[Mono-devel-list] System.Diagnostics.Process redirection

[John Bailo]

On Sunday 03 July 2005 06:10, Colin JN Breame wrote:
> Hello,
>
> Below is a program that on my system replicates an unexpected exit by the
> mono runtime.
>
> The lines of interest are:
>
> 	stdout.WriteLine("1");
> 	p.StandardInput.WriteLine("hello world!");
> 	stdout.WriteLine("2");
>
> As the program runs, it prints '1' but exit before '2' is printed
>

1. Have you tried adding a catch so you can see any errors that might be 
thrown?   You have that code nested in a try -- but no cache.

2. Have you stepped it through monodevelop?

3. I know from Windows .NET that the methods for monitoring the state, and 
completion of a Process is somewhat ill-defined.   Yes, there are several 
sample code examples but some say different things.   For a project I did 
that send an lpr command, I ended up doing two things.

Set a new Process equal to the actual process and monitor that as a kind of 
"handle".   Two, put in a Thread.Sleep to give  process a chance to "clean 
up".   There seems to be some long disconnect between when the process 
'stops' and when it 'really stops'.

At least that has been my experience w/Windows.NET


> .  
>
> Any ideas what might be going on here?  Could this be SIGPIPE related?
>
>  -- Colin
>
> ps. mono 1.1.8.1
>
>
>
> using System;
> using System.IO;
> using System.Diagnostics;
>
> public class main_t {
>
>         public static void Main() {
>                 while (true) {
>                         run();
>                 }
>         }
>
>         public static void run() {
>                 Process p = null;
>
>                 try {
>                         p = new Process();
>
>                         string pipe = "echo hello";
>
>                         int i = pipe.IndexOf(' ');
>                         if (i == -1) {
>                                 p.StartInfo.FileName = pipe;
>                         } else {
>                                 p.StartInfo.FileName = pipe.Substring(0,
> i); p.StartInfo.Arguments = pipe.Substring(i+1, pipe.Length-i-1);
>                         }
>
>                         p.StartInfo.UseShellExecute = false;
>                         p.StartInfo.RedirectStandardInput = true;
>                         try {
>                                 p.Start();
>                         } catch (Exception e) {
>                                 Console.Error.WriteLine("could not execute:
> {0}", pipe);
>                                 goto init_error;
>                         }
>
>                         TextWriter stdout = Console.Out;
>                         Console.SetOut(p.StandardInput);
>                         stdout.WriteLine("1");
>                         p.StandardInput.WriteLine("hello world!");
>                         stdout.WriteLine("2");
>                         Console.SetOut(stdout);
>
>                         p.StandardInput.Close();
>
>                         if (p != null) {
>                                 p.WaitForExit();
>                         }
>
>                 } finally {
>                         if (p != null) p.Close();
>                 }
>         init_error:;
>         }
> }
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