diff -ruNa a/include/ixion/env.hpp b/include/ixion/env.hpp
--- a/include/ixion/env.hpp	2022-11-01 03:01:01.000000000 +0100
+++ b/include/ixion/env.hpp	2024-09-19 22:07:12.251733220 +0200
@@ -36,7 +36,7 @@
   #define IXION_DLLPUBLIC_VAR IXION_DLLPUBLIC extern
 #endif
 
-#if _WIN32
+#if defined _WIN32
 #define IXION_MOD_EXPORT __declspec(dllexport)
 #else
 #define IXION_MOD_EXPORT __attribute__ ((visibility ("default")))