程式很簡單，使用兩個執行緒對一個全域性變數輪流進行累加。

先來看pthread的版本：

#include <pthread.h>
#include <stdio.h>

pthread_mutex_t lock;
pthread_cond_t cond;

int condition=0;
unsigned long long  g_count=0;

void work1(void * arg)
{
  while (1)
  {
    pthread_mutex_lock(&lock);
    while (condition==1)
    {
      pthread_cond_wait(&cond, &lock);
    }
    condition=1;
    g_count++;
    printf("thread %lld working.current num is %d\n",pthread_self(),g_count);
    pthread_cond_signal(&cond);
    pthread_mutex_unlock(&lock);
  }

}

void work2(void * arg)
{
  while (1)
  {
    pthread_mutex_lock(&lock);
    while (condition==0)
    {
      pthread_cond_wait(&cond, &lock);
    }
    condition=0;
    g_count++;
    printf("thread %lld working.current num is %d\n",pthread_self(),g_count);
    pthread_cond_signal(&cond);
    pthread_mutex_unlock(&lock);
  }

}

int main(int argc, char const *argv[])
{
  pthread_t t1,t2;
  pthread_mutex_init(&lock, NULL);
  pthread_cond_init(&cond, NULL);

  pthread_create(&t1, NULL, work1, NULL);
  pthread_create(&t2, NULL, work2, NULL);
  pthread_join(t1, NULL);
  pthread_join(t2, NULL);

  pthread_mutex_destroy(&lock);
  pthread_cond_destroy(&cond);
  return 0;
}
 

#include <iostream>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <chrono>

using namespace std;
using namespace std::chrono;
mutex mtx;
condition_variable cond;
int condition =0;
long long g_count=0;

void work1()
{
  while (1)
  {
    {
      unique_lock<mutex> lck(mtx);
      while (condition==1)
      {
        cond.wait(lck);
      }
    }

    std::lock_guard<mutex> lkgrd(mtx);
    g_count++;
    cout<<"thread"<<this_thread::get_id()<<"is working. "<<" current num is "<< g_count<<endl;
    condition=1;
    cond.notify_all();
  }

}

void work2()
{
  while (1)
  {
    {
      unique_lock<mutex> lck(mtx);
      while (condition==0)
      {
        cond.wait(lck);
      }
    }

    std::lock_guard<mutex> lkgrd(mtx);
    g_count++;
    cout<<"thread"<<this_thread::get_id()<<"is working. "<<" current num is "<< g_count<<endl;
    condition=0;
    cond.notify_all();
  }

}

int main()
{
  thread t1(work1);
  thread t2(work2);

  t1.join();
  t2.join();
}
 

PS：C++11 中執行緒庫風格與pthread類似。和win32 thread 有區別。win32 thread中沒有條件變數這個概念，與之對應的是事件（EVENT）。