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copied!<p>As far I understand, you want to preserve the order of stdout/stderr messages. I don't see any DECENT way to do this with C# managed Process(reflection - yes, nasty subclassing hacking - yes). It seems that it's pretty much hardcoded. </p> <p>This functionality does not depend on threads themselves. If you want to keep the order, <code>STDOUT</code> and <code>STDERROR</code> have to use same handle(buffer). If they use the same buffer, it's going to be synchronized.</p> <p>Here is a snippet from Process.cs:</p> <pre><code> if (startInfo.RedirectStandardOutput) { CreatePipe(out standardOutputReadPipeHandle, out startupInfo.hStdOutput, false); } else { startupInfo.hStdOutput = new SafeFileHandle( NativeMethods.GetStdHandle( NativeMethods.STD_OUTPUT_HANDLE), false); } if (startInfo.RedirectStandardError) { CreatePipe(out standardErrorReadPipeHandle, out startupInfo.hStdError, false); } else { startupInfo.hStdError = new SafeFileHandle( NativeMethods.GetStdHandle( NativeMethods.STD_ERROR_HANDLE), false); } </code></pre> <p>as you can see, there are gonna be two buffers, and if we have two buffers, we have already lost the order information.</p> <p>Basically, you need to create your own Process() class that can handle this case. Sad? Yes. The good news is that it's not hard, it seems pretty simple. Here is a code taken from StackOverflow, not C# but enough to understand the algorithm:</p> <pre><code>function StartProcessWithRedirectedOutput(const ACommandLine: string; const AOutputFile: string; AShowWindow: boolean = True; AWaitForFinish: boolean = False): Integer; var CommandLine: string; StartupInfo: TStartupInfo; ProcessInformation: TProcessInformation; StdOutFileHandle: THandle; begin Result := 0; StdOutFileHandle := CreateFile(PChar(AOutputFile), GENERIC_WRITE, FILE_SHARE_READ, nil, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0); Win32Check(StdOutFileHandle <> INVALID_HANDLE_VALUE); try Win32Check(SetHandleInformation(StdOutFileHandle, HANDLE_FLAG_INHERIT, 1)); FillChar(StartupInfo, SizeOf(TStartupInfo), 0); FillChar(ProcessInformation, SizeOf(TProcessInformation), 0); StartupInfo.cb := SizeOf(TStartupInfo); StartupInfo.dwFlags := StartupInfo.dwFlags or STARTF_USESTDHANDLES; StartupInfo.hStdInput := GetStdHandle(STD_INPUT_HANDLE); StartupInfo.hStdOutput := StdOutFileHandle; StartupInfo.hStdError := StdOutFileHandle; if not(AShowWindow) then begin StartupInfo.dwFlags := StartupInfo.dwFlags or STARTF_USESHOWWINDOW; StartupInfo.wShowWindow := SW_HIDE; end; CommandLine := ACommandLine; UniqueString(CommandLine); Win32Check(CreateProcess(nil, PChar(CommandLine), nil, nil, True, CREATE_NEW_PROCESS_GROUP + NORMAL_PRIORITY_CLASS, nil, nil, StartupInfo, ProcessInformation)); try Result := ProcessInformation.dwProcessId; if AWaitForFinish then WaitForSingleObject(ProcessInformation.hProcess, INFINITE); finally CloseHandle(ProcessInformation.hProcess); CloseHandle(ProcessInformation.hThread); end; finally CloseHandle(StdOutFileHandle); end; end; </code></pre> <p>Source: <a href="https://stackoverflow.com/questions/19211958/how-to-redirect-large-amount-of-output-from-command-executed-by-createprocess">How to redirect large amount of output from command executed by CreateProcess?</a></p> <p>Instead of file, you want to use CreatePipe. From pipe, you can read asynchronously like so:</p> <pre><code>standardOutput = new StreamReader(new FileStream( standardOutputReadPipeHandle, FileAccess.Read, 4096, false), enc, true, 4096); </code></pre> <p>and BeginReadOutput()</p> <pre><code> if (output == null) { Stream s = standardOutput.BaseStream; output = new AsyncStreamReader(this, s, new UserCallBack(this.OutputReadNotifyUser), standardOutput.CurrentEncoding); } output.BeginReadLine(); </code></pre>

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