diff --git a/src/factory/Compare.cpp b/src/factory/Compare.cpp
index 06b4e27..19c0230 100644
--- a/src/factory/Compare.cpp
+++ b/src/factory/Compare.cpp
@@ -91,14 +91,14 @@ bool operator==(const Structure& a, const Structure& b)
         return false;
 
     // std::equals does not work, since FieldConstPtrArray is an array of shared_pointers
-    FieldConstPtrArray af = a.getFields();
-    FieldConstPtrArray bf = b.getFields();
+    FieldConstPtrArray const & af = a.getFields();
+    FieldConstPtrArray const & bf = b.getFields();
     for (size_t i = 0; i < nflds; i++)
         if (*(af[i].get()) != *(bf[i].get()))
             return false;
 
-    StringArray an = a.getFieldNames();
-    StringArray bn = b.getFieldNames();
+    StringArray const & an = a.getFieldNames();
+    StringArray const & bn = b.getFieldNames();
     return std::equal( an.begin(), an.end(), bn.begin() );
 }
 
@@ -118,14 +118,14 @@ bool operator==(const Union& a, const Union& b)
         return false;
 
     // std::equals does not work, since FieldConstPtrArray is an array of shared_pointers
-    FieldConstPtrArray af = a.getFields();
-    FieldConstPtrArray bf = b.getFields();
+    FieldConstPtrArray const & af = a.getFields();
+    FieldConstPtrArray const & bf = b.getFields();
     for (size_t i = 0; i < nflds; i++)
         if (*(af[i].get()) != *(bf[i].get()))
             return false;
 
-    StringArray an = a.getFieldNames();
-    StringArray bn = b.getFieldNames();
+    StringArray const & an = a.getFieldNames();
+    StringArray const & bn = b.getFieldNames();
     return std::equal( an.begin(), an.end(), bn.begin() );
 }
 
diff --git a/src/factory/Convert.cpp b/src/factory/Convert.cpp
index 15a700a..026ccfe 100644
--- a/src/factory/Convert.cpp
+++ b/src/factory/Convert.cpp
@@ -282,8 +282,8 @@ bool Convert::isCopyScalarArrayCompatible(ScalarArrayConstPtr const &fromArray,
 bool Convert::isCopyStructureCompatible(
     StructureConstPtr const &fromStruct, StructureConstPtr const &toStruct)
 {
-    FieldConstPtrArray fromFields = fromStruct->getFields();
-    FieldConstPtrArray toFields = toStruct->getFields();
+    FieldConstPtrArray const & fromFields = fromStruct->getFields();
+    FieldConstPtrArray const & toFields = toStruct->getFields();
     size_t length = fromStruct->getNumberFields();
     if(length!=toStruct->getNumberFields()) return false;
     for(size_t i=0; i<length; i++) {
diff --git a/src/factory/FieldCreateFactory.cpp b/src/factory/FieldCreateFactory.cpp
index ff7feb7..daaeaff 100644
--- a/src/factory/FieldCreateFactory.cpp
+++ b/src/factory/FieldCreateFactory.cpp
@@ -989,8 +989,8 @@ StructureConstPtr FieldCreate::appendField(
     string const & fieldName,
     FieldConstPtr const & field) const
 {
-    StringArray oldNames = structure->getFieldNames();
-    FieldConstPtrArray oldFields = structure->getFields();
+    StringArray const & oldNames = structure->getFieldNames();
+    FieldConstPtrArray const & oldFields = structure->getFields();
     size_t oldLen = oldNames.size();
     StringArray newNames(oldLen+1);
     FieldConstPtrArray newFields(oldLen+1);
@@ -1008,8 +1008,8 @@ StructureConstPtr FieldCreate::appendFields(
     StringArray const & fieldNames,
     FieldConstPtrArray const & fields) const
 {
-    StringArray oldNames = structure->getFieldNames();
-    FieldConstPtrArray oldFields = structure->getFields();
+    StringArray const & oldNames = structure->getFieldNames();
+    FieldConstPtrArray const & oldFields = structure->getFields();
     size_t oldLen = oldNames.size();
     size_t extra = fieldNames.size();
     StringArray newNames(oldLen+extra);
diff --git a/src/factory/PVDataCreateFactory.cpp b/src/factory/PVDataCreateFactory.cpp
index e88543c..3a5c714 100644
--- a/src/factory/PVDataCreateFactory.cpp
+++ b/src/factory/PVDataCreateFactory.cpp
@@ -527,7 +527,7 @@ PVFieldPtr PVDataCreate::createPVField(PVFieldPtr const & fieldToClone)
              PVStructurePtr pvStructure
                    = static_pointer_cast<PVStructure>(fieldToClone);
              StringArray const & fieldNames = pvStructure->getStructure()->getFieldNames();
-             PVFieldPtrArray pvFieldPtrArray = pvStructure->getPVFields();
+             PVFieldPtrArray const & pvFieldPtrArray = pvStructure->getPVFields();
              return createPVStructure(fieldNames,pvFieldPtrArray);
          }
      case structureArray:
diff --git a/src/factory/PVField.cpp b/src/factory/PVField.cpp
index fe6ed82..20db350 100644
--- a/src/factory/PVField.cpp
+++ b/src/factory/PVField.cpp
@@ -121,7 +121,7 @@ void PVField::computeOffset(const PVField   *  pvField) {
     }
     size_t offset = 0;
     size_t nextOffset = 1;
-    PVFieldPtrArray  pvFields = pvTop->getPVFields();
+    const PVFieldPtrArray & pvFields = pvTop->getPVFields();
     for(size_t i=0; i < pvTop->getStructure()->getNumberFields(); i++) {
         offset = nextOffset;
         PVField *pvField = pvFields[i].get();
@@ -153,7 +153,7 @@ void PVField::computeOffset(const PVField   *  pvField,size_t offset) {
     size_t beginOffset = offset;
     size_t nextOffset = offset + 1;
     const PVStructure *pvStructure = static_cast<const PVStructure *>(pvField);
-    const PVFieldPtrArray  pvFields = pvStructure->getPVFields();
+    const PVFieldPtrArray & pvFields = pvStructure->getPVFields();
     for(size_t i=0; i < pvStructure->getStructure()->getNumberFields(); i++) {
         offset = nextOffset;
         PVField *pvSubField = pvFields[i].get();
diff --git a/src/factory/PVStructure.cpp b/src/factory/PVStructure.cpp
index c08195a..e53e25f 100644
--- a/src/factory/PVStructure.cpp
+++ b/src/factory/PVStructure.cpp
@@ -55,8 +55,8 @@ PVStructure::PVStructure(StructureConstPtr const & structurePtr)
   extendsStructureName("")
 {
     size_t numberFields = structurePtr->getNumberFields();
-    FieldConstPtrArray fields = structurePtr->getFields();
-    StringArray fieldNames = structurePtr->getFieldNames();
+    FieldConstPtrArray const & fields = structurePtr->getFields();
+    StringArray const & fieldNames = structurePtr->getFieldNames();
 //    PVFieldPtrArray * xxx = const_cast<PVFieldPtrArray *>(&pvFields);
     pvFields.reserve(numberFields);
     PVDataCreatePtr pvDataCreate = getPVDataCreate();
@@ -76,7 +76,7 @@ PVStructure::PVStructure(StructureConstPtr const & structurePtr,
   extendsStructureName("")
 {
     size_t numberFields = structurePtr->getNumberFields();
-    StringArray fieldNames = structurePtr->getFieldNames();
+    StringArray const & fieldNames = structurePtr->getFieldNames();
     pvFields.reserve(numberFields);
     for(size_t i=0; i<numberFields; i++) {
         pvFields.push_back(pvs[i]);
@@ -342,7 +342,7 @@ static PVFieldPtr findSubField(
             restOfName = fieldName.substr(index+1);
         }
     }
-    PVFieldPtrArray  pvFields = pvStructure->getPVFields();
+    PVFieldPtrArray const & pvFields = pvStructure->getPVFields();
     PVFieldPtr pvField;
     size_t numFields = pvStructure->getStructure()->getNumberFields();
     for(size_t i=0; i<numFields; i++) {
diff --git a/src/factory/StandardField.cpp b/src/factory/StandardField.cpp
index d3009fa..57ffa42 100644
--- a/src/factory/StandardField.cpp
+++ b/src/factory/StandardField.cpp
@@ -89,9 +89,9 @@ StructureConstPtr StandardField::createProperties(string id,FieldConstPtr field,
         }
         if(type==structure) {
             StructureConstPtr structurePtr = static_pointer_cast<const Structure>(field);
-            StringArray names = structurePtr->getFieldNames();
+            StringArray const & names = structurePtr->getFieldNames();
             if(names.size()==2) {
-                FieldConstPtrArray fields = structurePtr->getFields();
+                FieldConstPtrArray const & fields = structurePtr->getFields();
                 FieldConstPtr first = fields[0];
                 FieldConstPtr second = fields[1];
                 string nameFirst = names[0];
diff --git a/src/property/pvEnumerated.cpp b/src/property/pvEnumerated.cpp
index b23a952..0ccee32 100644
--- a/src/property/pvEnumerated.cpp
+++ b/src/property/pvEnumerated.cpp
@@ -76,7 +76,7 @@ string PVEnumerated::getChoice()
     }
     size_t index = pvIndex->get();
     const PVStringArray::const_svector& data(pvChoices->view());
-    if(index<0 || index>=data.size()) {
+    if(/*index<0 ||*/ index>=data.size()) {
         string nullString;
         return nullString;
     }