diff --git a/tests/test_find.cpp b/tests/test_find.cpp
index 7559072..385b65b 100644
--- a/tests/test_find.cpp
+++ b/tests/test_find.cpp
@@ -965,9 +965,7 @@ TEST_CASE("testing toml::find offset_datetime")
         const auto timet = std::chrono::system_clock::to_time_t(date);
 
         // get time_t as gmtime (2018-04-01T03:30:00Z)
-        const auto tmp = std::gmtime(std::addressof(timet)); // XXX not threadsafe!
-        CHECK_UNARY(tmp);
-        const auto tm = *tmp;
+        const auto tm = toml::detail::gmtime_s(std::addressof(timet));
         CHECK_EQ(tm.tm_year + 1900,  2018);
         CHECK_EQ(tm.tm_mon  + 1,        4);
         CHECK_EQ(tm.tm_mday,            1);