ログクラスを作る その3

スレッドセーフにする

main.cpp

#include "log.h"
#include <thread>


int main() {
	const std::wstring path = L".\\";
	const std::wstring name = L"test.txt";

	static Log &log = Log::GetInstance(path, name);

	std::thread t1([&](){ for (int i=0;i<10;i++) log.OutFile(L"Hello thread1!"); });
	std::thread t2([&](){ for (int i=0;i<10;i++) log.OutFile(L"Hello thread2!"); });
	std::thread t3([&](){ for (int i=0;i<10;i++) log.OutFile(L"Hello thread3!"); });

	t1.join();
	t2.join();
	t3.join();

	return 0;
}

Log.h

#include <string>
#include <mutex>

class Log
{
public:
	static Log &GetInstance(
		const std::wstring path,
		const std::wstring filename
	);

	void OutFile(
		const std::wstring msg
	);

private: // コンストラクタデストラクタコピーコンストラクタ代入はプライベートで定義
	Log(
		const std::wstring path,
		const std::wstring filename
	);
	~Log() {};
	Log(const Log &other) {};
	Log& operator=(const Log &other) {};

private:
	std::recursive_mutex m_mtx;
	std::wstring m_file_location;

};

Log.cpp

#include "Log.h"
#include <fstream>

Log &Log::GetInstance(
	const std::wstring path,
	const std::wstring name
) {
	static Log instance(path, name);  // 一度だけLogインスタンスを生成する
	return instance;
}

Log::Log(
	const std::wstring path,
	const std::wstring name
) {
	m_file_location = path;
	m_file_location += name;
}

void Log::OutFile(
	const std::wstring msg
) {
	std::unique_lock<std::recursive_mutex> lock(m_mtx);
	std::wofstream wfs; // wstring用filestreamの型
	wfs.open(m_file_location, std::ios::app);
	wfs << msg << std::endl;
}