【语言-C++】多线程通同步临界区 CCriticalSection 与 CSingleLock

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最新推荐文章于 2025-06-04 13:44:08 发布

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本文介绍了一个基于相机处理和显示分离的多线程应用案例。通过使用事件和临界区来实现线程间的同步与互斥。具体包括创建线程、事件处理逻辑以及线程关闭等关键环节。

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多线程通同步与互斥示例

下面示例是一个相机处理和显示分开的两个线程：

定义临界区使用单锁

#define _CRITICAL_LOCK(critical_lock)			CSingleLock locker(&critical_lock);	locker.Lock();
CCriticalSection _critical_data2;

启动线程，创建四个事件：停止线程事件、处理图像事件、显示图像事件和接收图像事件

停止线程事件：线程接受自动复位，初始状态为无信号状态；控制两个线程同时结束

处理图像事件：手动复位，初始状态为无信号状态；

显示图像事件：手动复位，初始状态为无信号状态；

接收图像事件：手动复位，初始状态为有信号状态；

处理图像事件和显示图像事件同时发生时，激活图像处理线程，进行图像处理；接收图像事件的时间的触发由显示图像完成后触发；处理图像事件由相机线程图像传输来触发；

显示图像事件发生时激活显示图像线程进行图像处理。

创建线程

void CMainDlgEx::StartThread()
{
	m_EventStop			= CreateEvent(NULL,TRUE,FALSE,NULL);
	m_EventDealImage		= CreateEvent(NULL,FALSE,FALSE,NULL);
	m_EventImageShow		 = CreateEvent(NULL,FALSE,FALSE,NULL);
	m_EventAllowReceiveImage = CreateEvent(NULL,FALSE,TRUE,NULL);
	// auxiliary methods
	ResetEvent(m_EventStop);
	SetEvent(m_EventAllowReceiveImage);
	// 启动三个线程 
	m_HTDealImage = (HANDLE)_beginthreadex(NULL,								
		0,								
		(unsigned (__stdcall *)(void*))	&Thread_DealImage,
		this,					
		0,					
		&m_IDDealImage);			

	m_HTShowImage = (HANDLE)_beginthreadex(NULL,					
		0,					
		(unsigned (__stdcall *)(void*))&Thread_ShowImage,	
		this,					
		0,					
		&m_IDShowImage);					
}

关闭线程

void CMainDlgEx::CloseThread()
{  
	SetEvent(m_EventStop);       
	WaitForSingleObject(m_HTShowImage,INFINITE);
	WaitForSingleObject(m_HTDealImage,INFINITE);
	if (m_EventStop!=NULL &&m_EventStop !=INVALID_HANDLE_VALUE)
		CloseHandle(m_EventStop);
	if (m_EventDealImage!=NULL &&m_EventDealImage !=INVALID_HANDLE_VALUE)
		CloseHandle(m_EventDealImage);
	if (m_EventAllowReceiveImage!=NULL &&m_EventAllowReceiveImage !=INVALID_HANDLE_VALUE)
		CloseHandle(m_EventAllowReceiveImage );
	if (m_EventImageShow!=NULL &&m_EventImageShow !=INVALID_HANDLE_VALUE)
		CloseHandle(m_EventImageShow);
	DeleteCriticalSection(&m_DealImageMutex);
}

处理线程

void Thread_DealImage(LPVOID *lpParam)
{
	OutputDebugString(_T("处理中 ....启动\n"));
	HANDLE      eventHandle[2];
	CMainDlgEx *MultiThrDlg = (CMainDlgEx*) lpParam;	

	eventHandle[0] = (*MultiThrDlg).m_EventAllowReceiveImage; 
	eventHandle[1] = (*MultiThrDlg).m_EventDealImage;  

	while (WAIT_OBJECT_0 != WaitForSingleObject((MultiThrDlg->m_EventStop),0))
	{
		//抓取数据到grabData中
		while (WAIT_OBJECT_0 == WaitForMultipleObjects(2,eventHandle,TRUE,0))
		{
			_CRITICAL_LOCK(_critical_data2);
			OutputDebugString(_T("处理中 ....\n"));
			SetEvent(MultiThrDlg->m_EventImageShow);
		}
	}
	ResetEvent(MultiThrDlg->m_EventDealImage);
	ResetEvent(MultiThrDlg->m_EventAllowReceiveImage);
	OutputDebugString(_T("处理中 ....退出\n"));
	return;
}

显示线程

extern void Thread_ShowImage( LPVOID *lpParam )
{
	HANDLE      eventHandle[2];
	CMainDlgEx *MultiThrDlg = (CMainDlgEx*) lpParam;	
	OutputDebugString(_T("显示中 ....启动\n"));
	while (WAIT_OBJECT_0 != WaitForSingleObject((MultiThrDlg->m_EventStop),0))
	{
		//抓取数据到grabData中
		while (WAIT_OBJECT_0 == WaitForSingleObject((MultiThrDlg->m_EventImageShow),0))
		{
			_CRITICAL_LOCK(_critical_data2);
			OutputDebugString(_T("显示中 ....\n"));
			SetEvent(MultiThrDlg->m_EventAllowReceiveImage);
		}
	}
	ResetEvent(MultiThrDlg->m_EventImageShow);
	ResetEvent(MultiThrDlg->m_EventAllowReceiveImage);
	OutputDebugString(_T("显示中 ....退出\n"));
	return;
}

数据到达

LRESULT CMainDlgEx::OnCameraDataArrive(WPARAM w, LPARAM l)	
{
	SetEvent(m_EventDealImage);
	return -1;
}