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

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;
}