Fix Visual Studio poor std::this_thread::get_id() performance by using...

Fix Visual Studio poor  std::this_thread::get_id() performance by using GetCurrentThreadId() (and pthread_self() under linux)

include/spdlog/details/async_log_helper.h

@@ -60,7 +60,7 @@ class async_log_helper
         level::level_enum level;
         log_clock::time_point time;
         std::string txt;
-        std::thread::id thread_id;
+        uint64_t thread_id;
 
         async_msg() = default;
         ~async_msg() = default;

include/spdlog/details/line_logger.h

@@ -64,7 +64,9 @@ public:
         {
             _log_msg.logger_name = _callback_logger->name();
             _log_msg.time = os::now();
-            _log_msg.thread_id = std::this_thread::get_id();
+            _log_msg.thread_id = os::thread_id();
+
+
             _callback_logger->_log_msg(_log_msg);
         }
     }

include/spdlog/details/log_msg.h

@@ -46,7 +46,7 @@ struct log_msg
 
     log_msg(const log_msg& other) :
         logger_name(other.logger_name),
-        level(other.level),        
+        level(other.level),
         time(other.time),
         thread_id(other.thread_id)
     {
@@ -84,7 +84,7 @@ struct log_msg
 
     void clear()
     {
-        level = level::off;        
+        level = level::off;
         raw.clear();
         formatted.clear();
     }
@@ -92,7 +92,7 @@ struct log_msg
     std::string logger_name;
     level::level_enum level;
     log_clock::time_point time;
-    std::thread::id thread_id;
+    uint64_t thread_id;
     fmt::MemoryWriter raw;
     fmt::MemoryWriter formatted;
 };

include/spdlog/details/os.h

@@ -32,6 +32,8 @@
 #  define WIN32_LEAN_AND_MEAN
 # endif
 # include <Windows.h>
+#else
+#include <pthread.h>
 #endif
 
 #include "../common.h"
@@ -167,6 +169,17 @@ inline int utc_minutes_offset(const std::tm& tm = details::os::localtime())
 }
 
 
+inline uint64_t thread_id()
+{
+
+#ifdef _WIN32
+    return ::GetCurrentThreadId();
+#else
+    return (uint64_t) pthread_self();
+#endif
+
+}
+
 } //os
 } //details
 } //spdlog

include/spdlog/details/pattern_formatter_impl.h

@@ -354,7 +354,7 @@ class t_formatter :public flag_formatter
 {
     void format(details::log_msg& msg, const std::tm&) override
     {
-        msg.formatted << std::hash<std::thread::id>()(msg.thread_id);
+        msg.formatted << msg.thread_id;
     }
 };
 
@@ -478,7 +478,7 @@ inline void spdlog::pattern_formatter::handle_flag(char flag)
 {
     switch (flag)
     {
-        // logger name
+    // logger name
     case 'n':
         _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::name_formatter()));
         break;