我正在使用MFC开发应用程序。UI线程启动工作线程,并在应用程序关闭时将其停止。问题在于,每次尝试删除线程时,应用程序都会崩溃。
这是代码:
首先是线程类及其实现:
class FileThread : public CWinThread
{
public:
static FileThread* CreateWorkerThread(LPVOID params, UINT priority, UINT flags);
void InitThread();
void StopThread();
inline HANDLE GetStopHandle() const { return m_stopThread; }
inline HANDLE GetWaitHandle() const { return m_waitThread; }
private:
HANDLE m_stopThread;
HANDLE m_waitThread;
FileThread(): m_stopThread(NULL), m_waitThread(NULL) { }
static UINT MyThreadProc(LPVOID pParam);
};
FileThread* FileThread::CreateWorkerThread(LPVOID params, UINT priority, UINT flags)
{
return (FileThread*) AfxBeginThread(FileThread::MyThreadProc, params, priority, 0, flags);
}
void FileThread::InitThread()
{
m_stopThread = CreateEvent(0, TRUE, FALSE, 0);
m_waitThread = CreateEvent(0, TRUE, FALSE, 0);
}
void FileThread::StopThread()
{
::SetEvent(m_stopThread);
::WaitForSingleObject(m_waitThread, INFINITE);
::CloseHandle(m_stopThread);
::CloseHandle(m_waitThread);
}
UINT FileThread::MyThreadProc(LPVOID pParam)
{
ThreadData* pLink = (ThreadData*)pParam;
BOOL continueProcess = TRUE;
int returnCode = EXITCODE_SUCCESS;
while (continueProcess)
{
if(::WaitForSingleObject(pLink->pMe->GetStopHandle(), 0) == WAIT_OBJECT_0)
{
::SetEvent(pLink->pMe->GetWaitHandle());
continueProcess = FALSE;
}
// the thread is looking for some files...
}
delete pLink; // it was allocated from the UI thread
return returnCode;
}
然后,在我启动线程的地方:
ThreadData * td = new ThreadData();
m_myFileThread = FileThread::CreateWorkerThread((LPVOID)td, THREAD_PRIORITY_LOWEST, CREATE_SUSPENDED);
td->pMe = m_myFileThread;
m_myFileThread->m_bAutoDelete = FALSE;
m_myFileThread->InitThread();
m_myFileThread->ResumeThread();
最后,停止(以及崩溃):
DWORD exitCode;
if (m_myFileThread != NULL && GetExitCodeThread(m_myFileThread->m_hThread, &exitCode) && (exitCode == STILL_ACTIVE))
{
m_myFileThread->StopThread();
if(::WaitForSingleObject(m_myFileThread->m_hThread, 5000) == WAIT_TIMEOUT)
{
TerminateThread(m_myFileThread->m_hThread, EXITCODE_ABORT);
}
}
if (m_myFileThread != NULL)
{
delete m_myFileThread; // => CRASH
}
看来我尝试删除已删除的内容并最终导致堆损坏。我尝试将m_bAutoDelete设置为TRUE,而不是自己删除线程,因为我遇到了相同的崩溃(该程序试图调用AfxEndThread时)。
线程终止其线程proc并返回退出代码。
在我看来,这里有一个问题:
FileThread* FileThread::CreateWorkerThread(LPVOID params, UINT priority,
UINT flags)
{
return (FileThread*) AfxBeginThread(FileThread::MyThreadProc, params,
priority, 0, flags);
}
AfxBeginThread
返回一个CWinthread*
,因此仅将其强制转换为您自己的派生类并不能使其成为该派生类的实例。我很惊讶它的工作原理。
而不是派生FileThread
从CWinThread
,它可能是更好地去把握一个CWinthread*
你的包装类中的成员变量,并在必要时通过访问露出线程处理。
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我来说两句