diff --git a/include/dwarfs/types.h b/include/dwarfs/types.h
index 4c8c57f0..0914000f 100644
--- a/include/dwarfs/types.h
+++ b/include/dwarfs/types.h
@@ -30,9 +30,11 @@ namespace dwarfs {
 using file_off_t = int64_t;
 
 #ifdef _WIN32
+#define SYS_MAIN wmain
 using sys_char = wchar_t;
 using sys_string = std::wstring;
 #else
+#define SYS_MAIN main
 using sys_char = char;
 using sys_string = std::string;
 #endif
diff --git a/include/dwarfs_tool_main.h b/include/dwarfs_tool_main.h
index a79e6bb0..4e103673 100644
--- a/include/dwarfs_tool_main.h
+++ b/include/dwarfs_tool_main.h
@@ -28,12 +28,6 @@
 
 #include "dwarfs/types.h"
 
-#ifdef _WIN32
-#define SYS_MAIN wmain
-#else
-#define SYS_MAIN main
-#endif
-
 namespace dwarfs {
 
 struct iolayer;