Re: System.Diagnostics.Process: Asynchronous reading console output causes problems

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Hi Sun,

thanks, that synchronous version seems to be working so far.

One more question:
I also would like to feed the input to the app via stdin. Unfortunately this has to be terminated by Ctrl+Z or Ctrl+D. How can I send this to the console? I already tried
p.StandardInput.Write("\u001A")
without success.

Many thanks,
Thorsten

""Hongye Sun [MSFT]"" <hongyes@xxxxxxxxxxxxxxxxxxxx> wrote in message news:RXRg2OfhJHA.3596@xxxxxxxxxxxxxxxxxxxxxxxxx
Thanks for Pete's insightful analysis.

Hi Thorsten,

Thanks for your post. My name is Hongye Sun [MSFT] and it is my pleasure to
work with you on this issue.

I want to complement Pete with the following comments:

One possible method in synchronize mode:
The synchronous mode buffer cannot be changed. It is hardcoded as 0x1000.
In synchronous mode, when application running, the child process will first
write to the buffer until it exceeds the buffer size and then it will wait
for the parent process read the buffer. It can continue running after the
buffer is readed. If the parent process waits for child process to run one
second, both child and parent processs will stop running because the child
process is waiting for buffer and the parent process is waiting for child
process. The solution to break this waiting is let parent process to read
the buffer. In order to explain myself well, here is a sample code (I do
not know F# also, so I write it in C#):
-------------------------------------------------
ProcessStartInfo psi = new ProcessStartInfo(@"<Console App
Path>");
psi.CreateNoWindow = true;
psi.RedirectStandardError = true;
psi.RedirectStandardOutput = true;
psi.UseShellExecute = false;

Process p = Process.Start(psi);

Stopwatch s = new Stopwatch();
s.Start();

while (s.ElapsedMilliseconds < 1000)
{
result += p.StandardOutput.ReadLine() + "\r\n";
}
s.Stop();

p.Close();
Console.Write(result);
Console.Read();
-------------------------------------------------
The sample read the buffer line by line untill the time is greater than one
second. This works fine in our lab's environment.

For the asynchronous mode, I rewrite the code as below. It works perfect to
me. Please try the following code first. If it does not work, please show
us source code of the target console application (eprover.exe). You can
also send it to my mail box hongyes@xxxxxxxxxxxxxxxxxxxx, remove 'online.'
-------------------------------------------------
DataReceivedEventHandler dataRec = new
DataReceivedEventHandler(delegate(object sender, DataReceivedEventArgs e)
{
lock (result)
{
result += (e.Data + "\r\n");
}
});

ProcessStartInfo psi = new ProcessStartInfo(@"<Console App
Path>");
psi.CreateNoWindow = true;
psi.RedirectStandardError = true;
psi.RedirectStandardOutput = true;
psi.UseShellExecute = false;

Process p = Process.Start(psi);
p.OutputDataReceived += dataRec;

lock (result) { result = ""; }
p.BeginOutputReadLine();

if (!p.WaitForExit(1000))
{
p.Kill();
p.CancelOutputRead();
p.OutputDataReceived -= dataRec;
p.Close();
}
else
{
p.CancelOutputRead();
p.OutputDataReceived -= dataRec;
lock (result) { result = p.StandardError.ReadToEnd() +
result; }
}
Console.Write(result);
Console.Read();
-------------------------------------------------

Please feel free to contact me if you have any question. I am glad to help.

Have a nice day.

Regards,
Hongye Sun (hongyes@xxxxxxxxxxxxxxxxxxxx, remove 'online.')
Microsoft Online Community Support

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