为什么信号量被释放但 WaitForSingleObject() 仍然卡住？

Question

更新：我发现他们正在释放的信号量不是监视线程正在等待的信号量！我使用 cout<<ready 发现线程正在释放的信号量是 00000394，这不是监视线程正在等待的信号量的句柄。这个问题的可能原因是什么？谢谢！

我是 Windows 的多线程编程新手。今天在写我的在线游戏服务器时，我尝试在Windows中使用信号量。它基于 IOCP 编写，因此每条消息都在单独的线程中处理。一场比赛由 4 名玩家组成。

我期望它做的是：当收到一条消息时，一个新的线程启动并释放一个ready。有个监听线程等待4ready，然后释放4all_ready。每个线程等待一个 all_ready 并继续。

代码在这里：

CGameHost 是 4 人游戏的经理。

CGameHost::CGameHost(void)
{
    init_times=0;
    ready = CreateSemaphore(NULL, 0, 4, NULL);
    read = CreateSemaphore(NULL, 0, 4, NULL);
    all_ready = CreateSemaphore(NULL, 0, 4, NULL);
    all_read = CreateSemaphore(NULL, 0, 4, NULL);
    monitor_thread = (HANDLE)_beginthreadex(NULL, 0, Monitor, (LPVOID)this, NULL, 0);
}

unsigned __stdcall CGameHost::Monitor( LPVOID p ) // a static function
{
    CGameHost *nowp = (CGameHost *)p;
    while(true)
    {
        int i;
        for(i=1;i<=MAX_PLAYER;i++)
        {
            WaitForSingleObject(nowp->ready, INFINITE);//stuck here
            cout<<"Get Ready!"<<endl; // This is not outputed, which means it stucks in the last row.
        }

        for(i=1;i<=MAX_PLAYER;i++)
        {
            ReleaseSemaphore(nowp->all_ready, 1, NULL);
        }

        for(i=1; i<=MAX_PLAYER; i++)
        {
            WaitForSingleObject(nowp->read, INFINITE);
        }

        for(i=1; i<=MAX_PLAYER;i++)
        {
            ReleaseSemaphore(nowp->all_read, 1, NULL);
        }
    }
    return 0;
}

void CGameHost::ReleaseReady()
{
    ReleaseSemaphore(ready, 1, NULL);
}

void CGameHost::WaitAllReady()
{
    WaitForSingleObject(all_ready, INFINITE);
}

void CGameHost::ReleaseRead()
{
    ReleaseSemaphore(read, 1, NULL);
}

void CGameHost::WaitAllRead()
{
    WaitForSingleObject(all_read, INFINITE);
}

DataProcess::Game 是传入游戏消息的消息处理程序。

CMessage Dataprocess::Game( CMessage* recv_msg )
{
    CMessage ret;
    int now_roomnum = recv_msg->para1;
    int now_playernum = recv_msg->para2;
    if(true)
    {
        cout<<"Received Game Message: "<<endl;
        cout<<"type2 = "<<recv_msg->type2;
        cout<<" player_num = "<<now_playernum<<" msg= "<<recv_msg->msg<<endl;
    }

    if(recv_msg->type2 == MSG_GAME_OPERATION)
    {
        ret.type1 = MSG_GAME;
        ret.type2 = MSG_GAME_OPERATION;

        cout<<"Entered from "<<now_playernum<<endl;

        game_host[now_roomnum].SetMessage(now_playernum, recv_msg->msg);
        game_host[now_roomnum].ReleaseReady();

        cout<<"Released Ready from "<<now_playernum<<endl;//this is shown

        game_host[now_roomnum].WaitAllReady();//stuck here

        cout<<"AllReady from"<<now_playernum<<endl;//not shown

    }
    return ret;
}

您的回复对我这样的Windows多线程程序员初学者有很大的帮助！谢谢！

Answer 1

如果我了解您的需求，您可能应该有这样的东西..

处理 hPlayersReady[4]；处理 hAllPlayed;

创建这 5 个事件，然后在您的监视器线程上，做这样的事情...

while(true)
{
// Wait for all players to move
WaitForMultipleObjects(4, &hPlayersReady, true, INFINITE);
// Process move
...
// Advise players the move was processed...
SetEvent(hAllPlayed);
}

在你的播放器线程 X

while(true)
{
// Make my move
...
// Advise monitor I'm ready
SetEvent(hPlayersReady[X]);
// Wait for ready to do another move
WaitForSingleObject(hAllPlayed);
}

Answer 2

嗯，我自己解决了。原因是我在创建线程后又使用了CreateSemaphore，让播放器线程访问不同的信号量作为监听线程...对不起我的愚蠢，谢谢你告诉我这么多！

为什么信号量被释放但 WaitForSingleObject() 仍然卡住？

Why semaphore is released but WaitForSingleObject() still stuck?

c++

windows

multithreading

semaphore