diff --git a/src/mod_loader.cpp b/src/mod_loader.cpp
index 6589827..b21d600 100644
--- a/src/mod_loader.cpp
+++ b/src/mod_loader.cpp
@@ -1,6 +1,6 @@
 #include "mod_loader.hpp"
 
-ModLoader::open_file_stream_proc oldOpenFileStream = nullptr;
+ModLoader::open_file_stream_proc ModLoader::oldOpenFileStream = nullptr;
 
 int ModLoader::pattern_size;
 unsigned char* ModLoader::pattern;
diff --git a/src/mod_loader.hpp b/src/mod_loader.hpp
index 3474404..264c294 100644
--- a/src/mod_loader.hpp
+++ b/src/mod_loader.hpp
@@ -12,11 +12,12 @@ class ModLoader {
     static bool Enable();
     static void Disable();
 
-    typedef bool(__fastcall* open_file_stream_proc)(__int64 stream, LPCSTR file_path, unsigned int flags);
-
 private:
+    using open_file_stream_proc = bool(__fastcall*)(uintptr_t stream, LPCSTR file_path, unsigned int flags);
+
     static bool __fastcall HookOpenFileStream(uintptr_t stream, LPCSTR file_path, unsigned int flags);
 
+    static open_file_stream_proc oldOpenFileStream;
     static int pattern_size;
     static unsigned char* pattern;
     static unsigned char* mask;