diff --git a/MiniScript-cpp/src/DateTimeUtils.cpp b/MiniScript-cpp/src/DateTimeUtils.cpp
index 9c6a94b..8cf5984 100644
--- a/MiniScript-cpp/src/DateTimeUtils.cpp
+++ b/MiniScript-cpp/src/DateTimeUtils.cpp
@@ -34,7 +34,7 @@ static bool Match(const String s, size_t *posB, const String match) {
 String FormatDate(time_t t, String formatSpec) {
 	tm dateTime;
 	struct tm *newtime = localtime_r(&t, &dateTime);
-	if (errno or newtime == nullptr) return "";  // arg t too large
+	if (newtime == nullptr) return "";  // arg t too large
 	
 	const int BUFSIZE = 128;
 	char buffer[BUFSIZE];
diff --git a/MiniScript-cpp/tests/testDateTimeDateStr.ms b/MiniScript-cpp/tests/testDateTimeDateStr.ms
index 69d3176..b2ff00a 100644
--- a/MiniScript-cpp/tests/testDateTimeDateStr.ms
+++ b/MiniScript-cpp/tests/testDateTimeDateStr.ms
@@ -1,6 +1,7 @@
 import "qa"
 
 testDateTimeDateStr = function
+	qa.assertEqual _dateStr(0), "2000-01-01 00:00:00"
 	qa.assertEqual _dateStr(1e20), ""
 end function