diff --git a/lib/settings.cpp b/lib/settings.cpp
index 4a09d6632..16bc139f6 100644
--- a/lib/settings.cpp
+++ b/lib/settings.cpp
@@ -54,7 +54,7 @@ void Settings::autoDealloc(std::istream &istr)
             continue;
 
         // Add classname to list
-        _autoDealloc.push_back(line);
+        _autoDealloc.insert(line);
     }
 }
 
@@ -116,12 +116,12 @@ bool Settings::isSuppressed(const std::string &errorId, const std::string &file,
 
 void Settings::addAutoAllocClass(const std::string &name)
 {
-    _autoDealloc.push_back(name);
+    _autoDealloc.insert(name);
 }
 
 bool Settings::isAutoDealloc(const char classname[]) const
 {
-    return (std::find(_autoDealloc.begin(), _autoDealloc.end(), classname) != _autoDealloc.end());
+    return (_autoDealloc.find(classname) != _autoDealloc.end());
 }
 
 
diff --git a/lib/settings.h b/lib/settings.h
index 3d1af764f..5ee008b03 100644
--- a/lib/settings.h
+++ b/lib/settings.h
@@ -23,6 +23,7 @@
 #include <string>
 #include <istream>
 #include <map>
+#include <set>
 
 /// @addtogroup Core
 /// @{
@@ -37,7 +38,7 @@ class Settings
 {
 private:
     /** classes that are automaticly deallocated */
-    std::list<std::string> _autoDealloc;
+    std::set<std::string> _autoDealloc;
 
     /** Code to append in the checks */
     std::string _append;