diff --git a/src/factory/PVStructure.cpp b/src/factory/PVStructure.cpp
index aba99bd..14a75c4 100644
--- a/src/factory/PVStructure.cpp
+++ b/src/factory/PVStructure.cpp
@@ -104,9 +104,9 @@ const PVFieldPtrArray & PVStructure::getPVFields() const
     return pvFields;
 }
 
-PVFieldPtr  PVStructure::getSubField(string const &fieldName) const
+PVFieldPtr  PVStructure::getSubField(const char * fieldName) const
 {
-    PVField * field = getSubFieldImpl(fieldName.c_str(), false);
+    PVField * field = getSubFieldImpl(fieldName, false);
     if (field)
        return field->shared_from_this();
     else
diff --git a/src/pv/pvData.h b/src/pv/pvData.h
index 2c6d128..dd8d9b5 100644
--- a/src/pv/pvData.h
+++ b/src/pv/pvData.h
@@ -702,7 +702,12 @@ public:
      * @param fieldName The name of the field.
      * @return Pointer to the field or null if field does not exist.
      */
-    PVFieldPtr getSubField(std::string const &fieldName) const;
+    FORCE_INLINE PVFieldPtr getSubField(std::string const &fieldName) const
+    {
+        return getSubField(fieldName.c_str());
+    }
+
+    PVFieldPtr getSubField(const char *fieldName) const;
 
     /**
      * Get a subfield with the specified name.