CloseHandle HANGS on HANDLE created from CreatePipe

Solution

Add CloseHandle(hChildStd_OUT_Wr) after CreateProcess(...)

Problematic Code

THREAD1:

HANDLE hChildStd_OUT_Rd;
HANDLE hChildStd_OUT_Wr;
CreatePipe(&hChildStd_OUT_Rd, &hChildStd_OUT_Wr, &saAttr, 0);

PROCESS_INFORMATION piProcInfo;
STARTUPINFO siStartInfo;
BOOL bSuccess = FALSE;

// Set up members of the PROCESS_INFORMATION structure.
ZeroMemory( &piProcInfo, sizeof(PROCESS_INFORMATION) );

// Set up members of the STARTUPINFO structure.
// This structure specifies the STDIN and STDOUT handles for redirection.
ZeroMemory( &siStartInfo, sizeof(STARTUPINFO) );
siStartInfo.cb = sizeof(STARTUPINFO);
siStartInfo.hStdError = hChildStd_OUT_Wr;
siStartInfo.hStdOutput = hChildStd_OUT_Wr;
siStartInfo.dwFlags |= STARTF_USESTDHANDLES;
siStartInfo.wShowWindow = true;

// Create the child process.
bSuccess = CreateProcess(NULL,
                         executable,      // command line
                         NULL,      // process security attributes
                         NULL,      // primary thread security attributes
                         TRUE,      // handles are inherited
                         0,      // creation flags
                         NULL,      // use parent's environment
                         currentDir,      // use parent's current directory
                         &siStartInfo,      // STARTUPINFO pointer
                         &piProcInfo);      // receives PROCESS_INFORMATION

if (piProcInfo.hProcess != NULL)
{
   // Waits here until process terminates
   WaitForSingleObject (piProcInfo.hProcess, INFINITE);

  // Process is terminated
  if (hChildStd_OUT_Rd != NULL)
  {
       CloseHandle(hChildStd_OUT_Rd); <= HANGS HERE!!!
  }

  CloseHandle(piProcInfo.hProces);
  
  if (piProcInfo.hThread != NULL)
  {
      CloseHandle(piProcInfo.hThread);
  }
}

THREAD2:

DWORD dwRead, dwWritten;
CHAR chBuf[BUFSIZE];
BOOL bSuccess = FALSE;
HANDLE hParentStdOut = GetStdHandle(STD_OUTPUT_HANDLE);

int threadId = (int)QThread::currentThreadId();
qDebug() << "ReadFromPipe from threadId:" << threadId;

if (fileStdout_ == NULL)
{
   qDebug() << "fileStdout_ is NULL, aborting";
   return;
}

for (;; )
{
   bSuccess = ReadFile( hChildStd_OUT_Rd_, chBuf, BUFSIZE, &dwRead, NULL);
   
   if( !bSuccess || dwRead == 0 )
   {
      qDebug() << "qDebug() Failure reading hChildStd_OUT_Rd_";
      break;
   }

   fwrite(chBuf, dwRead, 1, fileStdout_);
   fflush(fileStdout_);

   if (!bSuccess ) break;
}

qDebug() << "qDebug() hChildStd_OUT_Rd_ TERMINATED taskId:" << haiProcess_->taskId_;

if (hParentStdOut != INVALID_HANDLE_VALUE)
SetStdHandle(STD_OUTPUT_HANDLE, hParentStdOut);

fclose(fileStdout_);
fileStdout_ = NULL;

qDebug() << "qDebug() [ReadFromPipe] TERMINATED taskId:" << haiProcess_->taskId_;

Corrected Code

      // Close inheritable copies of the handles you do not want to be

      // inherited.

      if (!CloseHandle(hOutputReadTmp)) DisplayError("CloseHandle");

      if (!CloseHandle(hInputWriteTmp)) DisplayError("CloseHandle");