diff --git a/src_main/core/piinit.cpp b/src_main/core/piinit.cpp
index 3f26f314..6063a2c5 100644
--- a/src_main/core/piinit.cpp
+++ b/src_main/core/piinit.cpp
@@ -265,15 +265,15 @@ PIInit::PIInit() {
 	sinfo->OS_name =
 #ifdef WINDOWS
 			PIStringAscii("Windows");
-#elif QNX
+#elif defined(QNX)
 			PIStringAscii("QNX");
-#elif MAC_OS
+#elif defined(MAC_OS)
 			PIStringAscii("MacOS");
-#elif ANDROID
+#elif defined(ANDROID)
 			PIStringAscii("Android");
-#elif FREE_BSD
+#elif defined(FREE_BSD)
 			PIStringAscii("FreeBSD");
-#elif FREERTOS
+#elif defined(FREERTOS)
 			PIStringAscii("FreeRTOS");
 #else
 			uns.sysname;