[yapt]

Bueno, lo ideal sería convertir todas las llamadas a WideChar, pero me ha sido más fácil hacer lo contrario, convertirlas a AnsiChar.

Pruebalo bien, solo está muy ligeramente probado.

Un saludo.

Código Delphi [-]
function TForm1.ejecutarComando (comando : AnsiString) : AnsiString;
var
  Buffer: array[0..4096] of AnsiChar;
  si: STARTUPINFOA;
  sa: SECURITY_ATTRIBUTES;
  sd: SECURITY_DESCRIPTOR;
  pi: PROCESS_INFORMATION;
  newstdin, newstdout, read_stdout, write_stdin: THandle;
  exitcod, bread, avail: Cardinal;
begin
  Result:= '';

  if Win32Platform = VER_PLATFORM_WIN32_NT then
  begin
     InitializeSecurityDescriptor(@sd, SECURITY_DESCRIPTOR_REVISION);
     SetSecurityDescriptorDacl(@sd, true, nil, false);
     sa.lpSecurityDescriptor := @sd;
  end
  else
    sa.lpSecurityDescriptor := nil;

  sa.nLength := sizeof(SECURITY_ATTRIBUTES);
  sa.bInheritHandle := TRUE;
  if CreatePipe(newstdin, write_stdin, @sa, 0) then
  begin
     if CreatePipe(read_stdout, newstdout, @sa, 0) then
     begin
        GetStartupInfoA(si);
        with si do
        begin
          dwFlags := STARTF_USESTDHANDLES or STARTF_USESHOWWINDOW;
          wShowWindow := SW_HIDE;
          hStdOutput := newstdout;
          hStdError  := newstdout;
          hStdInput  := newstdin;
        end;
        Fillchar(Buffer, SizeOf(Buffer), #0);
        GetEnvironmentVariableA(AnsiString('COMSPEC'), @Buffer, SizeOf(Buffer) - 1);
        StrCat(@Buffer,PAnsiChar(' /c ' + comando));
        if CreateProcessA(nil, @Buffer, nil, nil, TRUE, CREATE_NEW_CONSOLE, nil, nil, si, pi) then
        begin
          repeat
             PeekNamedPipe(read_stdout, @Buffer, SizeOf(Buffer) - 1, @bread, @avail, nil);
             if bread > 0 then
             begin
                FillChar(Buffer, SizeOf(Buffer), 0);
                ReadFile(read_stdout, Buffer, bread, bread, nil);
                Result:= Result + AnsiString(PAnsiChar(@Buffer));
             end;
             Application.ProcessMessages;
             GetExitCodeProcess(pi.hProcess, exitcod);
          until (exitcod <> STILL_ACTIVE) and (bread = 0);
        end;
        CloseHandle(read_stdout);
        CloseHandle(newstdout);
     end;
     CloseHandle(newstdin);
     CloseHandle(write_stdin);
  end;
end;