C++多线程读写文件

std::mutex mt_;

std::string LoadFile(const std::string &path) {
    std::unique_lock<std::mutex> lck(mt_);
    std::ifstream fin(path);
    std::string str((std::istreambuf_iterator<char>(fin)),
                    std::istreambuf_iterator<char>());
    return str;
}

int WriteFile(const std::string &path, const std::string &content) {
    std::unique_lock<std::mutex> lck(mt_);
    int ret = -1;
    do {
        std::ofstream out;
        out.open(path, std::ios::trunc);
        if (!out.is_open())
            break;

        out << content;
        out.close();

        ret = 0;
    } while (0);

    return ret;
}