Subject: Re: bug#5359: 23.1.91; CRITICAL BUG: process-send-region hangs ntEmacs if region >64K

From: Eli Zaretskii <[email-masked]>
Date: Thu, 07 Jul 2016 05:42:28 +0300

> From: [email-masked]
> Date: Wed, 06 Jul 2016 19:49:26 -0400
> Cc: [email-masked]
> 
> I tried from emacs -Q
> 
> (dotimes (i (/ (* 65 1024) 80))
>   (insert (make-string 80 ?x) ?\n))
> 
> ;; I have cat.exe in PATH due to running from MSYS.
> (progn (setq process (start-process "test" "tempbuff" "cat"))
>        (process-send-region process (point-min) (point-max)))
> 
> Didn't hang.  Maybe it's fixed?

Most probably.  This area saw quite some improvement in Emacs 24.5.