diff --git a/internal/core/src/index/thirdparty/faiss/FaissHook.h b/internal/core/src/index/thirdparty/faiss/FaissHook.h
index 381e03539b..4f1513e99b 100644
--- a/internal/core/src/index/thirdparty/faiss/FaissHook.h
+++ b/internal/core/src/index/thirdparty/faiss/FaissHook.h
@@ -31,10 +31,10 @@ extern sq_get_distance_computer_func_ptr sq_get_distance_computer;
 extern sq_sel_quantizer_func_ptr sq_sel_quantizer;
 extern sq_sel_inv_list_scanner_func_ptr sq_sel_inv_list_scanner;
 
-extern bool support_avx512();
-extern bool support_avx2();
-extern bool support_sse4_2();
+bool support_avx512();
+bool support_avx2();
+bool support_sse4_2();
 
-extern bool hook_init(std::string& cpu_flag);
+bool hook_init(std::string& cpu_flag);
 
 } // namespace faiss