Update user defined type example

README.md

@@ -269,21 +269,24 @@ void multi_sink_example2()
 ---
 #### User defined types
 ```c++
-// user defined types logging by implementing operator<<
+#ifdef SPDLOG_USE_STD_FORMAT
-#include "spdlog/fmt/ostr.h" // must be included
+namespace std {
-struct my_type
+#else
+namespace fmt {
+#endif
+template<>
+struct formatter<my_type> : formatter<std::string>
 {
-    int i;
+    auto format(my_type my, format_context &ctx) -> decltype(ctx.out())
-    template<typename OStream>
-    friend OStream &operator<<(OStream &os, const my_type &c)
     {
-        return os << "[my_type i=" << c.i << "]";
+        return format_to(ctx.out(), "[my_type i={}]", my.i);
     }
 };
+}
 
 void user_defined_example()
 {
-    spdlog::get("console")->info("user defined type: {}", my_type{14});
+    spdlog::info("user defined type: {}", my_type(14));
 }
 
 ```

example/example.cpp

@@ -262,22 +262,26 @@ struct my_type
         : i(i){};
 };
 
-// Using a namespace alias like fmt_lib is not allowed when extending an existing namespace,
+#ifndef SPDLOG_USE_STD_FORMAT // when using fmtlib
-// but the correct namespace can still be selected with the SPDLOG_USE_STD_FORMAT macro.
-#ifdef SPDLOG_USE_STD_FORMAT
-namespace std {
-#else
-namespace fmt {
-#endif
 template<>
-struct formatter<my_type> : formatter<std::string>
+struct fmt::formatter<my_type> : fmt::formatter<std::string>
 {
     auto format(my_type my, format_context &ctx) -> decltype(ctx.out())
     {
         return format_to(ctx.out(), "[my_type i={}]", my.i);
     }
 };
+
+#else // when using std::format
+template<>
+struct std::formatter<my_type> : std::formatter<std::string>
+{
+    auto format(my_type my, format_context &ctx) -> decltype(ctx.out())
+    {
+        return format_to(ctx.out(), "[my_type i={}]", my.i);
     }
+};
+#endif
 
 void user_defined_example()
 {