Windows线程（六）使用事件机制解决线程同步问题

事件相关函数：

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1.创建事件：CreateEvent
HANDLE CreateEvent
(
    LPSECURITY_ATTRIBUTES lpEventAttributes,
    BOOL bManualReset,
    BOOL bInitialState,
    LPCTSTR lpName
);
2.根据时间名称获得事件句柄：OpenEvent
HANDLE OpenEvent
(
    DWORD dwDesiredAccess,
    BOOL bInheritHandle,
    LPCTSTR lpName
);
3.触发事件：SetEvent
BOOL SetEvent(HANDLE hEvent);
4.将事件设置为未触发：ResetEvent
BOOL ResetEvent(HANDLE hEvent);
5.将被触发后的事件立即设置为未触发：PulseEvent
BOOL PulseEvent(HANDLE hEvent);

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使用事件机制解决线程同步问题测试代码：

#include <stdio.h>
#include <process.h>
#include <Windows.h>

#define THREAD_NUM 10

unsigned long g_nNum;
//事件与关键段
HANDLE g_hThreadEvent;
CRITICAL_SECTION g_csThreadCode;

unsigned int __stdcall ThreadFun(void *pM)
{
    int nThreadNum = *(int *)pM;

    //触发事件
    SetEvent(g_hThreadEvent);
    Sleep(50);

    EnterCriticalSection(&g_csThreadCode);
    g_nNum++;

    Sleep(0);
    printf("线程编号为%d 全局资源值为%d\n", nThreadNum, g_nNum);

    LeaveCriticalSection(&g_csThreadCode);
    return 0;
}

int main()
{
    int i = 0;
    HANDLE handle[THREAD_NUM];
    printf("--------------------经典线程同步之事件--------------------\n");

    //初始化事件和关键段， 自动置位，初始化无触发的匿名事件
    g_hThreadEvent = CreateEvent(NULL, 0, 0, NULL);
    InitializeCriticalSection(&g_csThreadCode);
    g_nNum = 0;

    while(i < THREAD_NUM)
    {
        handle[i] = (HANDLE)_beginthreadex(NULL, 0, ThreadFun, &i, 0, NULL);
        //等待事件被触发
        WaitForSingleObject(g_hThreadEvent, INFINITE);
        i++;
    }

    WaitForMultipleObjects(THREAD_NUM, handle, 1, INFINITE);

    //销毁事件和关键段
    CloseHandle(g_hThreadEvent);
    DeleteCriticalSection(&g_csThreadCode);

    system("pause");

    return 0;
}

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以上代码在Visual Studio 2010中的运行结果如下：

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由此可见，使用事件机制和关键段，终于解决了线程同步与互斥的问题。