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Wireshark-users: Re: [Wireshark-users] tshark buffered packet dissection -- no realtime output?

From: Guy Harris <guy@xxxxxxxxxxxx>
Date: Sat, 13 Jan 2018 18:40:04 -0800
On Jan 13, 2018, at 9:19 AM, Eldon <wireshark-users@xxxxxxxxxxxx> wrote:

> I realize this is a longshot, but my mind immediately went to pipe
> buffering as well, and a comment on stackoverflow[1] seems to indicate
> that there are some situations where stdbuf -o0 will not work due to a
> variety of security measures or alternate configs/stdlibs. Since tshark
> might have some certain capabilities flags set, I just thought it might
> be worth checking!

Whatever capability flags are set on tshark would matter only if he's using stdbuf on tshark; if he's using it on curl, the issue would be whether *curl*, not *tshark*, prevented dynamic library injection.

And the actual issue is in the low-level code (*very* low-level code) in libwiretap that TShark uses to read the capture; that code isn't using the "standard I/O" libraries, so stdbuf won't affect it.  Even if curl *isn't* buffering its output, TShark, in effect, reads it as if it were buffered.