diff --git a/v2/test/railsys/libx/include/libx/test_libx.h b/v2/test/railsys/libx/include/libx/test_libx.h
index 15e3db978..285ff2d10 100644
--- a/v2/test/railsys/libx/include/libx/test_libx.h
+++ b/v2/test/railsys/libx/include/libx/test_libx.h
@@ -7,6 +7,13 @@
 // software is provided "as is" without express or implied warranty, and
 // with no claim as to its suitability for any purpose.
 
+#ifdef _WIN32
+#ifdef LIBX_SOURCE
+__declspec(dllexport)
+#else
+__declspec(dllimport)
+#endif
+#endif
 class TestLibX
 {
 public:
diff --git a/v2/test/railsys/libx/src/test_libx.cpp b/v2/test/railsys/libx/src/test_libx.cpp
index d006d442e..34458c86e 100644
--- a/v2/test/railsys/libx/src/test_libx.cpp
+++ b/v2/test/railsys/libx/src/test_libx.cpp
@@ -8,6 +8,7 @@
 // with no claim as to its suitability for any purpose.
 
 
+#define LIBX_SOURCE
 #include <libx/test_libx.h>
 
 TestLibX::TestLibX()