线程间通信

线程间通信

全局变量或类的成员变量

1. 全局变量

定义一个全局变量，开启两个线程一个进行自减，一个进行打印,并使用CCriticalSection类’临界区’进行线程同步。

//CSyncThreadDlg.h
UINT ThreadPoc3(LPVOID pParam);//全局变量 线程函数
UINT ThreadPoc4(LPVOID pParam);
extern UINT g_Num;

public:
CCriticalSection m_cs;//临界区对象


CSyncThreadDlg.h
UINT g_Num = 1000;
void CSyncThreadDlg::OnBnClickedButtonCreateGlobal()
{
	CString str;
	GetDlgItem(IDC_BUTTON_CREATE_GLOBAL)->GetWindowText(str);
	if (_T("创建线程") == str)
	{
		GetDlgItem(IDC_BUTTON_CREATE_GLOBAL)->SetWindowText(_T("退出线程"));
		pGloBalThread3 = AfxBeginThread(ThreadPoc3, NULL);
		pGloBalThread4 = AfxBeginThread(ThreadPoc4, this);
		//更新UI界面
		GetDlgItem(IDC_BUTTON_SUSPEND)->EnableWindow(TRUE);
	}
	else
	{
		GetDlgItem(IDC_BUTTON_CREATE_GLOBAL)->SetWindowText(_T("创建线程"));
		::TerminateThread(pGloBalThread3->m_hThread, 0);
		::TerminateThread(pGloBalThread4->m_hThread, 0);
	}
}

UINT ThreadPoc3(LPVOID pParam)
{
	while (TRUE)
	{
		g_Num--;
		Sleep(500);
	}
	return 0;
}

UINT ThreadPoc4(LPVOID pParam)
{
	CSyncThreadDlg *pDlg = (CSyncThreadDlg *)pParam;
	CString str;
	while (TRUE)
	{
		pDlg->m_cs.Lock();//加锁
		str.Format(_T("%d "), g_Num);
		pDlg->GetDlgItem(IDC_EDIT_GLOBAL)->SetWindowText(str);
		pDlg->m_cs.Unlock();//解锁
		OutputDebugString(str);
		Sleep(500);
	}
	return 0;
}

void CSyncThreadDlg::OnBnClickedButtonSuspend()
{
	CString str;
	GetDlgItem(IDC_BUTTON_SUSPEND)->GetWindowText(str);
	if (_T("挂起") == str)
	{
		GetDlgItem(IDC_BUTTON_SUSPEND)->SetWindowText(_T("唤醒"));
		SuspendThread(pGloBalThread3->m_hThread);//挂起线程
		SuspendThread(pGloBalThread4->m_hThread);
	}
	else
	{
		GetDlgItem(IDC_BUTTON_SUSPEND)->SetWindowText(_T("挂起"));
		ResumeThread(pGloBalThread3->m_hThread);//唤醒线程
		ResumeThread(pGloBalThread4->m_hThread);
	}
}

2. 类的成员变量

定义一个类的成员函数，开启两个线程一个进行自增，一个进行打印

//创建线程与退出线程
void CSyncThreadDlg::OnBnClickedButtonClassCreate()
{
	CString str;
	GetDlgItem(IDC_BUTTON_CLASS_CREATE)->GetWindowText(str);
	if (_T("创建线程") == str)
	{
		GetDlgItem(IDC_BUTTON_CLASS_CREATE)->SetWindowText(_T("退出线程"));
		pClassThread1 = AfxBeginThread(ThreadPoc1, this);
		pClassThread2 = AfxBeginThread(ThreadPoc2, this);
		m_Num = 0;
		//更新UI界面
		GetDlgItem(IDC_BUTTON_CLASS_SUPEND)->EnableWindow(TRUE);
	}
	else
	{
		GetDlgItem(IDC_BUTTON_CLASS_CREATE)->SetWindowText(_T("创建线程"));
		//TerminateThread以异步方式执行,函数返回不代表线程结束,
		//线程函数停止执行，位置随机，类对象不会被析构导致内存泄漏
		::TerminateThread(pClassThread1->m_hThread, 0);
		::TerminateThread(pClassThread2->m_hThread, 0);
	}	
}

UINT CSyncThreadDlg::ThreadPoc1(LPVOID pParam)
{
	CSyncThreadDlg *pDlg = (CSyncThreadDlg *)pParam;
	while (TRUE)
	{
		++(pDlg->m_Num);
		Sleep(500);
	}
	return 0;
}

UINT CSyncThreadDlg::ThreadPoc2(LPVOID pParam)
{
	CSyncThreadDlg *pDlg = (CSyncThreadDlg *)pParam;
	CString str;
	while (TRUE)
	{
		pDlg->m_cs.Lock();//加锁
		str.Format(_T("%d "), pDlg->m_Num);
		pDlg->GetDlgItem(IDC_EDIT_CLASS)->SetWindowText(str);
		pDlg->m_cs.Unlock();//解锁
		OutputDebugString(str);
		Sleep(500);
	}
	return 0;
}


void CSyncThreadDlg::OnBnClickedButtonClassSupend()
{
	CString str;
	GetDlgItem(IDC_BUTTON_CLASS_SUPEND)->GetWindowText(str);
	if (_T("挂起") == str)
	{
		GetDlgItem(IDC_BUTTON_CLASS_SUPEND)->SetWindowText(_T("唤醒"));
		SuspendThread(pClassThread1->m_hThread);//挂起线程
		SuspendThread(pClassThread2->m_hThread);
	}
	else
	{
		GetDlgItem(IDC_BUTTON_CLASS_SUPEND)->SetWindowText(_T("挂起"));
		ResumeThread(pClassThread1->m_hThread);//唤醒线程
		ResumeThread(pClassThread2->m_hThread);
	}
}

发消息方式

该方式需要自定义消息和绑定，然后一个线程进行消息的发送，而另一个线程不停的接收自定义的的消息，一接收到立马执行。

//方式三:使用创建发消息的方式进行通信
void CSyncThreadDlg::OnBnClickedButtonSendMsgCreate()
{
	CWinThread *pThreadPrint = AfxBeginThread(ThreadPrintProc, this);//输出打印线程
	CWinThread *pThreadWrite = AfxBeginThread(ThreadWriteProc, (LPVOID)pThreadPrint->m_nThreadID);
}

#define MY_THREAD_MSG (WM_USER+100) //自定义的消息

UINT CSyncThreadDlg::ThreadWriteProc(LPVOID pParam)
{
	UINT nCount = 0;
	DWORD dwThreadReadID = (DWORD)pParam;//线程ID号
	while (true)
	{
		//线程ID号  自动消息ID  消息参数
		PostThreadMessage(dwThreadReadID, MY_THREAD_MSG, nCount++, NULL);
		Sleep(500);
	}
	return 0;
}
//接收消息线程
UINT CSyncThreadDlg::ThreadPrintProc(LPVOID pParam)
{
	CSyncThreadDlg *pDlg = (CSyncThreadDlg*)pParam;

	MSG msg = { 0 };
	while (GetMessage(&msg,0,0,0))
	{
		switch (msg.message)
		{
		case MY_THREAD_MSG:
			{
				pDlg->m_cs.Lock();//加锁
				UINT nCount = (int)msg.wParam;
				CString str;
				str.Format(_T("%d "), nCount);
				pDlg->GetDlgItem(IDC_EDIT_SENDMESSAGE)->SetWindowText(str);
				pDlg->m_cs.Unlock();//解锁
				OutputDebugString(str);
				Sleep(500);
			}
			break;
		default:
			break;
		}
	}
	return 0;
}