diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index f5fe085eb..dadd8a30c 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -3731,7 +3731,7 @@
  * If the implementation here is empty, this will effectively disable the
  * checking of functions' return values.
  */
-//#define MBEDTLS_CHECK_RETURN __attribute__(__warn_unused_result__)
+//#define MBEDTLS_CHECK_RETURN __attribute__((__warn_unused_result__))
 
 /* PSA options */
 /**