diff --git a/test/iterator_traits_test.cpp b/test/iterator_traits_test.cpp
index cbfedd7..6cdb2c6 100644
--- a/test/iterator_traits_test.cpp
+++ b/test/iterator_traits_test.cpp
@@ -155,10 +155,11 @@ input_iterator_test<std::istream_iterator<int>, int, std::ptrdiff_t, int*, int&,
 
 // C++20 changed ostream_iterator::difference_type to ptrdiff_t.
 // Note: gcc 10.1 defines __cplusplus to a value less than 202002L, but greater than 201703L in C++20 mode.
-#if __cplusplus > 201703L && (\
-    (defined(BOOST_LIBSTDCXX_VERSION) && BOOST_LIBSTDCXX_VERSION >= 100100) \
-    ) || \
-    defined(_MSVC_LANG) && _MSVC_LANG > 201703L && _MSVC_STL_UPDATE >= 202010L
+#if (__cplusplus > 201703L && ( \
+        (defined(BOOST_LIBSTDCXX_VERSION) && BOOST_LIBSTDCXX_VERSION >= 100100) || \
+        (defined(_LIBCPP_VERSION) && _LIBCPP_VERSION >= 12000)
+    )) || \
+    (defined(_MSVC_LANG) && _MSVC_LANG > 201703L && _MSVC_STL_UPDATE >= 202010L)
 #define BOOST_ITERATOR_CXX20_OSTREAM_ITERATOR
 #endif