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Date: Mon, 9 Jan 2012 11:12:56 -0500
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Subject: Re: Does Cygwin Terminal queue output to stdout?
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>> When I run tshark or windump in a cmd.exe window (e.g. "tshark -i1
>> -n") I see immediate output of network traffic seen by my network
>> interface and continues to stream live network traffic information.
>>
>> When I run either program in Cygwin Terminal, there is about a 20
>> second delay before I see any output.  At which time it immediately
>> dumps the previous 20 seconds of "queued up" output and hangs again
>> for 15-20 seconds, followed by another dump of "queued up" output,
>> etc...
>>
>> Is there some way I can have Cygwin Terminal stream the data like cmd.exe does?
>
> From the point of view of these programs, mintty is a pipe. When a
> program thinks it's writing to a display (a tty), it typically flushes
> the output after every line. But when a program thinks the user won't
> see its output, a program typically flushes its buffers less often
> because writing in larger chunks is more efficient. You need to
> convince these non-Cygwin programs to not buffer their output. Have
> you tried the conin utility?
>
> https://code.google.com/p/mintty/source/browse/utils/conin.c
>

In case anyone is searching this in the future, windump and tshark
both have a command line switch of "-l" that flushes standard output
after each packet.  Using this resolves the issue.

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