线程操作C++封装

Posted 2021-07-29 奇妙之二进制

C++11标准已经引入了线程操作，这里为了练习，我们尝试自行封装基于phread库的线程操作。

这里的写法有点类似与Java的线程。创建线程需要继承于我们写的Thread类。

#include "base/thread.h"

Thread::Thread() : arg_(NULL), start_(false), detach_(false) {}

Thread::~Thread() {
  if (start_ == true && detach_ == false) Detach();
}

bool Thread::Start(void *arg) {
  arg_ = arg;

  if (pthread_create(&thread_id_, NULL, ThreadRun, this)) return false;

  start_ = true;
  return true;
}

bool Thread::Detach() {
  if (start_ != true) return false;

  if (detach_ == true) return true;

  if (pthread_detach(thread_id_)) return false;

  detach_ = true;

  return true;
}

bool Thread::Join() {
  if (start_ != true || detach_ == true) return false;

  if (pthread_join(thread_id_, NULL)) return false;

  return true;
}

bool Thread::Cancel() {
  if (start_ != true) return false;

  if (pthread_cancel(thread_id_)) return false;

  start_ = false;

  return true;
}

pthread_t Thread::GetThreadId() const { return thread_id_; }

void *Thread::ThreadRun(void *arg) {
  Thread *thread = (Thread *)arg;
  thread->Run(thread->arg_);
  return NULL;
}

#ifndef _THREAD_H_
#define _THREAD_H_

#include <pthread.h>

class Thread {
 public:
  virtual ~Thread();

  bool Start(void *arg);
  bool Detach();
  bool Join();
  bool Cancel();
  pthread_t GetThreadId() const;

 protected:
  Thread();

  virtual void Run(void *arg) = 0;

 private:
  static void *ThreadRun(void *);

 private:
  void *arg_;
  bool start_;
  bool detach_;
  pthread_t thread_id_;
};

#endif  //_THREAD_H_

测试程序：

#include "base/thread.h"

#include <unistd.h>

#include <iostream>

class MyThread : public Thread {
  void Run(void *arg) {
    while (1) {
      std::cout << "test, arg = " << *(int *)arg << std::endl;
      sleep(1);
    }
  }
};

int main() {
  MyThread thread;
  int a = 11;
  thread.Start(&a);
  thread.Join();
}

上面的实现缺点非常多，一是参数只能传一个，另外不能直接绑定函数，创建线程还需要自己去实现一个类继承于Thread，十分不灵活。