线程中进行WaitCommEvent(_hCommHandle, &dwMask, NULL)等待串口数据，此时如果使用任务管理器结束进程，可程序依然挂在上面。如何处理？

Question

串口调试器显示串口并没有关闭 HANDLE _hCommHandle = ::CreateFile(
"\\\\.\\COM3",
GENERIC_READ | GENERIC_WRITE,
0,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED,
NULL  );
        if(!::SetCommMask(_hCommHandle, EV_RXCHAR | EV_ERR))
return ; COMSTAT Stat;
DWORD dwError; DWORD dwMask=EV_RXCHAR | EV_ERR;
DWORD dwLength;
for(;;)
{
if(!::WaitCommEvent(_hCommHandle, &dwMask, NULL))
{

if(dwMask & EV_ERR) // == EV_ERR
::ClearCommError(_hCommHandle, &dwError, &Stat); if(dwMask & EV_RXCHAR) // == EV_RXCHAR
{
::ClearCommError(_hCommHandle, &dwError, &Stat);

                                   //recv
}
        }

Answer 1

你打开串口时使用异步方式，而你等待串口事件是用同步方式。线程无限循环中，WaitCommEvent(...)无限等待中，没有终止。

Answer 2

即使异步也不行。请看代码。
正常关闭程序没有问题，可是在任务管理器-〉进程-〉结束进程 会看到线程少了一个但还保留一个，程序界面几经消失，可进程依然存在，必须禁用串口再起用，进程才消失。
OVERLAPPED _WaitOverlapped;  memset(&_WaitOverlapped, 0, sizeof(_WaitOverlapped));
_WaitOverlapped.hEvent = ::CreateEvent(NULL, true, false, NULL);
HANDLE _hCommHandle = ::CreateFile(
"\\\\.\\COM3",
GENERIC_READ | GENERIC_WRITE,
0,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED,
NULL  );
        if(!::SetCommMask(_hCommHandle, EV_RXCHAR | EV_ERR))
return ; COMSTAT Stat;
DWORD dwError; DWORD dwMask=EV_RXCHAR | EV_ERR;
DWORD dwLength;
for(;;)
{
if(!::WaitCommEvent(_hCommHandle, &dwMask, &WaitOverlapped))
{

                              if(::GetLastError() == ERROR_IO_PENDING)
{//线程会一直阻塞在这里
::GetOverlappedResult(hCommHandle, &_WaitOverlapped, &dwLength, TRUE);
}
if(dwMask & EV_ERR) // == EV_ERR
::ClearCommError(_hCommHandle, &dwError, &Stat); if(dwMask & EV_RXCHAR) // == EV_RXCHAR
{
::ClearCommError(_hCommHandle, &dwError, &Stat);

                                   //recv
}
        }