关键段

CriticalSection

以原子方式访问。在执行之前独占对一些共享资源的访问权。

-头文件：
Windoes.h
process.h
-定义：
CRITICAL_SECTION cs;
-初始化：
VOID InitializeCriticalSection(&cs);
-删除：
VOID DeleteCriticalSection(&cs);
-进入关键段
VOID EnterCriticalSection(&cs);
BOOL TryEnterCriticalSection(&cs);//这个函数不会等待，如果进不去，就继续向下执行
-离开关键段
VOID LeaveCriticalSection(&cs);

一个小例子

借还书

main函数调用，启动

void OnActive()
{
    HANDLE hThreadRead;
    HANDLE hThreadWrite;

    DWORD dwThreadIDRead,deThreadIDWrite;

    hThreadRead = (HANDLE)_beginthreadex(NULL,0,ThreadFuncRead,NULL,0,(unsigned int*)&dwThreadIDRead);
    hThreadWrite = (HANDLE)_beginthreadex(NULL,0,ThreadFuncWrite,NULL,0,(unsigned int *)&deThreadIDWrite);

    InitializeCriticalSection(&cs);

    Sleep(1000);

    CloseHandle(hThreadRead);
    CloseHandle(hThreadWrite);

    DeleteCriticalSection(&cs);

}

借书操作

int bookNumbers = 10;
CRITICAL_SECTION cs;

unsigned __stdcall ThreadFuncRead(void*)
{
    while(1)
    //for(int i = 0;i<10;i++)
    {
        EnterCriticalSection(&cs);
        if (bookNumbers>0)
        {
            printf("借走一本书，剩余数量:%d\n",--bookNumbers);
            LeaveCriticalSection(&cs);
        }
        else
        {
            LeaveCriticalSection(&cs);
            break;
        }
    }
    return 1;
}

还书操作

unsigned __stdcall ThreadFuncWrite(void*)
{
    while(1)
    //for(int i = 0;i<10;i++)
    {
        EnterCriticalSection(&cs);
        if (bookNumbers<10)
        {
            printf("还回一本书，剩余数量:%d\n",++bookNumbers);
            LeaveCriticalSection(&cs);
        }
        else
        {
            LeaveCriticalSection(&cs);
            break;
        }
    }
    return 1;
    
}