Capture the Output of a DOS application

unit uDOSOutput;

interface

uses Windows;

function ExecuteCommand(CommandLine:string):string;

var

  mCommand: string;

  mOutputs: string;

implementation

function ExecuteCommand(CommandLine:string):string;

var

  PROC:       TProcessInformation;

  Ret:        LongBool;

  START:      TStartupInfo;

  SA:         TSecurityAttributes;

  hReadPipe:  THandle;

  hWritePipe: THandle;

  dBytesRead: DWORD;

  sBuff:      array[0..255] of Char;

begin

  if Length(CommandLine) > 0 then

    mCommand := CommandLine;

  if Length(mCommand) = 0 then

  begin

    MessageBox(0, PChar('Command Line empty.'), PChar('Error'), MB_ICONEXCLAMATION);

    Exit;

  end;

  SA.nLength := SizeOf(TSecurityAttributes);

  SA.bInheritHandle := TRUE;

  SA.lpSecurityDescriptor := nil;

  Ret := CreatePipe(hReadPipe, hWritePipe, @SA, 0);

  if not Ret then

  begin

    MessageBox(0, PChar('CreatePipe() failed.'), PChar('Error'), MB_ICONEXCLAMATION);

    Exit;

  end;

  FillChar(START ,Sizeof(TStartupInfo), #0);

  START.cb := SizeOf(TStartupInfo);

  START.dwFlags := STARTF_USESTDHANDLES or STARTF_USESHOWWINDOW;

  START.hStdOutput := hWritePipe;

  START.hStdError := hWritePipe;

  Ret := CreateProcess(nil, PChar(mCommand), @SA, @SA, TRUE, NORMAL_PRIORITY_CLASS, nil, nil, START, PROC);

  if Ret <> TRUE then

  begin

    MessageBox(0, PChar('File or command not found.'), PChar('Error'), MB_ICONEXCLAMATION);

    Exit;

  end;

  Ret := CloseHandle(hWritePipe);

  mOutputs := '';

  repeat

    Ret := ReadFile(hReadPipe, sBuff, 255, dBytesRead, nil);

    mOutputs := mOutputs + Copy(sBuff, 1, dBytesRead);

  until Ret = FALSE;

  Ret := CloseHandle(PROC.hProcess);

  Ret := CloseHandle(PROC.hThread);

  Ret := CloseHandle(hReadPipe);

  ExecuteCommand := mOutputs

end;

end.

ShowMessage(ExecuteCommand('netstat'));