diff --git a/include/fmt/format.h b/include/fmt/format.h
index db618a8e..5a410390 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -4093,7 +4093,7 @@ class udl_formatter {
 # else
 template <typename Char>
 struct udl_formatter {
-  const Char *str;
+  basic_string_view<Char> str;
 
   template <typename... Args>
   auto operator()(Args && ... args) const
@@ -4105,7 +4105,7 @@ struct udl_formatter {
 
 template <typename Char>
 struct udl_arg {
-  const Char *str;
+  basic_string_view<Char> str;
 
   template <typename T>
   named_arg<basic_context<Char>> operator=(T &&value) const {
@@ -4134,9 +4134,9 @@ constexpr internal::udl_formatter<Char, CHARS...> operator""_format() {
   \endrst
  */
 inline internal::udl_formatter<char>
-operator"" _format(const char *s, std::size_t) { return {s}; }
+operator"" _format(const char *s, std::size_t n) { return {s, n}; }
 inline internal::udl_formatter<wchar_t>
-operator"" _format(const wchar_t *s, std::size_t) { return {s}; }
+operator"" _format(const wchar_t *s, std::size_t n) { return {s, n}; }
 # endif // FMT_UDL_TEMPLATE
 
 /**
@@ -4150,9 +4150,9 @@ operator"" _format(const wchar_t *s, std::size_t) { return {s}; }
   \endrst
  */
 inline internal::udl_arg<char>
-operator"" _a(const char *s, std::size_t) { return {s}; }
+operator"" _a(const char *s, std::size_t n) { return {s, n}; }
 inline internal::udl_arg<wchar_t>
-operator"" _a(const wchar_t *s, std::size_t) { return {s}; }
+operator"" _a(const wchar_t *s, std::size_t n) { return {s, n}; }
 } // inline namespace literals
 } // namespace fmt
 #endif // FMT_USE_USER_DEFINED_LITERALS