diff --git a/publish.gradle b/publish.gradle
index c3782eb..7252ebe 100644
--- a/publish.gradle
+++ b/publish.gradle
@@ -128,7 +128,7 @@ if (file('repo_creds.properties').exists()) {
 publishing {
     repositories {
         maven {
-            if (project.version.contains('SNAPSHOT')) {
+            if (project.version.contains('dev')) {
                 url "http://nexus.rehlds.org/nexus/content/repositories/rehlds-snapshots/"
             } else {
                 url "http://nexus.rehlds.org/nexus/content/repositories/rehlds-releases/"
diff --git a/rehlds/rehlds/hookchains_impl.cpp b/rehlds/rehlds/hookchains_impl.cpp
index 998572a..07c61c2 100644
--- a/rehlds/rehlds/hookchains_impl.cpp
+++ b/rehlds/rehlds/hookchains_impl.cpp
@@ -27,12 +27,28 @@ AbstractHookChainRegistry::AbstractHookChainRegistry()
 	m_NumHooks = 0;
 }
 
-void AbstractHookChainRegistry::addHook(void* hookFunc, int priority) {
-	for (int i = 0; i < MAX_HOOKS_IN_CHAIN; i++)
-	{
+bool AbstractHookChainRegistry::findHook(void* hookFunc) const
+{
+	for (auto i = 0; i < m_NumHooks; i++) {
 		if (m_Hooks[i] == hookFunc)
-			return;
+			return true;
+	}
 
+	return false;
+}
+
+void AbstractHookChainRegistry::addHook(void* hookFunc, int priority)
+{
+	if (!hookFunc) {
+		Sys_Error(__FUNCTION__ " Parameter hookFunc can't be a nullptr");
+	}
+
+	if (findHook(hookFunc)) {
+		Sys_Error(__FUNCTION__ " The same handler can't be used twice on the hookchain.");
+	}
+
+	for (auto i = 0; i < MAX_HOOKS_IN_CHAIN; i++)
+	{
 		if (m_Hooks[i] && priority <= m_Priorities[i])
 			continue;
 
@@ -47,7 +63,7 @@ void AbstractHookChainRegistry::addHook(void* hookFunc, int priority) {
 	}
 
 	if (m_NumHooks >= MAX_HOOKS_IN_CHAIN) {
-		rehlds_syserror("MAX_HOOKS_IN_CHAIN limit hit");
+		Sys_Error(__FUNCTION__ " MAX_HOOKS_IN_CHAIN limit hit");
 	}
 
 	m_NumHooks++;
@@ -56,7 +72,7 @@ void AbstractHookChainRegistry::addHook(void* hookFunc, int priority) {
 void AbstractHookChainRegistry::removeHook(void* hookFunc) {
 
 	// erase hook
-	for (int i = 0; i < m_NumHooks; i++)
+	for (auto i = 0; i < m_NumHooks; i++)
 	{
 		if (hookFunc == m_Hooks[i])
 		{
diff --git a/rehlds/rehlds/hookchains_impl.h b/rehlds/rehlds/hookchains_impl.h
index 51de16a..3b46150 100644
--- a/rehlds/rehlds/hookchains_impl.h
+++ b/rehlds/rehlds/hookchains_impl.h
@@ -92,7 +92,8 @@ public:
 	}
 
 	virtual void callOriginal(t_args... args) {
-		m_OriginalFunc(args...);
+		if (m_OriginalFunc)
+			m_OriginalFunc(args...);
 	}
 
 private:
@@ -108,6 +109,7 @@ protected:
 
 protected:
 	void addHook(void* hookFunc, int priority);
+	bool findHook(void* hookFunc) const;
 	void removeHook(void* hookFunc);
 
 public: