diff --git a/include/str.h b/include/str.h
index d7aac249f6..44cd3a667d 100644
--- a/include/str.h
+++ b/include/str.h
@@ -32,7 +32,7 @@ extern "C" {
 /* Some compilers and/or C libraries do not handle printf("%s", NULL) correctly */
 #ifndef NUT_STRARG
 # if (defined REQUIRE_NUT_STRARG) && (REQUIRE_NUT_STRARG == 0)
-#  define NUT_STRARG(x) x
+#  define NUT_STRARG(x) (x)
 # else
 /* Is required, or not defined => err on safe side */
 #  define NUT_STRARG(x) (x?x:"(null)")