diff --git a/include/wrenpp/vm.hpp b/include/wrenpp/vm.hpp
index 39e0acc..d649aa8 100644
--- a/include/wrenpp/vm.hpp
+++ b/include/wrenpp/vm.hpp
@@ -54,8 +54,8 @@ namespace wren {
 			void* (*reallocate_fn)(void*, std::size_t) {nullptr};
 			const char* (*resolve_module_fn)(Configuration&, VM*, const char*, const char*) {nullptr};
 			char* (*load_module_fn)(Configuration&, VM*, const char*) {nullptr};
-			foreign_method_t (*foreign_method_fn)(Configuration&, VM*, const char*, const char*, bool, const char*);
-			foreign_class_t (*foreign_class_fn)(Configuration&, VM*, const char*, const char*);
+			foreign_method_t (*foreign_method_fn)(Configuration&, VM*, const char*, const char*, bool, const char*) {nullptr};
+			foreign_class_t (*foreign_class_fn)(Configuration&, VM*, const char*, const char*) {nullptr};
 
 			Configuration* config_obj {nullptr};
 			VM* owner {nullptr};