diff --git a/src/settings.cpp b/src/settings.cpp
index 56afa613..91ea9c58 100644
--- a/src/settings.cpp
+++ b/src/settings.cpp
@@ -985,39 +985,38 @@ void Settings::clearDefaultsNoLock()
 }
 
 
-void Settings::registerChangedCallback(std::string name,
-	setting_changed_callback cbf, void *userdata)
+void Settings::registerChangedCallback(const std::string &name,
+	SettingsChangedCallback cbf, void *userdata)
 {
-	MutexAutoLock lock(m_callbackMutex);
+	MutexAutoLock lock(m_callback_mutex);
 	m_callbacks[name].push_back(std::make_pair(cbf, userdata));
 }
 
-void Settings::deregisterChangedCallback(std::string name, setting_changed_callback cbf, void *userdata)
+void Settings::deregisterChangedCallback(const std::string &name,
+	SettingsChangedCallback cbf, void *userdata)
 {
-	MutexAutoLock lock(m_callbackMutex);
-	std::map<std::string, std::vector<std::pair<setting_changed_callback, void*> > >::iterator iterToVector = m_callbacks.find(name);
-	if (iterToVector != m_callbacks.end())
-	{
-		std::vector<std::pair<setting_changed_callback, void*> > &vector = iterToVector->second;
+	MutexAutoLock lock(m_callback_mutex);
+	SettingsCallbackMap::iterator it_cbks = m_callbacks.find(name);
 
-		std::vector<std::pair<setting_changed_callback, void*> >::iterator position =
-			std::find(vector.begin(), vector.end(), std::make_pair(cbf, userdata));
+	if (it_cbks != m_callbacks.end()) {
+		SettingsCallbackList &cbks = it_cbks->second;
 
-		if (position != vector.end())
-			vector.erase(position);
+		SettingsCallbackList::iterator position =
+			std::find(cbks.begin(), cbks.end(), std::make_pair(cbf, userdata));
+
+		if (position != cbks.end())
+			cbks.erase(position);
 	}
 }
 
-void Settings::doCallbacks(const std::string name)
+void Settings::doCallbacks(const std::string &name) const
 {
-	MutexAutoLock lock(m_callbackMutex);
-	std::map<std::string, std::vector<std::pair<setting_changed_callback, void*> > >::iterator iterToVector = m_callbacks.find(name);
-	if (iterToVector != m_callbacks.end())
-	{
-		std::vector<std::pair<setting_changed_callback, void*> >::iterator iter;
-		for (iter = iterToVector->second.begin(); iter != iterToVector->second.end(); ++iter)
-		{
-			(iter->first)(name, iter->second);
-		}
+	MutexAutoLock lock(m_callback_mutex);
+
+	SettingsCallbackMap::const_iterator it_cbks = m_callbacks.find(name);
+	if (it_cbks != m_callbacks.end()) {
+		SettingsCallbackList::const_iterator it;
+		for (it = it_cbks->second.begin(); it != it_cbks->second.end(); ++it)
+			(it->first)(name, it->second);
 	}
 }
diff --git a/src/settings.h b/src/settings.h
index 80d41fd7..0af861a5 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -35,8 +35,17 @@ struct NoiseParams;
 extern Settings *g_settings;
 extern std::string g_settings_path;
 
-/** function type to register a changed callback */
-typedef void (*setting_changed_callback)(const std::string &name, void *data);
+// Type for a settings changed callback function
+typedef void (*SettingsChangedCallback)(const std::string &name, void *data);
+
+typedef std::vector<
+	std::pair<
+		SettingsChangedCallback,
+		void *
+	>
+> SettingsCallbackList;
+
+typedef std::map<std::string, SettingsCallbackList> SettingsCallbackMap;
 
 enum ValueType {
 	VALUETYPE_STRING,
@@ -209,24 +218,28 @@ public:
 	void clearDefaults();
 	void updateValue(const Settings &other, const std::string &name);
 	void update(const Settings &other);
-	void registerChangedCallback(std::string name, setting_changed_callback cbf, void *userdata = NULL);
-	void deregisterChangedCallback(std::string name, setting_changed_callback cbf, void *userdata = NULL);
+
+	void registerChangedCallback(const std::string &name,
+		SettingsChangedCallback cbf, void *userdata = NULL);
+	void deregisterChangedCallback(const std::string &name,
+		SettingsChangedCallback cbf, void *userdata = NULL);
 
 private:
-
 	void updateNoLock(const Settings &other);
 	void clearNoLock();
 	void clearDefaultsNoLock();
 
-	void doCallbacks(std::string name);
+	void doCallbacks(const std::string &name) const;
 
 	std::map<std::string, SettingsEntry> m_settings;
 	std::map<std::string, SettingsEntry> m_defaults;
 
-	std::map<std::string, std::vector<std::pair<setting_changed_callback,void*> > > m_callbacks;
+	SettingsCallbackMap m_callbacks;
 
-	mutable Mutex m_callbackMutex;
-	mutable Mutex m_mutex; // All methods that access m_settings/m_defaults directly should lock this.
+	mutable Mutex m_callback_mutex;
+
+	// All methods that access m_settings/m_defaults directly should lock this.
+	mutable Mutex m_mutex;
 
 };