muduo_base代码剖析之线程本地单例对象ThreadLocalSingleton

版权声明：guojawee https://blog.csdn.net/weixin_36750623/article/details/84327402

线程本地单例对象的封装ThreadLocalSingleton<T>，也就是说，每一个线程都有一个T类型的单例对象

---

直接看测试代码

#include <muduo/base/ThreadLocalSingleton.h>
#include <muduo/base/CurrentThread.h>
#include <muduo/base/Thread.h>

#include <stdio.h>

class Test : muduo::noncopyable
{
public:
  Test()
  {
    printf("tid=%d, constructing %p\n", muduo::CurrentThread::tid(), this);
  }

  ~Test()
  {
    printf("tid=%d, destructing %p %s\n", muduo::CurrentThread::tid(), this, name_.c_str());
  }

  const muduo::string& name() const { return name_; }
  void setName(const muduo::string& n) { name_ = n; }

private:
  muduo::string name_;
};

void threadFunc(const char* changeTo)
{
  printf("tid=%d, %p name=%s\n",
         muduo::CurrentThread::tid(),
         &muduo::ThreadLocalSingleton<Test>::instance(),
         muduo::ThreadLocalSingleton<Test>::instance().name().c_str());
  muduo::ThreadLocalSingleton<Test>::instance().setName(changeTo);
  printf("tid=%d, %p name=%s\n",
         muduo::CurrentThread::tid(),
         &muduo::ThreadLocalSingleton<Test>::instance(),
         muduo::ThreadLocalSingleton<Test>::instance().name().c_str());

  // no need to manually delete it
  // muduo::ThreadLocalSingleton<Test>::destroy();
}


int main()
{
//muduo::ThreadLocalSingleton<Test>::instance()单例对象是每个线程都有一份，即每个线程都有一个Test对象
//与上一章节看到的完全不一样

  //主线程中，叫main one
  muduo::ThreadLocalSingleton<Test>::instance().setName("main one");
  //线程1中，叫thread1
  muduo::Thread t1(std::bind(threadFunc, "thread1"));
  //线程2中，叫thread2
  muduo::Thread t2(std::bind(threadFunc, "thread2"));
  t1.start();
  t2.start();
  t1.join();
  printf("tid=%d, %p name=%s\n",
         muduo::CurrentThread::tid(),
         &muduo::ThreadLocalSingleton<Test>::instance(),
         muduo::ThreadLocalSingleton<Test>::instance().name().c_str());
  t2.join();

  pthread_exit(0);
}