::createTimeStamp()
 {
-    return standardPVField->timeStamp(parent);
+    StructureConstPtr timeStamp = standardField->timeStamp();
+    return pvDataCreate->createPVStructure(timeStamp);
 }
 
-PVStructurePtr PVNTField::createAlarm(PVStructurePtr parent)
+PVStructurePtr PVNTField::createAlarm()
 {
-    return standardPVField->alarm(parent);
+    StructureConstPtr alarm = standardField->alarm();
+    return pvDataCreate->createPVStructure(alarm);
 }
 
-PVStructurePtr PVNTField::createDisplay(PVStructurePtr parent)
+PVStructurePtr PVNTField::createDisplay()
 {
-    return standardPVField->display(parent);
+    StructureConstPtr display = standardField->display();
+    return pvDataCreate->createPVStructure(display);
 }
 
-PVStructurePtr PVNTField::createAlarmLimit(PVStructurePtr parent)
+PVStructurePtr PVNTField::createAlarmLimit()
 {
     StructureConstPtr structure = NTField::get()->createAlarmLimit();
-    return pvDataCreate->createPVStructure(parent,structure);
+    return pvDataCreate->createPVStructure(structure);
 }
 
 
-PVStructurePtr PVNTField::createControl(PVStructurePtr parent)
+PVStructurePtr PVNTField::createControl()
 {
-    return standardPVField->control(parent);
+    StructureConstPtr control = standardField->control();
+    return pvDataCreate->createPVStructure(control);
 }
 
-PVStructureArray *PVNTField::createEnumeratedArray(
-    PVStructurePtr parent,String fieldName)
+PVStructureArrayPtr PVNTField::createEnumeratedArray()
 {
-    StructureArrayConstPtr sa = ntstructureField->createEnumeratedArray(fieldName);
-    return pvDataCreate->createPVStructureArray(parent,sa);
+    StructureArrayConstPtr sa =
+        ntstructureField->createEnumeratedArray();
+    return pvDataCreate->createPVStructureArray(sa);
 }
 
-PVStructureArray *PVNTField::createTimeStampArray(
-    PVStructurePtr parent,String fieldName)
+PVStructureArrayPtr PVNTField::createTimeStampArray()
 {
-    StructureArrayConstPtr sa = ntstructureField->createTimeStampArray(fieldName);
-    return pvDataCreate->createPVStructureArray(parent,sa);
+    StructureArrayConstPtr sa =
+         ntstructureField->createTimeStampArray();
+    return pvDataCreate->createPVStructureArray(sa);
 }
 
-PVStructureArray *PVNTField::createAlarmArray(
-    PVStructurePtr parent,String fieldName)
+PVStructureArrayPtr PVNTField::createAlarmArray()
 {
-    StructureArrayConstPtr sa = ntstructureField->createAlarmArray(fieldName);
-    return pvDataCreate->createPVStructureArray(parent,sa);
+    StructureArrayConstPtr sa = ntstructureField->createAlarmArray();
+    return pvDataCreate->createPVStructureArray(sa);
 }
 
 }}
diff --git a/src/nt/ntfield.h b/src/nt/ntfield.h
index b495d40..e7fc73f 100644
--- a/src/nt/ntfield.h
+++ b/src/nt/ntfield.h
@@ -22,13 +22,23 @@ namespace epics { namespace pvData {
  * @author mrk
  * 
  */
-class NTField: NoDefaultMethods {
+
+typedef std::tr1::shared_ptr<epics::pvData::StringArray> StringArrayPtr;
+
+class NTField;
+typedef std::tr1::shared_ptr<NTField> NTFieldPtr;
+
+class PVNTField;
+typedef std::tr1::shared_ptr<PVNTField> PVNTFieldPtr;
+
+class NTField {
 public:
+    POINTER_DEFINITIONS(NTField);
     /**
      * get the single implementation of this class.
      * @return the implementation
      */
-    static NTField * get();
+    static NTFieldPtr get();
     /**
      * destructor
      */
@@ -38,44 +48,43 @@ public:
      * @param field The field to test.
      * @return (false,true) if field (is not,is) an enumerated structure.
      */
-    bool isEnumerated(FieldConstPtr field);
+    bool isEnumerated(FieldConstPtr const & field);
     /**
      * Is field a timeStamp structure.
      * @param field The field to test.
      * @return (false,true) if field (is not,is) a timeStamp structure.
      */
-    bool isTimeStamp(FieldConstPtr field);
+    bool isTimeStamp(FieldConstPtr const & field);
     /**
      * Is field an alarm structure.
      * @param field The field to test.
      * @return (false,true) if field (is not,is) an alarm structure.
      */
-    bool isAlarm(FieldConstPtr field);
+    bool isAlarm(FieldConstPtr const & field);
     /**
      * Is field a display structure.
      * @param field The field to test.
      * @return (false,true) if field (is not,is) a display structure.
      */
-    bool isDisplay(FieldConstPtr field);
+    bool isDisplay(FieldConstPtr const & field);
     /**
      * Is field an alarmLimit structure.
      * @param field The field to test.
      * @return (false,true) if field (is not,is) an alarmLimit structure.
      */
-    bool isAlarmLimit(FieldConstPtr field);
+    bool isAlarmLimit(FieldConstPtr const & field);
     /**
      * Is field a control structure.
      * @param field The field to test.
      * @return (false,true) if field (is not,is) a control structure.
      */
-    bool isControl(FieldConstPtr field);
+    bool isControl(FieldConstPtr const & field);
 
     /**
      * Create an enumerated structure.
-     * @param fieldName The fieldName for the structure.
      * @return an enumerated structure.
      */
-    StructureConstPtr createEnumerated(String fieldName);
+    StructureConstPtr createEnumerated();
     /**
      * Create a timeStamp structure.
      * @return a timeStamp structure.
@@ -104,26 +113,23 @@ public:
 
     /**
      * Create an array of enumerated structures.
-     * @param fieldName The fieldName for the array.
      * @return an array of enumerated structures.
      */
-    StructureArrayConstPtr createEnumeratedArray(String fieldName);
+    StructureArrayConstPtr createEnumeratedArray();
     /**
      * Create an array of timeStamp structures.
-     * @param fieldName The fieldName for the array.
      * @return an array of timeStamp structures.
      */
-    StructureArrayConstPtr createTimeStampArray(String fieldName);
+    StructureArrayConstPtr createTimeStampArray();
     /**
      * Create an array of alarm structures.
-     * @param fieldName The fieldName for the array.
      * @return an array of alarm structures.
      */
-    StructureArrayConstPtr createAlarmArray(String fieldName);
+    StructureArrayConstPtr createAlarmArray();
 private:
     NTField();
-    FieldCreate *fieldCreate;
-    StandardField *standardField;
+    FieldCreatePtr fieldCreate;
+    StandardFieldPtr standardField;
 };
 
 /**
@@ -131,90 +137,72 @@ private:
  * @author mrk
  * 
  */
-class PVNTField: NoDefaultMethods {
+class PVNTField {
 public:
+    POINTER_DEFINITIONS(PVNTField);
     /**
      * get the single implementation of this class.
      * @return the implementation
      */
-    static PVNTField * get();
+    static PVNTFieldPtr get();
     /**
      * destructor
      */
     ~PVNTField() {}
     /**
      * Create an enumerated PVStructure.
-     * @param parent The parent structure.
-     * @param fieldName The fieldName for the structure.
      * @param choices The array of choices.
-     * @param numberChoices The number of choices.
      * @return an enumerated PVStructure..
      */
     PVStructurePtr createEnumerated(
-        PVStructurePtr parent,
-        String fieldName,
-        StringArray choices,
-        int numberChoices);
+        StringArray const & choices);
     /**
      * Create a timeStamp PVStructure.
-     * @param parent The parent structure.
      * @return a timeStamp PVStructure..
      */
-    PVStructurePtr createTimeStamp(PVStructurePtr parent);
+    PVStructurePtr createTimeStamp();
     /**
      * Create an alarm PVStructure.
-     * @param parent The parent structure.
      * @return an alarm PVStructure..
      */
-    PVStructurePtr createAlarm(PVStructurePtr parent);
+    PVStructurePtr createAlarm();
     /**
      * Create a display PVStructure.
-     * @param parent The parent structure.
      * @return a display PVStructure..
      */
-    PVStructurePtr createDisplay(PVStructurePtr parent);
+    PVStructurePtr createDisplay();
     /**
      * Create an alarmLimit PVStructure.
-     * @param parent The parent structure.
      * @return an alarmLimit PVStructure..
      */
-    PVStructurePtr createAlarmLimit(PVStructurePtr parent);
+    PVStructurePtr createAlarmLimit();
     /**
      * Create a control PVStructure.
-     * @param parent The parent structure.
      * @return a control PVStructure..
      */
-    PVStructurePtr createControl(PVStructurePtr parent);
+    PVStructurePtr createControl();
 
     /**
      * Create an enumerated PVStructureArray.
-     * @param parent The parent structure.
-     * @param fieldName The fieldName for the structure.
      * @return an enumerated PVStructureArray..
      */
-    PVStructureArray * createEnumeratedArray(
-        PVStructurePtr parent,String fieldName);
+    PVStructureArrayPtr createEnumeratedArray();
     /**
      * Create a timeStamp PVStructureArray.
-     * @param parent The parent structure.
-     * @param fieldName The fieldName for the structure.
      * @return a timeStamp PVStructureArray
      */
-    PVStructureArray * createTimeStampArray(
-        PVStructurePtr parent,String fieldName);
+    PVStructureArrayPtr createTimeStampArray();
     /**
      * Create an alarm PVStructureArray.
-     * @param parent The parent structure.
-     * @param fieldName The fieldName for the structure.
      * @return an alarm PVStructureArray..
      */
-    PVStructureArray * createAlarmArray(
-        PVStructurePtr parent,String fieldName);
+    PVStructureArrayPtr createAlarmArray();
 private:
     PVNTField();
-    PVDataCreate *pvDataCreate;
-    StandardPVField *standardPVField;
-    NTField *ntstructureField;
+    PVDataCreatePtr pvDataCreate;
+    StandardFieldPtr standardField;
+    StandardPVFieldPtr standardPVField;
+    NTFieldPtr ntstructureField;
 };
 
 }}
diff --git a/src/nt/ntnameValue.h b/src/nt/ntnameValue.h
index 81f2257..c4256d3 100644
--- a/src/nt/ntnameValue.h
+++ b/src/nt/ntnameValue.h
@@ -17,6 +17,9 @@ namespace epics { namespace pvData {
  *
  */
 
+class NTNameValue 
+typedef std::tr1::shared_ptr<NTNameValue> NTNameValuePtr;
+
 class NTNameValue 
 {
 public:
@@ -26,7 +29,7 @@ public:
      * @param pvStructure The pvStructure to test.
      * @return (false,true) if (is not, is) an NTNameValue.
      */
-    static bool isNTNameValue(PVStructurePtr pvStructure);
+    static bool isNTNameValue(PVStructurePtr const & pvStructure);
     /**
      * Create an  NTNameValue pvStructure.
      * @param hasFunction Create a PVString field named function.
@@ -34,14 +37,14 @@ public:
      * @param hasAlarm Create an alarm structure field.
      * @return a NTNameValue pvStructure.
      */
-    static PVStructure::shared_pointer create(
+    static PVStructurePtr create(
         bool hasFunction,bool hasTimeStamp, bool hasAlarm);
     /**
      * Constructor
      * @param pvStructure The pvStructure to which to attach.
      * @return A NTNameValue that is attached to the pvStructure
      */
-    NTNameValue(PVStructure::shared_pointer const & pvStructure);
+    NTNameValue(PVStructurePtr const & pvStructure);
     /**
      * Destructor
      */
@@ -50,7 +53,7 @@ public:
      * Get the function field.
      * @return The pvString or null if no function field.
      */
-    PVString* getFunction();
+    PVStringPtr getFunction();
     /**
      * Attach a pvTimeStamp.
      * @param pvTimeStamp The pvTimeStamp that will be attached.
@@ -67,7 +70,7 @@ public:
      * Get the pvStructure.
      * @return PVStructurePtr.
      */
-    PVStructurePtr getPVStructure(){return pvNTNameValue.get();}
+    PVStructurePtr getPVStructure(){return pvNTNameValue;}
     /**
      * Get the timeStamp.
      * @return PVStructurePtr which may be null.
@@ -82,19 +85,19 @@ public:
      * Get the string array on names.
      * @return The array of names.
      */
-    PVStringArray *getNames();
+    PVStringArrayPtr getNames();
     /**
      * Get the string array on values.
      * @return The array of values.
      */
-    PVStringArray *getValues();
+    PVStringArrayPtr getValues();
 private:
-    PVStructure::shared_pointer pvNTNameValue;
-    PVString * pvFunction;
+    PVStructurePtr pvNTNameValue;
+    PVStringPtr pvFunction;
     PVStructurePtr pvTimeStamp;
     PVStructurePtr pvAlarm;
-    PVStringArray *pvNames;
-    PVStringArray *pvValues;
+    PVStringArrayPtr pvNames;
+    PVStringArrayPtr pvValues;
 };
 
 }}
diff --git a/src/nt/nttable.h b/src/nt/nttable.h
index b3ac1e3..dd7e54f 100644
--- a/src/nt/nttable.h
+++ b/src/nt/nttable.h
@@ -17,6 +17,9 @@ namespace epics { namespace pvData {
  *
  */
 
+class NTTable
+typedef std::tr1::shared_ptr<NTTable> NTTablePtr;
+
 class NTTable
 {
 public:
@@ -26,7 +29,7 @@ public:
      * @param pvStructure The pvStructure to test.
      * @return (false,true) if (is not, is) an NTNameValuePair.
      */
-    static bool isNTTable(PVStructurePtr pvStructure);
+    static bool isNTTable(PVStructurePtr const &pvStructure);
     /**
      * Create an  NTTable pvStructure.
      * @param hasFunction Create a PVString field named function.
@@ -36,16 +39,16 @@ public:
      * @param valueFields The fields that follow the label field.
      * @return an NTTable pvStructure.
      */
-    static PVStructure::shared_pointer create(
+    static PVStructurePtr create(
         bool hasFunction,bool hasTimeStamp, bool hasAlarm,
-        int numberValues,
-        FieldConstPtrArray valueFields);
+        size_t numberValues,
+        FieldConstPtrArray const &valueFields);
     /**
      * Constructor
      * @param pvStructure The pvStructure to which to attach.
      * @return A NTTable that is attached to the pvStructure
      */
-    NTTable(PVStructure::shared_pointer const & pvStructure);
+    NTTable(PVStructurePtr const & pvStructure);
     /**
      * Destructor
      */
@@ -54,7 +57,7 @@ public:
      * Get the function field.
      * @return The pvString or null if no function field.
      */
-    PVString *getFunction();
+    PVStringPtr getFunction();
      /**
       * Attach a pvTimeStamp.
       * @param pvTimeStamp The pvTimeStamp that will be attached.
@@ -71,7 +74,7 @@ public:
      * Get the pvStructure.
      * @return PVStructurePtr.
      */
-    PVStructurePtr getPVStructure(){return pvNTTable.get();}
+    PVStructurePtr getPVStructure(){return pvNTTable;}
     /**
      * Get the timeStamp.
      * @return PVStructurePtr which may be null.
@@ -86,7 +89,7 @@ public:
      * Get the label field.
      * @return The pvStringArray for the label.
      */
-    PVStringArray *getLabel();
+    PVStringArrayPtr getLabel();
     /**
      * Get the the number of fields that follow the label field.
      * @return The number of fields.
@@ -105,12 +108,12 @@ public:
      */
     PVFieldPtr getPVField(int index);
 private:
-    PVStructure::shared_pointer pvNTTable;
-    PVString *pvFunction;
+    PVStructurePtr pvNTTable;
+    PVStringPtr pvFunction;
     PVStructurePtr pvTimeStamp;
     PVStructurePtr pvAlarm;
-    PVStringArray *pvLabel;
-    int offsetFields;
+    PVStringArrayPtr pvLabel;
+    size_t offsetFields;
 };
 
 }}