diff --git a/src/format.hpp b/src/format.hpp
index fe8565b..cbece27 100644
--- a/src/format.hpp
+++ b/src/format.hpp
@@ -21,7 +21,7 @@
 template <>
 struct GetFormatType<bool>
 {
-    static constexpr auto format = "%d";
+    static constexpr auto format = "=%d";
 };
 template <>
 struct GetFormatType<char>