Re: lib/53642: noecho(3) in curses(3) does not disable echoing

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

The following reply was made to PR lib/53642; it has been noted by GNATS.

From: Valery Ushakov <uwe%stderr.spb.ru@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: lib-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
	netbsd-bugs%netbsd.org@localhost
Subject: Re: lib/53642: noecho(3) in curses(3) does not disable echoing
Date: Sat, 29 Sep 2018 20:15:38 +0300

 On Sat, Sep 29, 2018 at 14:40:00 +0000, n54%gmx.com@localhost wrote:
 
 > In the NetBSD version of noecho(3) there is still performed echoing
 > of user entered input onto the screen.
 >
 > A work around to disable echoing bytes is to combine noecho(3) with
 > cbreak(3).
 
 This is not a workaroud.
 
 The same quoted SUS document later says:
 
   Initialised Curses Environment
 
   [...] To get character-at-a-time input without echoing (most
   interactive, screen-oriented programs want this), the following
   sequence should be used:
 
       initscr()
       cbreak()
       noecho()
 
 SCO curses docs ("SCO UNIX Development System.  User Interfaces
 Guide."  Date: 10 December 1991.  Document Version: 3.2.4D) say in
 "Controlling the terminal" on p.42
 
   Do not use the combination of nocbreak() and echo(). If you use it
   in a program and also use getch(), the program will go in and out of
   cbreak() mode to get each character. Depending on the state of the
   tty driver when each character is typed, the program may produce
   undesirable output.
 
 There seems to be a copy available from
 
 https://computerarchive.org/files/comp/manuals/unix/sco_unix_dev_sys_user_interfaces_guide_324d.pdf
 
 -uwe