重叠IO机制

SendData(const char* buf, size_t size)
{
try
{
CEvent event(FALSE, TRUE);
OVERLAPPED overlapped;
ZeroMemory(&overlapped, sizeof(OVERLAPPED));
overlapped.hEvent = event;
if(!m_COM.Write(buf, size, overlapped))
{
DWORD dwBytesWritten;
if(WaitForSingleObject(event, 500) == WAIT_OBJECT_0)
m_COM.GetOverlappedResult(overlapped, dwBytesWritten, TRUE);
}
} catch(CSerialException& e)
{
AfxMessageBox(e.what());
}
}