diff --git a/glib/gstrfuncs.h b/glib/gstrfuncs.h
index 838ceb9fe8f10580a781c846caf21b18680554b0..7848a41b6677cef1f8082b255b9f695d040991cd 100644
--- a/glib/gstrfuncs.h
+++ b/glib/gstrfuncs.h
@@ -154,7 +154,7 @@ gboolean             (g_str_has_prefix) (const gchar *str,
  * Without it, it thinks strlen and memcmp may be getting passed NULL
  * despite the explicit check for NULL right above the calls.
  */
-#define _G_STR_NONNULL(x) ((x) + !(x))
+#define _G_STR_NONNULL(x) ((x) + (x == NULL))
 
 #define g_str_has_prefix(STR, PREFIX)                                         \
   (__builtin_constant_p (PREFIX)?                                             \