diff --git a/CheckHeaders.cpp b/CheckHeaders.cpp
index 9d8eeb060..a8d9eff6e 100644
--- a/CheckHeaders.cpp
+++ b/CheckHeaders.cpp
@@ -47,7 +47,7 @@ CheckHeaders::~CheckHeaders()
 
 void CheckHeaders::WarningHeaderWithImplementation()
 {
-    for (TOKEN *tok = _tokenizer->tokens(); tok; tok = tok->next)
+    for ( const TOKEN *tok = _tokenizer->tokens(); tok; tok = tok->next)
     {
         // Only interested in included file
         if (tok->FileIndex == 0)
@@ -82,7 +82,7 @@ void CheckHeaders::WarningHeaderWithImplementation()
 void CheckHeaders::WarningIncludeHeader()
 {
     // Including..
-    for (TOKEN *includetok = _tokenizer->tokens(); includetok; includetok = includetok->next)
+    for ( const TOKEN *includetok = _tokenizer->tokens(); includetok; includetok = includetok->next)
     {
         if (strcmp(includetok->str, "#include") != 0)
             continue;
@@ -111,7 +111,7 @@ void CheckHeaders::WarningIncludeHeader()
 
         // Extract classes and names in the header..
         int indentlevel = 0;
-        for ( TOKEN *tok1 = _tokenizer->tokens(); tok1; tok1 = tok1->next )
+        for ( const TOKEN *tok1 = _tokenizer->tokens(); tok1; tok1 = tok1->next )
         {
             if ( tok1->FileIndex != hfile )
                 continue;
@@ -205,7 +205,7 @@ void CheckHeaders::WarningIncludeHeader()
         // Check if the extracted names are used...
         bool Needed = false;
         bool NeedDeclaration = false;
-        for (TOKEN *tok1 = _tokenizer->tokens(); tok1; tok1 = tok1->next)
+        for ( const TOKEN *tok1 = _tokenizer->tokens(); tok1; tok1 = tok1->next)
         {
             if (tok1->FileIndex != includetok->FileIndex)
                 continue;
diff --git a/CheckOther.cpp b/CheckOther.cpp
index 26e187ebe..5bae59368 100644
--- a/CheckOther.cpp
+++ b/CheckOther.cpp
@@ -377,7 +377,7 @@ void CheckOther::CheckUnsignedDivision()
 {
     // Check for "ivar / uvar" and "uvar / ivar"
     std::map<std::string, char> varsign;
-    for ( TOKEN *tok = _tokenizer->tokens(); tok; tok = tok->next )
+    for ( const TOKEN *tok = _tokenizer->tokens(); tok; tok = tok->next )
     {
         if ( Match(tok, "[{};(,] %type% %var% [;=,)]") )
         {
diff --git a/tokenize.cpp b/tokenize.cpp
index 02f0425e0..62bb2477d 100644
--- a/tokenize.cpp
+++ b/tokenize.cpp
@@ -73,7 +73,7 @@ TOKEN *Tokenizer::_gettok(TOKEN *tok, int index)
 }
 //---------------------------------------------------------------------------
 
-TOKEN *Tokenizer::tokens()
+const TOKEN *Tokenizer::tokens() const
 {
     return _tokens;
 }
diff --git a/tokenize.h b/tokenize.h
index 9310d5fe3..19508fbef 100644
--- a/tokenize.h
+++ b/tokenize.h
@@ -94,7 +94,7 @@ public:
     const TOKEN *GetFunctionTokenByName( const char funcname[] ) const;
     void CheckGlobalFunctionUsage(const std::vector<std::string> &filenames);
     void settings( const Settings &settings );
-    TOKEN *tokens();
+    const TOKEN *tokens() const;
 private:
 
     struct DefineSymbol