Use std::vformat

include/spdlog/logger.h

@@ -321,13 +321,14 @@ protected:
         assert(should_log(lvl));
         SPDLOG_TRY
         {
-            memory_buf_t buf;
 #ifdef SPDLOG_USE_STD_FORMAT
-            fmt_lib::vformat_to(std::back_inserter(buf), fmt, fmt_lib::make_format_args(args...));
-#else
-            fmt::vformat_to(fmt::appender(buf), fmt, fmt::make_format_args(args...));
-#endif
+            auto formatted = std::vformat(fmt, std::make_format_args(args...));
+            sink_it_(details::log_msg(loc, name_, lvl, formatted));
+#else // use {fmt} lib
+            memory_buf_t buf;
+            fmt::vformat_to(std::back_inserter(buf), fmt, fmt::make_format_args(args...));
             sink_it_(details::log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size())));
+#endif
         }
         SPDLOG_LOGGER_CATCH(loc)
     }