我写了以下代码并在code::blocks中使用mingw gcc 4.7编译它,运行良好。后来我决定开始使用Visual Studio 2013 Express,现在当调用ReadFile()时出现了错误,显示参数无效。我无法找到错误,希望这里有人能发现。
我这样调用WorkThread
这全部包含在一个名为Serial的类中。从IDE中可以看出,与CreateFile()返回的句柄相比,m_hSerial的内存引用是正确的。
m_hSerial = CreateFile(m_pchPort,
GENERIC_READ | GENERIC_WRITE,
0,
0,
OPEN_EXISTING,
FILE_FLAG_OVERLAPPED,
0);
我这样调用WorkThread
m_hThread = (HANDLE)_beginthreadex(0, 0, &WorkThread, (void*) this, 0, 0);
这里是WorkThread的代码
unsigned int __stdcall Serial::WorkThread(void* pvParam)
{
// This is a pointer to the 'this' serial class.
// Needed to be able to set members of the class in a static class function
Serial * cThis = (Serial*) pvParam;
// Set up the overlapped event
OVERLAPPED ov;
memset(&ov, 0, sizeof(ov));
ov.hEvent = CreateEvent(0, true, 0, 0);
DWORD dwEventMask = 0;
DWORD dwWait;
HANDLE aHandles[2];
aHandles[0] = cThis->m_hThreadTerminator;
aHandles[1] = ov.hEvent;
SetEvent(cThis->m_hThreadRunning);
while (true)
{
if (!WaitCommEvent(cThis->m_hSerial, &dwEventMask, &ov))
{
assert(GetLastError() == ERROR_IO_PENDING);
}
dwWait = WaitForMultipleObjects(2, aHandles, FALSE, INFINITE);
switch(dwWait)
{
case WAIT_OBJECT_0:
{
_endthreadex(1);
}
case WAIT_OBJECT_0 + 1:
{
if (dwEventMask & EV_TXEMPTY)
{
ResetEvent(ov.hEvent);
}
else if (dwEventMask & EV_RXCHAR)
{
// read data here
DWORD dwBytesRead = 0;
DWORD dwErrors;
COMSTAT cStat;
OVERLAPPED ovRead;
ovRead.hEvent = CreateEvent(0, true, 0, 0);
// Get the Bytes in queue
ClearCommError(cThis->m_hSerial, &dwErrors, &cStat);
DWORD nSize = cStat.cbInQue;
// EM_REPLACESEL needs a LPARAM null terminated string, make room and set the CString NULL
char *szBuf = new char[nSize+1];
memset(szBuf, 0x00, sizeof(szBuf));
if (!ReadFile(cThis->m_hSerial, &szBuf, nSize, &dwBytesRead, &ovRead))
DWORD err = GetLastError();
if (dwBytesRead == nSize)
SendMessage(cThis->m_hHwnd, WM_SERIAL, 0, LPARAM(&szBuf));
CloseHandle(ovRead.hEvent); // clean up!!!
delete[] szBuf;
}
// Reset the overlapped event
ResetEvent(ov.hEvent);
}
break;
}//switch
}
return 0;
}
ReadFile()
时要解引用szBuf
?通过直接传递szBuf,你隐式地执行了&szBuf[0]
,这应该是调用此函数的正确方法。 - VinzOVERLAPPED ovRead = {};
。 - Hans Passant