diff --git a/include/onnxruntime/core/session/onnxruntime_c_api.h b/include/onnxruntime/core/session/onnxruntime_c_api.h
index a35d975ac8..3d995e21e0 100644
--- a/include/onnxruntime/core/session/onnxruntime_c_api.h
+++ b/include/onnxruntime/core/session/onnxruntime_c_api.h
@@ -46,7 +46,7 @@ extern "C" {
 
 //! @}
 // SAL2 Definitions
-#ifndef _WIN32
+#ifndef _MSC_VER
 #define _In_
 #define _In_z_
 #define _In_opt_