Windows MFC worker thread cannot quit - windows

Question

I want to show the stdout of commandline program in MFC edit control. So I start a worker thread by AfxBeginThread to update the UI by PostMessage (this part works great), and the worker thread communicates with the commandline child process by a pipe. But my worker thread cannot read anything from the pipe (ReadFile always return FALSE) and my worker cannot quit even if the child process quits. So please help me.
Here is my code.
create child process part:
BOOL CMFCApplication3Dlg::execCmd(LPCSTR pCmdArg)
{
//ASSERT(s_hCmdProcess == NULL);
if (s_hCmdProcess != NULL)
{
return FALSE;
}
STARTUPINFO si; // specifies startup parameters for child process.
ZeroMemory(&si, sizeof(STARTUPINFO));
si.dwFlags = STARTF_USESHOWWINDOW | STARTF_USESTDHANDLES; // STARTF_USESTDHANDLES is Required.
si.hStdOutput = s_cmdout_ChildSide; // Requires STARTF_USESTDHANDLES in dwFlags.
si.hStdError = s_cmdout_ChildSide; // Requires STARTF_USESTDHANDLES in dwFlags.
// si.hStdInput remains null.
si.wShowWindow = SW_HIDE; // Prevents cmd window from flashing. Requires STARTF_USESHOWWINDOW in dwFlags.
PROCESS_INFORMATION pi;
ZeroMemory(&pi, sizeof(PROCESS_INFORMATION));
// Create the child process.
BOOL result = CreateProcess(
NULL,
(LPSTR)pCmdArg, // command line
NULL, // process security attributes
NULL, // primary thread security attributes
TRUE, // TRUE=handles are inherited. Required.
CREATE_NEW_CONSOLE, // creation flags
NULL, // use parent's environment
NULL, // use parent's current directory
&si, // __in, STARTUPINFO pointer
&pi); // __out, receives PROCESS_INFORMATION
if (result)
{
s_hCmdProcess = pi.hProcess;
s_hCmdProcessThread = pi.hThread;
}
return result;
}
create pipe part:
LRESULT CMFCApplication3Dlg::createPipe()
{
ASSERT(s_cmdout_ChildSide == NULL && s_cmdout_MainSide == NULL);
if (s_cmdout_ChildSide != NULL || s_cmdout_MainSide != NULL) return FALSE;
SECURITY_ATTRIBUTES saAttr = { sizeof(SECURITY_ATTRIBUTES) };
saAttr.bInheritHandle = TRUE;
saAttr.lpSecurityDescriptor = NULL;
return CreatePipe(&s_cmdout_MainSide, &s_cmdout_ChildSide, &saAttr, 0);
}
the worker thread part:
void CMFCApplication3Dlg::startWorkThread()
{
if (s_hThread == NULL)
{
if (s_hThreadEvent != NULL) CloseHandle(s_hThreadEvent);
s_hThreadEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
//s_hThread = AfxBeginThread(TestThreadProc, this);
s_hThread = AfxBeginThread(ReadCmdOutProc, this);
}
}
UINT ReadCmdOutProc(LPVOID pParam)
{
CWnd *hDlg = (CWnd *)pParam;
//start the child process
BOOL result = CMFCApplication3Dlg::execCmd("ping 127.0.0.1 -n 99");
ASSERT(CMFCApplication3Dlg::s_hCmdProcess != NULL);
for(;;)
{
DWORD dwRetVal_cmd;
//wait for child process quit.
dwRetVal_cmd = WaitForSingleObject(CMFCApplication3Dlg::s_hCmdProcess,100);
DWORD dwRead = 0;
CHAR chBuf[4096];
BOOL readResult = ReadFile(CMFCApplication3Dlg::s_cmdout_MainSide, chBuf, 4096, &dwRead, NULL);
if (readResult)
{
chBuf[dwRead] = 0;
TRACE("read: %s\n",chBuf);
CString* cmdread = new CString(chBuf, dwRead);
//send ui thread update message.
MsgWrapper::Post(hDlg, WM_APP + 11, (WPARAM)cmdread);
}
if (dwRetVal_cmd != WAIT_TIMEOUT)
{
TRACE("thread quit\n");
//release the resource
CMFCApplication3Dlg::releaseCmd();
GetExitCodeThread(CMFCApplication3Dlg::s_hThread, &dwExitCode);
AfxEndThread(dwExitCode);
CMFCApplication3Dlg::s_hThread = NULL;
break;
}
}
}