diff --git a/bemani/protocol/lz77.py b/bemani/protocol/lz77.py
index 0b7aef6..de82f25 100644
--- a/bemani/protocol/lz77.py
+++ b/bemani/protocol/lz77.py
@@ -13,6 +13,8 @@ try:
         clib = ctypes.cdll.LoadLibrary(os.path.join(clib_path, files[0]))
         clib.decompress.argtypes = (ctypes.c_char_p, ctypes.c_int, ctypes.c_char_p, ctypes.c_int)
         clib.decompress.restype = ctypes.c_int
+        clib.compress.argtypes = (ctypes.c_char_p, ctypes.c_int, ctypes.c_char_p, ctypes.c_int)
+        clib.compress.restype = ctypes.c_int
 except Exception:
     clib = None