使用者模式下線程同步之關鍵段

使用者模式下線程同步之關鍵段

//注意其中的: InitializeCriticalSection是必須的,否則會報訪問異常

 

// mycrical_section.cpp : Defines the entry point for the application.

//

 

#include "stdafx.h"

 

 

const int count=10;

 

int g_nSum =0;

CRITICAL_SECTION g_cs;

 

DWORD WINAPI FirstThread(PVOID pvParam)

{

         EnterCriticalSection(&g_cs);

         g_nSum =0;

         for(int n=1;n<=count;n++)

         {

                   g_nSum +=n;

         }

         LeaveCriticalSection(&g_cs);

        

         return g_nSum;

}

 

DWORD WINAPI SecondThread(PVOID pvParam)

{

         EnterCriticalSection(&g_cs);

         g_nSum =0;

         for(int n=1;n<=count;n++)

         {

                   g_nSum +=n;

         }

         LeaveCriticalSection(&g_cs);

        

         return g_nSum;

}

 

int APIENTRY WinMain(HINSTANCE hInstance,

                     HINSTANCE hPrevInstance,

                     LPSTR     lpCmdLine,

                     int       nCmdShow)

{

         // TODO: Place code here.

        

        

         DWORD dwThreadId1=0;

         DWORD dwThreadId2=0;

         InitializeCriticalSection(&g_cs);  
//初始化，不加會報訪問異常

        

         CreateThread(NULL,0UL,FirstThread,NULL,0,&dwThreadId1);

         CreateThread(NULL,0UL,SecondThread,NULL,0,&dwThreadId2);

         Sleep(50);

         DeleteCriticalSection(&g_cs);  //清理工作

         return 0;

}