diff --git a/runtime/Cpp/runtime/CMakeLists.txt b/runtime/Cpp/runtime/CMakeLists.txt
index 19cc21c..2a33fe9 100644
--- a/runtime/Cpp/runtime/CMakeLists.txt
+++ b/runtime/Cpp/runtime/CMakeLists.txt
@@ -103,7 +103,7 @@ set(static_lib_suffix "")
 if (WIN32)
   set(static_lib_suffix "-static")
   if(BUILD_SHARED_LIBS)
-  target_compile_definitions(antlr4_shared PUBLIC ANTLR4CPP_EXPORTS)
+  target_compile_definitions(antlr4_shared PRIVATE ANTLR4CPP_EXPORTS)
   else()
   target_compile_definitions(antlr4_static PUBLIC ANTLR4CPP_STATIC)
   endif()