http://community.freepascal.org:10000/docs-html/rtl/unix/assignstream.html

A few questions about AssignStream:

1. I can't seem to figure out a way to see if the program I ran actually executed. For example, if I pass in something bogus for the Prog parameter (some filename that doesn't even exist), I still get a PID back. It's just that the PID is in a defunct (zombie) state. I could read the status file in /proc/ for that PID, but that seems rather a waste to do with each program I execute via AssignStream.

2. Is there a way for me to get the exit code of a program executed with AssignStream?

Thanks,

Seth

I actually figured out the answer to both my questions, which I'll post here in case somebody is ever searching these archives and has the same question:

Immediately after calling AssignStream and getting the resultant PID, you can do something like this:

// check to see if the PID has already exited
if (fpWaitPid(pid,pcint(@exitCode),WNOHANG) = pid) then begin
  // a 127 exit code indicates "command not found
  if (wexitstatus(exitCode) = 127) then begin
    raise Exception.Create('PipelineClass.Create: Command not found in PATH');
  end;
end;

Apparently the exit code "127" has a special meaning indicating that the command was not found.

-SG