diff --git a/cmake/scripts/SquirrelExport.cmake b/cmake/scripts/SquirrelExport.cmake
--- a/cmake/scripts/SquirrelExport.cmake
+++ b/cmake/scripts/SquirrelExport.cmake
@@ -28,10 +28,10 @@ endmacro()
 macro(dump_class_templates NAME)
     string(REGEX REPLACE "^Script" "" REALNAME ${NAME})
 
-    string(APPEND SQUIRREL_EXPORT "\n	template <> inline ${NAME} *GetParam(ForceType<${NAME} *>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQUserPointer instance; sq_getinstanceup(vm, index, &instance, 0); return  (${NAME} *)instance; }")
-    string(APPEND SQUIRREL_EXPORT "\n	template <> inline ${NAME} &GetParam(ForceType<${NAME} &>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQUserPointer instance; sq_getinstanceup(vm, index, &instance, 0); return *(${NAME} *)instance; }")
-    string(APPEND SQUIRREL_EXPORT "\n	template <> inline const ${NAME} *GetParam(ForceType<const ${NAME} *>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQUserPointer instance; sq_getinstanceup(vm, index, &instance, 0); return  (${NAME} *)instance; }")
-    string(APPEND SQUIRREL_EXPORT "\n	template <> inline const ${NAME} &GetParam(ForceType<const ${NAME} &>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQUserPointer instance; sq_getinstanceup(vm, index, &instance, 0); return *(${NAME} *)instance; }")
+    string(APPEND SQUIRREL_EXPORT "\n	template <> inline ${NAME} *GetParam(ForceType<${NAME} *>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQUserPointer instance; sq_getinstanceup(vm, index, &instance, nullptr); return  (${NAME} *)instance; }")
+    string(APPEND SQUIRREL_EXPORT "\n	template <> inline ${NAME} &GetParam(ForceType<${NAME} &>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQUserPointer instance; sq_getinstanceup(vm, index, &instance, nullptr); return *(${NAME} *)instance; }")
+    string(APPEND SQUIRREL_EXPORT "\n	template <> inline const ${NAME} *GetParam(ForceType<const ${NAME} *>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQUserPointer instance; sq_getinstanceup(vm, index, &instance, nullptr); return  (${NAME} *)instance; }")
+    string(APPEND SQUIRREL_EXPORT "\n	template <> inline const ${NAME} &GetParam(ForceType<const ${NAME} &>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQUserPointer instance; sq_getinstanceup(vm, index, &instance, nullptr); return *(${NAME} *)instance; }")
     if("${NAME}" STREQUAL "ScriptEvent")
         string(APPEND SQUIRREL_EXPORT "\n	template <> inline int Return<${NAME} *>(HSQUIRRELVM vm, ${NAME} *res) { if (res == nullptr) { sq_pushnull(vm); return 1; } Squirrel::CreateClassInstanceVM(vm, \"${REALNAME}\", res, nullptr, DefSQDestructorCallback<${NAME}>, true); return 1; }")
     elseif("${NAME}" STREQUAL "ScriptText")
diff --git a/src/ai/ai_info.cpp b/src/ai/ai_info.cpp
--- a/src/ai/ai_info.cpp
+++ b/src/ai/ai_info.cpp
@@ -63,7 +63,7 @@ template <> const char *GetClassName<AII
 {
 	/* Get the AIInfo */
 	SQUserPointer instance = nullptr;
-	if (SQ_FAILED(sq_getinstanceup(vm, 2, &instance, 0)) || instance == nullptr) return sq_throwerror(vm, "Pass an instance of a child class of AIInfo to RegisterAI");
+	if (SQ_FAILED(sq_getinstanceup(vm, 2, &instance, nullptr)) || instance == nullptr) return sq_throwerror(vm, "Pass an instance of a child class of AIInfo to RegisterAI");
 	AIInfo *info = (AIInfo *)instance;
 
 	SQInteger res = ScriptInfo::Constructor(vm, info);
@@ -107,7 +107,7 @@ template <> const char *GetClassName<AII
 {
 	/* Get the AIInfo */
 	SQUserPointer instance;
-	sq_getinstanceup(vm, 2, &instance, 0);
+	sq_getinstanceup(vm, 2, &instance, nullptr);
 	AIInfo *info = (AIInfo *)instance;
 	info->api_version = nullptr;
 
diff --git a/src/game/game_info.cpp b/src/game/game_info.cpp
--- a/src/game/game_info.cpp
+++ b/src/game/game_info.cpp
@@ -54,7 +54,7 @@ template <> const char *GetClassName<Gam
 {
 	/* Get the GameInfo */
 	SQUserPointer instance = nullptr;
-	if (SQ_FAILED(sq_getinstanceup(vm, 2, &instance, 0)) || instance == nullptr) return sq_throwerror(vm, "Pass an instance of a child class of GameInfo to RegisterGame");
+	if (SQ_FAILED(sq_getinstanceup(vm, 2, &instance, nullptr)) || instance == nullptr) return sq_throwerror(vm, "Pass an instance of a child class of GameInfo to RegisterGame");
 	GameInfo *info = (GameInfo *)instance;
 
 	SQInteger res = ScriptInfo::Constructor(vm, info);
diff --git a/src/script/api/script_text.cpp b/src/script/api/script_text.cpp
--- a/src/script/api/script_text.cpp
+++ b/src/script/api/script_text.cpp
@@ -109,7 +109,7 @@ SQInteger ScriptText::_SetParam(int para
 			sq_pop(vm, 3);
 
 			/* Get the 'real' instance of this class */
-			sq_getinstanceup(vm, -1, &real_instance, 0);
+			sq_getinstanceup(vm, -1, &real_instance, nullptr);
 			if (real_instance == nullptr) return SQ_ERROR;
 
 			ScriptText *value = static_cast<ScriptText *>(real_instance);
diff --git a/src/script/squirrel.cpp b/src/script/squirrel.cpp
--- a/src/script/squirrel.cpp
+++ b/src/script/squirrel.cpp
@@ -256,7 +256,7 @@ void Squirrel::RunError(HSQUIRRELVM vm, 
 
 SQInteger Squirrel::_RunError(HSQUIRRELVM vm)
 {
-	const SQChar *sErr = 0;
+	const SQChar *sErr = nullptr;
 
 	if (sq_gettop(vm) >= 1) {
 		if (SQ_SUCCEEDED(sq_getstring(vm, -1, &sErr))) {
diff --git a/src/script/squirrel.hpp b/src/script/squirrel.hpp
--- a/src/script/squirrel.hpp
+++ b/src/script/squirrel.hpp
@@ -190,7 +190,7 @@ public:
 	 * @note This will only work just after a function-call from within Squirrel
 	 *  to your C++ function.
 	 */
-	static bool GetRealInstance(HSQUIRRELVM vm, SQUserPointer *ptr) { return SQ_SUCCEEDED(sq_getinstanceup(vm, 1, ptr, 0)); }
+	static bool GetRealInstance(HSQUIRRELVM vm, SQUserPointer *ptr) { return SQ_SUCCEEDED(sq_getinstanceup(vm, 1, ptr, nullptr)); }
 
 	/**
 	 * Get the Squirrel-instance pointer.
diff --git a/src/script/squirrel_helper.hpp b/src/script/squirrel_helper.hpp
--- a/src/script/squirrel_helper.hpp
+++ b/src/script/squirrel_helper.hpp
@@ -754,9 +754,9 @@ namespace SQConvert {
 		sq_pop(vm, 3);
 
 		/* Get the 'real' instance of this class */
-		sq_getinstanceup(vm, 1, &real_instance, 0);
+		sq_getinstanceup(vm, 1, &real_instance, nullptr);
 		/* Get the real function pointer */
-		sq_getuserdata(vm, nparam, &ptr, 0);
+		sq_getuserdata(vm, nparam, &ptr, nullptr);
 		if (real_instance == nullptr) return sq_throwerror(vm, "couldn't detect real instance of class for non-static call");
 		/* Remove the userdata from the stack */
 		sq_pop(vm, 1);
@@ -796,9 +796,9 @@ namespace SQConvert {
 		sq_pop(vm, 3);
 
 		/* Get the 'real' instance of this class */
-		sq_getinstanceup(vm, 1, &real_instance, 0);
+		sq_getinstanceup(vm, 1, &real_instance, nullptr);
 		/* Get the real function pointer */
-		sq_getuserdata(vm, nparam, &ptr, 0);
+		sq_getuserdata(vm, nparam, &ptr, nullptr);
 		if (real_instance == nullptr) return sq_throwerror(vm, "couldn't detect real instance of class for non-static call");
 		/* Remove the userdata from the stack */
 		sq_pop(vm, 1);
@@ -820,7 +820,7 @@ namespace SQConvert {
 		SQUserPointer ptr = nullptr;
 
 		/* Get the real function pointer */
-		sq_getuserdata(vm, nparam, &ptr, 0);
+		sq_getuserdata(vm, nparam, &ptr, nullptr);
 
 		try {
 			/* Delegate it to a template that can handle this specific function */
@@ -844,7 +844,7 @@ namespace SQConvert {
 		SQUserPointer ptr = nullptr;
 
 		/* Get the real function pointer */
-		sq_getuserdata(vm, nparam, &ptr, 0);
+		sq_getuserdata(vm, nparam, &ptr, nullptr);
 		/* Remove the userdata from the stack */
 		sq_pop(vm, 1);