windows C++ 互相等待线程同步示例

浏览数：41 / 时间：2015年06月08日

windows C++ 互相等待线程同步示例

开发中遇到线程同步问题，可抽象为如下模型：
1、主线程的继续执行的前提是子线程的变量已经初始化完毕。
2、子线程待主线程执行完毕后继续执行后续的初始化操作。
重复1,2执行……直到通信结束。

如下图所示：
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源码（VS2010编译、运行通过）

#include "stdafx.h"
#include <iostream>
using namespace std;
#include <windows.h>
const char* g_pszEventName = "GLOBAL/MY_EVENT";  //事件对象的名称
HANDLE g_hSetTaskIdEvent = NULL;                 //全局Event事件

const int g_iMaxRunCnt = 50;                     //最大的运行次数.
/*
**@brief:模拟线程函数。
**@param:LPVOID pParam 线程参数，未使用（可传递结构体指针等）
**@return 0，ok； 其他代表异常退出。
*/
UINT RecvDataThreadProc(LPVOID pParam)
{
 cout << "The RecvDataThreadProc() is Running!" << endl;
 int nThreadCnt = 0;
 while(nThreadCnt < g_iMaxRunCnt)
 {
  printf("[Thread] The TaskId already Setted! RunCnt = %d\n", nThreadCnt++);
  SetEvent(g_hSetTaskIdEvent); //触发,主线程可以运行.
  WaitForSingleObject(g_hSetTaskIdEvent, INFINITE);
 }
 return 0;
}
/*
**@brief:主线程和副线程交替运行。
**
**
*/
int _tmain(int argc, _TCHAR* argv[])
{
 // 启动一个处理线程
 DWORD dwThreadId = 0;
 HANDLE hRecvThread = CreateThread(NULL, //Choose default security
           0,                             //Default stack size
             (LPTHREAD_START_ROUTINE)&RecvDataThreadProc,//Routine to execute
             (LPVOID) NULL,                              //Thread parameter
              0,                                         //Immediately run the thread
             &dwThreadId                                //Thread Id
             );
 if (NULL == hRecvThread)
 {
  printf("CreateThread Failed! ErrCode: %d\n", GetLastError());
  return(1);
 }
 else
 {
  printf("CreateThread OK!\n");
 }
 CloseHandle(hRecvThread);
 //1.创建命名的事件对象,自动且初始化为无信号状态
 g_hSetTaskIdEvent= CreateEvent(NULL, FALSE, FALSE, (LPCWSTR)(g_pszEventName)); 
 int iErrorCode = GetLastError();
 if (ERROR_ALREADY_EXISTS == iErrorCode)
 {
  printf("[Process]CreateEvent() the object is already exist!\n");
 }
 else if (NULL == g_hSetTaskIdEvent)
 {
  printf("[Process] CreateEvent() Error, Errorcode: %d\n", iErrorCode);
 }
 else
 {
  printf("[Process] CreateEvent() Success!\n");
 }

 unsigned int nRunCnt = 0;
 while(nRunCnt < g_iMaxRunCnt)
 {
  bool bRunNext = false;   //初始置为false,不可以执行下面的操作。
  //等待信号触发
  DWORD dwRst = WaitForSingleObject(g_hSetTaskIdEvent, INFINITE);
  switch(dwRst)
  {
  case WAIT_OBJECT_0:
   // The process terminated.
   printf("[Process]The state of the specified object is signaled.\n");
   bRunNext = true;
   break;
  case WAIT_TIMEOUT:
   // The process did not terminate within the given milliseconds.
   printf("[Process]The time-out interval elapsed, and the object‘s state is nonsignaled.\n");
   break;
  case WAIT_FAILED:
   // Bad call to function (invalid handle?)
   printf("[Process]WAIT_FAILED, ErrCode: %d\n", GetLastError());
   break;
  }//end switch
  //主线程运行后才可以执行下面的操作.
  if (bRunNext)
  {
   printf("[Process] The Process() Next can running!, running cnt = %d\n", nRunCnt++);
  }
  SetEvent(g_hSetTaskIdEvent);
 }
 CloseHandle(g_hSetTaskIdEvent);
 return 0;
}