Capturing console output with Delphi 2010/XE

This new method supersedes the previous one using TDosCommand. It's been tested and it works with Delphi 2010 and Delphi XE, so it's worth to give it a try. It's really easy to use and I'm preparing a little tool with it.

//Anonymous procedure approach by Lars Fosdal
type
    TArg<T> = reference to procedure(const Arg: T);

procedure TForm1.CaptureConsoleOutput(const ACommand, AParameters: String; CallBack: TArg<PAnsiChar>);
const
    CReadBuffer = 2400;
var
    saSecurity: TSecurityAttributes;
    hRead: THandle;
    hWrite: THandle;
    suiStartup: TStartupInfo;
    piProcess: TProcessInformation;
    pBuffer: array [0 .. CReadBuffer] of AnsiChar;
    dBuffer: array [0 .. CReadBuffer] of AnsiChar;
    dRead: DWord;
    dRunning: DWord;
begin
    saSecurity.nLength := SizeOf(TSecurityAttributes);
    saSecurity.bInheritHandle := True;
    saSecurity.lpSecurityDescriptor := nil;

    if CreatePipe(hRead, hWrite, @saSecurity, 0) then
    begin
        FillChar(suiStartup, SizeOf(TStartupInfo), #0);
        suiStartup.cb := SizeOf(TStartupInfo);
        suiStartup.hStdInput := hRead;
        suiStartup.hStdOutput := hWrite;
        suiStartup.hStdError := hWrite;
        suiStartup.dwFlags := STARTF_USESTDHANDLES or STARTF_USESHOWWINDOW;
        suiStartup.wShowWindow := SW_HIDE;

        if CreateProcess(nil, pChar(ACommand + ' ' + AParameters), @saSecurity, @saSecurity, True, NORMAL_PRIORITY_CLASS, nil, nil, suiStartup, piProcess) then
        begin
            repeat
                dRunning := WaitForSingleObject(piProcess.hProcess, 100);
                Application.ProcessMessages();
                repeat
                    dRead := 0;
                    ReadFile(hRead, pBuffer[0], CReadBuffer, dRead, nil);
                    pBuffer[dRead] := #0;

                    //OemToAnsi(pBuffer, pBuffer);
                    //Unicode support by Lars Fosdal
                    OemToCharA(pBuffer, dBuffer);
                    CallBack(dBuffer);
                until (dRead < CReadBuffer);
            until (dRunning <> WAIT_TIMEOUT);
            CloseHandle(piProcess.hProcess);
            CloseHandle(piProcess.hThread);
        end;
        CloseHandle(hRead);
        CloseHandle(hWrite);
    end;
end;

usage:

    CaptureConsoleOutput('java -version', '', 
                procedure(const Line: PAnsiChar) 
                begin
                    Memo1.Lines.Add(String(Line)); 
                end
     );

With all the help I got from Lars, I've released a version of the function for test purposes. You can download the app from here (Thundax Output).

Example:

Updated 13/12/2012:
Check out the latest algorithm in the most updated and revised post:

• Capturing console output with Delphi 2010/XE (revised)

Related links:

• Capture the output from DOS.
• Capture output realtime to memo.
• OemToCharBuff.
• OemToChar.
• OemToAnsi.