vs2013 support

include/c11log/sinks/stdout_sinks.h

@@ -1,32 +1,40 @@
 #pragma once
 
 #include <iostream>
+#include <mutex>
+#include <memory>
+
 #include "base_sink.h"
 
 namespace c11log {
 namespace sinks {
 class ostream_sink: public base_sink {
 public:
-    ostream_sink(std::ostream& os):_ostream(os) {}
+    explicit ostream_sink(std::ostream& os):_ostream(os) {}
+	ostream_sink(const ostream_sink&) = delete;
+	ostream_sink& operator=(const ostream_sink&) = delete;
     virtual ~ostream_sink() = default;
 
 protected:
     virtual void _sink_it(const std::string& msg) override {
+		std::lock_guard<std::mutex> lock(_mutex);
         _ostream << msg;
     }
 
     std::ostream& _ostream;
+	std::mutex _mutex;
 };
 
-class stdout_sink:public ostream_sink {
-public:
-    stdout_sink():ostream_sink(std::cout) {}
-};
-
-class stderr_sink:public ostream_sink {
-public:
-    stderr_sink():ostream_sink(std::cerr) {}
-
-};
+inline std::shared_ptr<ostream_sink> cout_sink() {
+	static const ostream_sink& instance{std::cout};
+	return std::shared_ptr<ostream_sink>(&instance, [=](ostream_sink*) {});
+}
+
+inline std::shared_ptr<ostream_sink> cerr_sink() {
+	static const ostream_sink& instance = ostream_sink(std::cerr);
+	return std::shared_ptr<ostream_sink>(&instance, [=](ostream_sink*) {});
+}
+
+
+}
 }
-}