diff --git a/include/verilated.h b/include/verilated.h
index e7988eea3..541457c62 100644
--- a/include/verilated.h
+++ b/include/verilated.h
@@ -145,7 +145,7 @@ public:
 # define VL_CELL(instname,type)		///< Declare a cell, ala SP_CELL
 
 /// Declare a module, ala SC_MODULE
-# define VL_MODULE(modname)		struct modname : public VerilatedModule
+# define VL_MODULE(modname)		class modname : public VerilatedModule
 
 /// Constructor, ala SC_CTOR
 # define VL_CTOR(modname)		modname(const char* __VCname="")
@@ -216,9 +216,8 @@ public:  // But internals only - called from VerilatedModule's
 //===========================================================================
 /// Verilator global static information class
 
-struct Verilated {
+class Verilated {
     // MEMBERS
-private:
     // Slow path variables
     static VerilatedVoidCb  s_flushCb;		///< Flush callback function
 
diff --git a/include/verilated_syms.h b/include/verilated_syms.h
index f310f12ef..81957b4d4 100644
--- a/include/verilated_syms.h
+++ b/include/verilated_syms.h
@@ -93,7 +93,8 @@ public:
 //======================================================================
 /// Types
 
-struct VerilatedVarNameMap : public map<const char*, VerilatedVar, VerilatedCStrCmp> {
+class VerilatedVarNameMap : public map<const char*, VerilatedVar, VerilatedCStrCmp> {
+public:
     VerilatedVarNameMap() {}
     ~VerilatedVarNameMap() {}
 };
diff --git a/include/verilated_vpi.h b/include/verilated_vpi.h
index 53e8cb6ce..1c1a123f3 100644
--- a/include/verilated_vpi.h
+++ b/include/verilated_vpi.h
@@ -297,7 +297,7 @@ struct VerilatedVpiTimedCbsCmp {
     }
 };
 
-struct VerilatedVpiError;
+class VerilatedVpiError;
 
 class VerilatedVpi {
     enum { CB_ENUM_MAX_VALUE = cbAtEndOfSimTime+1 };	// Maxium callback reason
diff --git a/src/V3Options.cpp b/src/V3Options.cpp
index e901b7836..caecbb4e6 100644
--- a/src/V3Options.cpp
+++ b/src/V3Options.cpp
@@ -46,7 +46,8 @@
 //######################################################################
 // V3 Internal state
 
-struct V3OptionsImp {
+class V3OptionsImp {
+public:
     // TYPES
     typedef std::map<string,set<string> > DirMap;	// Directory listing
 
@@ -91,6 +92,7 @@ struct V3OptionsImp {
 	}
     }
     V3OptionsImp() {}
+    ~V3OptionsImp() {}
 };
 
 void V3Options::addIncDirUser(const string& incdir) {
diff --git a/src/V3PreProc.cpp b/src/V3PreProc.cpp
index 01638efa0..35b0b2426 100644
--- a/src/V3PreProc.cpp
+++ b/src/V3PreProc.cpp
@@ -107,7 +107,8 @@ public:
 //*************************************************************************
 // Data for a preprocessor instantiation.
 
-struct V3PreProcImp : public V3PreProc {
+class V3PreProcImp : public V3PreProc {
+public:
     // TYPES
     typedef std::map<string,V3Define> DefinesMap;
     typedef V3InFilter::StrList StrList;