the default pool thread number is thread hw concurrency

source/gui/widgets/skeletons/text_editor.cpp

@@ -2086,7 +2086,7 @@ namespace nana{	namespace widgets
 
 		void text_editor::copy() const
 		{
-			//Stops copying text if the text_editor is masked.
+			//Disallows copying text if the text_editor is masked.
 			if (mask_char_)
 				return;
 

source/threads/pool.cpp

@@ -351,10 +351,17 @@ namespace threads
 			}container_;
 		};//end class impl
 
-		pool::pool()
-			: impl_(new impl(4))
+#ifndef STD_THREAD_NOT_SUPPORTED
+		pool::pool(unsigned thread_number)
+			: impl_(new impl(thread_number ? thread_number : std::thread::hardware_concurrency()))
 		{
 		}
+#else
+		pool::pool(unsigned thread_number)
+			: impl_(new impl(0))
+		{
+		}
+#endif
 
 		pool::pool(pool&& other)
 			: pool()
@@ -362,11 +369,6 @@ namespace threads
 			std::swap(impl_, other.impl_);
 		}
 
-		pool::pool(std::size_t thread_number)
-			: impl_(new impl(thread_number))
-		{
-		}
-
 		pool& pool::operator=(pool&& other)
 		{
 			if(this != &other)