diff --git a/Source/cmDocumentation.cxx b/Source/cmDocumentation.cxx
index 840b5c084..a03d267c0 100644
--- a/Source/cmDocumentation.cxx
+++ b/Source/cmDocumentation.cxx
@@ -1424,7 +1424,7 @@ void cmDocumentation::SetSection(const cmDocumentationEntry* header,
 }
 
 //----------------------------------------------------------------------------
-const char* cmDocumentation::GetNameString()
+const char* cmDocumentation::GetNameString() const
 {
   if(this->NameString.length() > 0)
     {
@@ -1437,7 +1437,7 @@ const char* cmDocumentation::GetNameString()
 }
 
 //----------------------------------------------------------------------------
-bool cmDocumentation::IsOption(const char* arg)
+bool cmDocumentation::IsOption(const char* arg) const
 {
   return ((arg[0] == '-') || (strcmp(arg, "/V") == 0) || 
           (strcmp(arg, "/?") == 0));
diff --git a/Source/cmDocumentation.h b/Source/cmDocumentation.h
index 53ced4484..0aa81de93 100644
--- a/Source/cmDocumentation.h
+++ b/Source/cmDocumentation.h
@@ -155,8 +155,8 @@ private:
                   const cmDocumentationEntry* section,
                   const cmDocumentationEntry* footer,
                   std::vector<cmDocumentationEntry>&);
-  const char* GetNameString();
-  bool IsOption(const char* arg);
+  const char* GetNameString() const;
+  bool IsOption(const char* arg) const;
 
   std::string NameString;
   std::vector<cmDocumentationEntry> NameSection;