DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 447BF3858402
Date: Tue, 5 Oct 2021 06:55:48 +0900
To: cygwin@cygwin.com
Subject: Re: is there a limit on how many mintty terminals can be open at once?
Message-Id: <20211005065548.2c02fff49d281a3166656e1d@nifty.ne.jp>
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From: Takashi Yano via Cygwin <cygwin@cygwin.com>
Reply-To: Takashi Yano <takashi.yano@nifty.ne.jp>
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On Mon, 4 Oct 2021 22:51:55 +0300
Andrey Repin wrote:
> Greetings, Brian Inglis!
> 
> > On 2021-10-03 13:58, Takashi Yano via Cygwin wrote:
> >> On Sun, 3 Oct 2021 12:25:15 -0400
> >> "Jason Pyeron" wrote:
> >>> I got the "Error: Could not fork child process: There are no
> >>> available terminals (-1)" error.
> >>> Closing N minty terminals allowed me to open exactly N more.
> >>> My google fu is poor, since I cannot seem to find relevant pages.
> >>> What is the limit?
> 
> >> In current cygwin, maximum number of pty is 128.
> >> It is hard coded and not configurable by user.
> >> https://cygwin.com/git/?p=newlib-cygwin.git;a=blob;f=winsup/cygwin/tty.h#l15
> 
> > Why would you want and how could you use 128 local terminal windows on 
> > one system, where could you put them, and be able to read them, unless 
> > you are building some kind of control centre, and then wouldn't GUI 
> > processes forked under a windows system be more useful?
> 
> Won't SSH sessions allocate pty's ?

Incoming SSH session consumes pty. Therefore, up to 128 users (or sessions)
can login to the cygwin SSH server simultaneously. This is much less than
modern Linux (e.g. 4096 on debian).

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>

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