diff --git a/src/backdrop.h b/src/backdrop.h
index e018907..e85902b 100644
--- a/src/backdrop.h
+++ b/src/backdrop.h
@@ -2,6 +2,6 @@
 #define BACKDROP_H
 
 extern int colour;
-int backdrop (int colour);
+int backdrop(int colour);
 
 #endif