diff --git a/src/colour.cpp b/src/colour.cpp
index 5b23601..48dc07c 100644
--- a/src/colour.cpp
+++ b/src/colour.cpp
@@ -1,4 +1,5 @@
 #include <string>
+#include <cstdio>
 #include <cstdlib>
 #include "colour.h"