diff --git a/toonz/sources/common/ttest/ttest.cpp b/toonz/sources/common/ttest/ttest.cpp
index 0fbd6f0a..568bf80a 100644
--- a/toonz/sources/common/ttest/ttest.cpp
+++ b/toonz/sources/common/ttest/ttest.cpp
@@ -15,7 +15,7 @@
 
 #include <set>
 
-#ifdef LINUX
+#if defined(LINUX)
 #include <typeinfo>
 #endif