如何在C++中实现一个简单的多线程文件管理器?

为了了解C++中的多线程编程,我正在实现一个基本的多线程记录器。

每次线程记录一条消息时;该消息被推到了deque的后面。

在一个单独的线程中,FileLogger检查deque中是否有任何消息,如果有,则将它们写入文件。

对deque的访问由互斥锁保护。

为了便于从任何地方登录;记录器是作为单例实现的。

因为实例是一个(静态)指针,指针不会改变;实例不必由互斥锁保护?

我的代码正确吗?

// FileLogger.h:
class FileLogger
{
public:
    static void initialize(const char* filePath) { // called by main thread before any threads are spawned
        instance_ = new FileLogger(filePath);
    }
    static FileLogger* instance() { // called from many threads simultaneously
        return instance_;
    }
    void log(const std::string &msg);
private:
    FileLogger(const char* filePath);
    void writeToFile();
    static FileLogger*     instance_;
    std::deque<std::string> messages;
    std::mutex         messagesMutex; // lock/unlock this each time messages is pushed or popped
    std::ofstream               fout;
    std::thread         writerThread;
};
// FileLogger.cpp:
FileLogger* FileLogger::instance_ = nullptr;

void FileLogger::writeToFile() {
    for (;;) {
        std::string message;
        while (messages.empty()) {
            std::this_thread::sleep_for(std::chrono::nanoseconds(10));
        }
        messagesMutex.lock();
        message = messages.front();
        messages.pop_front();
        messagesMutex.unlock();
        fout << message << std::endl << std::flush;
    }
}

FileLogger::FileLogger(const char* filePath) {
    fout.open(filePath);
    std::thread t(&FileLogger::writeToFile, this);
    writerThread = std::move(t);
}

void FileLogger::log(const std::string &msg) {
    std::lock_guard<std::mutex> lg(messagesMutex);
    messages.push_back(msg);
}