Hi,

I am having some problems writing to the InputStream of a Tprocess object. Below is the source code. I am testing this on windows. When stepping through the code I get INVALID_HANDLE as return value of the FileWrite in THandleStream.Write.
I think there is a bug somewhere in the Tprocess code for win32, but before digging deeper I would like to know if anybody has succesfully used Tprocess like this on win32 platform.

Regards,
Vincent.

The following procedure is from the parent application.
procedure DoIt;
var
  LogProcess: TProcess;
  procedure WriteLine(const s: string);
  var
    buffer: string;
  begin
    buffer := s + LineEnding;
    LogProcess.Input.Write(buffer, Length(buffer));
  end;
begin
  LogProcess := TProcess.Create(nil);
  LogProcess.Options := [poUsePipes];
  LogProcess.CommandLine := 'logger.exe';
  LogProcess.Execute;
  WriteLine('test');
  WriteLine('q');
  LogProcess.WaitOnExit;
end;

The logger application is simply reads line from stdin and writes temp to a file, until the line 'q' is received. The source is this: program logger;

{$mode objfpc}{$H+}
uses
  Classes;
var
  logfile: text;
  line: string;
procedure init;
begin
  assignfile(logfile, 'd:\troep\log.txt');
  rewrite(logfile);
  writeln(logfile, 'Started logging');
  closefile(logfile);
end;
procedure AppendText(line: string);
begin
  append(logfile);
  writeln(logfile, line);
  closefile(logfile);
end;
begin
  repeat
    readln(line);
    appendText(line);
  until line='q';
end.

Eh ?? This should be

    LogProcess.Input.Write(buffer[1], Length(buffer));

Otherwise you will get some VERY strange things.

Secondly, in your logger app, you forget to do init, to open the file.

Michael.

Michael,

Thanks for your comments.

<source snipped>

Thanks for the hint. I made the changes, but it doesn't solve the problem though.

Secondly, in your logger app, you forget to do init, to open the file.

Sorry, this was a cut and past error.

To prevent this I add the source in a zip.

If I do the following in dos-box, a log.txt is created: type q.txt | logger.exe
So I conclude logger is working as expected.

but
running testprocess.exe
doesn't return, and only the header of the log file is written, so the logger hasn't received any info from testprocess.exe.

Vincent.

I will test tomorrow at work (don't have winblows currently here at home)

Michael.

That is what I also thought, until I found out that
- The log file didn't contain the contents of q.txt
- I was actually executing the cygwin logger program.

It works fine here if I change commandline to '.\logger.exe'

Michael.

I have been trying to find out, why it works on your computer and not on mine.

It turns out, that it fails with fpc 1.0.11 (5-3-2004) and works with fpc 1.9.3 (10-3-2004). Windows and Linux versions behave the same way (failure with fpc 1.0.11 and success with fpc 1.9.3).

In both versions I am using process.pp version 1.19.

Do you have a clue, what might cause these different behaviour?

Compiling with 1.9.3 is not a option at the moment, because I need to be able to use a debugger and debug info is still not working right.

TIA,
Vincent.