diff --git a/include/spdlog/details/async_log_helper.h b/include/spdlog/details/async_log_helper.h
index 4b1395ca..eecf804a 100644
--- a/include/spdlog/details/async_log_helper.h
+++ b/include/spdlog/details/async_log_helper.h
@@ -125,9 +125,9 @@ private:
 
     // last exception thrown from the worker thread
     std::shared_ptr<spdlog_ex> _last_workerthread_ex;
-	
-	// worker thread warmup callback - one can set thread priority, affinity, etc
-	const std::function<void()> _worker_warmup_cb;
+
+    // worker thread warmup callback - one can set thread priority, affinity, etc
+    const std::function<void()> _worker_warmup_cb;
 
 
     // throw last worker thread exception or if worker thread is not active
@@ -154,7 +154,7 @@ inline spdlog::details::async_log_helper::async_log_helper(formatter_ptr formatt
     _formatter(formatter),
     _sinks(sinks),
     _q(queue_size),
-	_worker_warmup_cb(worker_warmup_cb),
+    _worker_warmup_cb(worker_warmup_cb),
     _worker_thread(&async_log_helper::worker_loop, this)
 {}
 
@@ -194,7 +194,7 @@ inline void spdlog::details::async_log_helper::worker_loop()
 {
     try
     {
-		if (_worker_warmup_cb) _worker_warmup_cb();
+        if (_worker_warmup_cb) _worker_warmup_cb();
         clock::time_point last_pop = clock::now();
         while(process_next_msg(last_pop));
     }
diff --git a/include/spdlog/details/async_logger_impl.h b/include/spdlog/details/async_logger_impl.h
index ec341578..455f11c2 100644
--- a/include/spdlog/details/async_logger_impl.h
+++ b/include/spdlog/details/async_logger_impl.h
@@ -44,7 +44,10 @@ inline spdlog::async_logger::async_logger(const std::string& logger_name, sinks_
     async_logger(logger_name, sinks.begin(), sinks.end(), queue_size, worker_warmup_cb) {}
 
 inline spdlog::async_logger::async_logger(const std::string& logger_name, sink_ptr single_sink, size_t queue_size, const std::function<void()>& worker_warmup_cb) :
-    async_logger(logger_name, { single_sink }, queue_size, worker_warmup_cb) {}
+    async_logger(logger_name,
+{
+    single_sink
+}, queue_size, worker_warmup_cb) {}
 
 
 inline void spdlog::async_logger::_set_formatter(spdlog::formatter_ptr msg_formatter)
diff --git a/include/spdlog/details/registry.h b/include/spdlog/details/registry.h
index a3911e97..9c25845f 100644
--- a/include/spdlog/details/registry.h
+++ b/include/spdlog/details/registry.h
@@ -125,7 +125,7 @@ public:
         std::lock_guard<std::mutex> lock(_mutex);
         _async_mode = true;
         _async_q_size = q_size;
-		_worker_warmup_cb = worker_warmup_cb;
+        _worker_warmup_cb = worker_warmup_cb;
     }
 
     void set_sync_mode()
@@ -151,7 +151,7 @@ private:
     level::level_enum _level = level::info;
     bool _async_mode = false;
     size_t _async_q_size = 0;
-	std::function<void()> _worker_warmup_cb = nullptr;
+    std::function<void()> _worker_warmup_cb = nullptr;
 };
 }
 }
diff --git a/include/spdlog/spdlog.h b/include/spdlog/spdlog.h
index 89153895..92894b85 100644
--- a/include/spdlog/spdlog.h
+++ b/include/spdlog/spdlog.h
@@ -63,7 +63,7 @@ void set_level(level::level_enum log_level);
 
 // Turn on async mode and set the queue size for each async_logger
 
-void set_async_mode(size_t queue_size, const std::function<void()>& worker_warmup_cb);
+void set_async_mode(size_t queue_size, const std::function<void()>& worker_warmup_cb = nullptr);
 // Turn off async mode
 void set_sync_mode();