diff --git a/src/header/bits_null/cbindgen.toml b/src/header/bits_null/cbindgen.toml
index be6b69c17f..f0f1e8a10e 100644
--- a/src/header/bits_null/cbindgen.toml
+++ b/src/header/bits_null/cbindgen.toml
@@ -11,7 +11,11 @@ language = "C"
 no_includes = true
 after_includes = """
 #ifdef __cplusplus
+#if __cplusplus >= 201103L
   #define NULL nullptr
+#else
+  #define NULL 0L
+#endif
 #else
   #define NULL ((void *)0)
 #endif