关于CreateMutex的疑问？？？

[wangsiyuanoo]

下面的代码 我的理解是：

比如先进线程3，那线程3就拥有g_hMutex，线程4就阻塞在了WaitForSingleObject里，执行不下去，必须等到线程3释放掉了g_hMutex，线程4才能执行下去

程序运行的效果却有点让我模糊了

结果1：正常。线程3执行了ReleaseMutex，线程4才运行WaitForSingleObject下面的代码

结果2：一开始线程3和线程4一起执行WaitForSingleObject下面的代码一次！然后，线程3或线程4才有结果1的效果

为什么会出现这种情况，是我一开始的理解就不对么？

int iTickets = 3;
HANDLE g_hMutex;
unsigned __stdcall Thread3( void * obj )
{
	while ( TRUE )
	{
		//先进来 
		//Thread3先拥有g_hMutex

		WaitForSingleObject( g_hMutex, INFINITE );
		if ( iTickets > 0 )
		{
			cout << "Thread3: " << iTickets-- << endl;
		}
		else
		{
			ReleaseMutex( g_hMutex );
			break;
		}
	}

	return 0;
}

unsigned __stdcall Thread4( void * obj )
{
	while ( TRUE )
	{
		//后进来 
		//需要等待Thread3释放g_hMutex，Thread4才能拥有g_hMutex

		WaitForSingleObject( g_hMutex, INFINITE );
		if ( iTickets > 0 )
		{
			cout << "Thread4: " << iTickets-- << endl;
		}
		else
		{
			ReleaseMutex( g_hMutex );
			break;
		}
	}
	return 0;
}

void Test_Mutex()
{
	HANDLE hThread3 = (HANDLE)_beginthreadex( NULL, 0, Thread3, NULL, 0, NULL );
	HANDLE hThread4 = (HANDLE)_beginthreadex( NULL, 0, Thread4, NULL, 0, NULL );
	CloseHandle( hThread3 );
	CloseHandle( hThread4 );

	g_hMutex = CreateMutex( NULL, FALSE, NULL );
}

[kyotrue]

先创建了再使用！

g_hMutex = CreateMutex( NULL, FALSE, NULL );

HANDLE hThread3 = (HANDLE)_beginthreadex( NULL, 0, Thread3, NULL, 0, NULL );
HANDLE hThread4 = (HANDLE)_beginthreadex( NULL, 0, Thread4, NULL, 0, NULL );
CloseHandle( hThread3 );
CloseHandle( hThread4 );

[wangsiyuanoo]

[Quote=引用 1 楼 kyotrue 的回复:]
先创建了再使用！

g_hMutex = CreateMutex( NULL, FALSE, NULL );

HANDLE hThread3 = (HANDLE)_beginthreadex( NULL, 0, Thread3, NULL, 0, NULL );
HANDLE hThread4 = (HANDLE)_beginthreadex( NULL, 0, Threa……
[/Quote]

哦 您的意思是说 我先创建了线程 那么线程就启动了 就会出现同时运行两个线程的情况 是么？

[wangsiyuanoo]

还有个问题

死锁 这个名字 有点难理解

能举个列子 说明 什么才叫死锁么？？？

[Eleven]

死锁 这个名字 有点难理解

能举个列子 说明 什么才叫死锁么？？？
-----------------------------
很简单，在主线程中创建线程，然后WaitForSingleObject()等待线程结束，在创建的子线程中SendMessage给UI窗口发送消息，这样就死锁了

[Eleven]

#include <iostream>
#include <process.h>
using namespace std;

int iTickets = 4;
HANDLE g_hMutex;
unsigned __stdcall Thread3( void * obj )
{
    while ( TRUE )
    {
        //ÏȽøÀ´ 
        //Thread3ÏÈÓµÓÐg_hMutex
		
        WaitForSingleObject( g_hMutex, INFINITE );
        if ( iTickets > 0 )
        {
            cout << "Thread3: " << iTickets-- << endl;
        }
        else
        {
            ReleaseMutex( g_hMutex );
            break;
        }
		ReleaseMutex( g_hMutex );
    }
	
    return 0;
}

unsigned __stdcall Thread4( void * obj )
{
    while ( TRUE )
    {
        //ºó½øÀ´ 
        //ÐèÒªµÈ´ýThread3ÊÍ·Åg_hMutex£¬Thread4²ÅÄÜÓµÓÐg_hMutex
		
        WaitForSingleObject( g_hMutex, INFINITE );
        if ( iTickets > 0 )
        {
            cout << "Thread4: " << iTickets-- << endl;
        }
        else
        {
            ReleaseMutex( g_hMutex );
            break;
        }
		ReleaseMutex( g_hMutex );
    }
    return 0;
}

void Test_Mutex()
{
	g_hMutex = CreateMutex( NULL, FALSE, NULL );

    HANDLE hThread3 = (HANDLE)_beginthreadex( NULL, 0, Thread3, NULL, 0, NULL );
    HANDLE hThread4 = (HANDLE)_beginthreadex( NULL, 0, Thread4, NULL, 0, NULL );

	WaitForSingleObject(hThread3, INFINITE);
	WaitForSingleObject(hThread4, INFINITE);
    CloseHandle( hThread3 );
    CloseHandle( hThread4 );  
}

int main()
{
	Test_Mutex();
	return 0;
}

[wangsiyuanoo]

void Test_Mutex()
{
    g_hMutex = CreateMutex( NULL, FALSE, NULL );

    HANDLE hThread3 = (HANDLE)_beginthreadex( NULL, 0, Thread3, NULL, 0, NULL );
    HANDLE hThread4 = (HANDLE)_beginthreadex( NULL, 0, Thread4, NULL, 0, NULL );

    //这是等待线程3和4的结束，和死锁有什么关系？
    WaitForSingleObject(hThread3, INFINITE);
    WaitForSingleObject(hThread4, INFINITE);
    
    CloseHandle( hThread3 );
    CloseHandle( hThread4 );  
}

[maoxing63570]

死锁，你还是就去找本操作系统的书看下吧

[竞天问]

跟变速箱的“乱档”差不多啊，不过你熟不熟悉机械我就不知道了