Maybe I'm just dumb, but I cannot figure out why this isn't working.

I wanted to write a simple program which uses TProcess to send input to festival (the text-to-speech engine). On the command line I can do something simple like this:
echo hello | /usr/bin/festival --tts --pipe
and festival will say "hello". Pretty easy...

So why won't this work?

program talkie;
{$mode objfpc}{$H+}
uses
  Classes, SysUtils, Process;
var
  festival : TProcess;
  line : string;
begin
  try
    festival := TProcess.Create(nil);
    try
      festival.Options := [poUsePipes, poStderrToOutput, poNoConsole,
poDefaultErrorMode];
      festival.CommandLine := '/usr/bin/festival --pipe --tts';
      line := 'hello'
      festival.Execute;
      festival.Input.WriteBuffer(line[1], length(line));
    finally
      festival.Terminate(0);
      FreeAndNil(festival);
    end;
  except
    on E : Exception do begin
      writeln('Exception: ' + E.Message);
    end;
  end;
end.

I've googled TProcess for about 2 hours and I'm not seeing what I'm missing. Can someone smarter than me please illuminate me?

Thanks,

Seth

Maybe:
        line := 'hello' + LineEnding;

Vincent

Looks to me like you are terminating the process as soon as you write to the pipe. Don't you have to give it time to breathe?

Okay, I figured it out...

Turns out I was using festival wrong, though I'm still not sure how. It wasn't a problem with how I was using TProcess.

If I run festival like this (not using --tts mode)

    FestivalProc.CommandLine := '/usr/bin/festival --pipe';

And pass "SayText" commands like this, rather than just passing it the text I want read:

    line := '(SayText "hello")';
    FestivalProc.Input.WriteBuffer(line[1], length(line));

It works fine.

Thanks for your help!

-SG