process output if empty

Question

I am using c# and StandardoutputRedirect to get the output of my process in a string, but the problem that the program sometimes doesn't give any output how ever the process still waiting for an output how can I for example wait for 3 seconds if there is no output continue the program??

Here is my code

Process tcpdump = new Process();
tcpdump.StartInfo.FileName= "/usr/sbin/tcpdump";
tcpdump.StartInfo.CreateNoWindow = true;
tcpdump.StartInfo.Arguments = " -i en1 -c 10 -nn tcp and src host " + ip + " and port " + ports[i];
tcpdump.StartInfo.UseShellExecute = false;
tcpdump.StartInfo.RedirectStandardOutput = true;
tcpdump.Start();
tcpdump.WaitForExit(3000);
string tcpdump_output = tcpdump.StandardOutput.ReadToEnd(); // at this part the programs waits for an output

newfurniturey · Accepted Answer · 2012-08-27 10:09:36Z

3

You have tcpdump.WaitForExit(3000);, which should only have your Process waiting for that long, but you may also want to kill it to move on:

if (!tcpdump.WaitForExit(3000)) {
    tcpdump.Kill();
}

Also, per the documentation, you should call .StandardOutput.ReadToEnd() before calling WaitForExit(), otherwise you can enter a deadlock - which it appears you are. So, try updating your code to:

string tcpdump_output = tcpdump.StandardOutput.ReadToEnd();
if (!tcpdump.WaitForExit(3000)) {
    tcpdump.Kill();
}

edited Aug 27, 2012 at 10:09

answered Aug 27, 2012 at 10:02

newfurniturey

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3 Comments

I.el-sayed Over a year ago

I am sorry but what does this line actually means ?? if the process is not closed after 3000 milli seconds kill it ??

newfurniturey Over a year ago

Correct; WaitForExit(3000) will wait for 3000 milliseconds for the process to exit and if it doesn't exit, it will return false; upon returning false, your application will then kill the process it just started.

I.el-sayed Over a year ago

Nice... Working perfectly dude :) :) Thank you

LueTm · Accepted Answer · 2012-08-27 10:04:17Z

0

Does it work for you then you check

if (tcpdump.EndOfStream)
{
    // ...
}

before reading to the end?

answered Aug 27, 2012 at 10:04

LueTm

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