diff --git a/sys/sys/_offsetof.h b/sys/sys/_offsetof.h
index 25982fad774a..7a38914818a0 100644
--- a/sys/sys/_offsetof.h
+++ b/sys/sys/_offsetof.h
@@ -1,19 +1,19 @@
 /*
  * Copyright (c) 2026 Capabilities Limited
  *
  * SPDX-License-Identifier: BSD-2-Clause
  *
  * This software was developed by SRI International, the University of
  * Cambridge Computer Laboratory (Department of Computer Science and
  * Technology), and Capabilities Limited under Defense Advanced Research
  * Projects Agency / Air Force Research Laboratory (DARPA/AFRL) Contract
  * No. FA8750-24-C-B047 ("DEC").
  */
 #ifndef _SYS__OFFSETOF_H_
 #define	_SYS__OFFSETOF_H_
 
 #ifndef offsetof
-#define offsetof(type, field)   __builtin_offsetof(type, field)
+#define offsetof(TYPE, MEMBER) __builtin_offsetof (TYPE, MEMBER)
 #endif
 
 #endif /* _SYS__OFFSETOF_H_ */