diff --git a/src/libCom/test/cvtFastTest.c b/src/libCom/test/cvtFastTest.c
index 5d2c8af20..7943f5baf 100644
--- a/src/libCom/test/cvtFastTest.c
+++ b/src/libCom/test/cvtFastTest.c
@@ -46,8 +46,11 @@ MAIN(cvtFastTest)
     epicsFloat32 val_Float;
     epicsFloat64 val_Double;
 
-#if defined(WIN32) && (!defined(_MINGW) || __MSVCRT_VERSION__ >= 0x0800)
+#ifdef _WIN32
+#if (defined(_MSC_VER) && _MSC_VER < 1900) || \
+    (defined(_MINGW) && defined(_TWO_DIGIT_EXPONENT))
     _set_output_format(_TWO_DIGIT_EXPONENT);
+#endif
 #endif
 
     testPlan(1062);