Fix issue #769

include/spdlog/async.h

@@ -22,6 +22,7 @@
 #include "spdlog/details/thread_pool.h"
 
 #include <memory>
+#include <mutex>
 
 namespace spdlog {
 
@@ -38,13 +39,20 @@ struct async_factory_impl
     template<typename Sink, typename... SinkArgs>
     static std::shared_ptr<async_logger> create(const std::string &logger_name, SinkArgs &&... args)
     {
-        using details::registry;
-        auto sink = std::make_shared<Sink>(std::forward<SinkArgs>(args)...);
+        auto &registry_inst = details::registry::instance();
+
+		//create global thread pool if not already exists..
+        std::lock_guard<std::recursive_mutex>(registry_inst.tp_mutex());
+        auto tp = registry_inst.get_tp();
+        if (tp == nullptr)
+        {
+            tp = std::make_shared<details::thread_pool>(details::default_async_q_size, 1);
+            registry_inst.set_tp(tp);
+        }
 
-        // create default tp if not already exists.
-        auto tp = registry::instance().create_tp_once(details::default_async_q_size, 1);
+        auto sink = std::make_shared<Sink>(std::forward<SinkArgs>(args)...);
         auto new_logger = std::make_shared<async_logger>(logger_name, std::move(sink), std::move(tp), OverflowPolicy);
-        registry::instance().register_and_init(new_logger);
+        registry_inst.register_and_init(new_logger);
         return new_logger;
     }
 };

include/spdlog/details/registry.h

@@ -68,24 +68,14 @@ public:
 
     void set_tp(std::shared_ptr<thread_pool> tp)
     {
-        std::lock_guard<std::mutex> lock(tp_mutex_);
+        std::lock_guard<std::recursive_mutex> lock(tp_mutex_);
         tp_ = std::move(tp);
     }
 
-    // create tp only if not exists already
-    std::shared_ptr<thread_pool> create_tp_once(size_t queue_size, size_t n_threads)
-    {
-        std::lock_guard<std::mutex> lock(tp_mutex_);
-        if (tp_ == nullptr)
-        {
-            tp_ = std::make_shared<details::thread_pool>(queue_size, n_threads);
-        }
-        return tp_;
-    }
-
+ 
     std::shared_ptr<thread_pool> get_tp()
     {
-        std::lock_guard<std::mutex> lock(tp_mutex_);
+        std::lock_guard<std::recursive_mutex> lock(tp_mutex_);
         return tp_;
     }
 
@@ -178,16 +168,22 @@ public:
         drop_all();
 
         {
-            std::lock_guard<std::mutex> lock(tp_mutex_);
+            std::lock_guard<std::recursive_mutex> lock(tp_mutex_);
             tp_.reset();
         }
     }
 
+	std::recursive_mutex &tp_mutex()
+    {
+        return tp_mutex_;
+    }
+
     static registry &instance()
     {
         static registry s_instance;
         return s_instance;
     }
+	
 
 private:
     registry()
@@ -210,7 +206,7 @@ private:
     }
 
     std::mutex logger_map_mutex_, flusher_mutex_;
-    std::mutex tp_mutex_;
+    std::recursive_mutex tp_mutex_;    
     std::unordered_map<std::string, std::shared_ptr<logger>> loggers_;
     std::unique_ptr<formatter> formatter_;
     level::level_enum level_ = level::info;