diff --git a/usr.bin/sort/sort.h b/usr.bin/sort/sort.h
index f6505c9b2a99..0a90637bd4f7 100644
--- a/usr.bin/sort/sort.h
+++ b/usr.bin/sort/sort.h
@@ -41,7 +41,7 @@
 
 #define	VERSION	"2.3-FreeBSD"
 
-#define	UNUSED_ARG(A) do { A=A; } while(0)
+#define	UNUSED_ARG(A) do { (void)(A); } while(0)
 
 #ifdef WITHOUT_NLS
 #define	getstr(n)	 nlsstr[n]