diff --git a/luna/src/Format.cpp b/luna/src/Format.cpp
index c06a51a9..adb90550 100644
--- a/luna/src/Format.cpp
+++ b/luna/src/Format.cpp
@@ -241,7 +241,7 @@ static usize to_string(usize value, usize base, char* buf, usize max, bool upper
     return i;
 }
 
-static Result<void> output_integer_data(conv_state& vstate, format_state& state, char* buf, usize len)
+static Result<void> output_integer_data(const conv_state& vstate, format_state& state, char* buf, usize len)
 {
     if (!(vstate.flags & FLAG_ZERO_PAD)) TRY(start_pad(vstate, state, len));
 
@@ -254,7 +254,7 @@ static Result<void> output_integer_data(conv_state& vstate, format_state& state,
     return {};
 }
 
-static void output_pure_integer_data(conv_state& vstate, pure_format_state& state, char* buf, usize len)
+static void output_pure_integer_data(const conv_state& vstate, pure_format_state& state, char* buf, usize len)
 {
     if (!(vstate.flags & FLAG_ZERO_PAD)) pure_start_pad(vstate, state, len);
 
@@ -268,7 +268,7 @@ static void output_pure_integer_data(conv_state& vstate, pure_format_state& stat
 template <typename ReturnType, typename FormatStateType>
 static ReturnType output_integer_generic(char specifier, conv_state& vstate, FormatStateType& state, usize value,
                                          bool negative,
-                                         ReturnType (*output_data)(conv_state&, FormatStateType&, char*, usize))
+                                         ReturnType (*output_data)(const conv_state&, FormatStateType&, char*, usize))
 {
     usize base = 10;
     bool uppercase = false;