diff --git a/src/lib.rs b/src/lib.rs
index 0ded696..e5e6c09 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,6 +3,7 @@
 #[cfg(target_arch = "x86_64")]
 mod win64 {
 
+    #[cfg(target_os = "windows")]
     #[used] #[no_mangle]
     static _fltused: i32 = 0;