Re: cbreak+echo+nl: carriage return but no newline

[G. Branden Robinson]

Hi Thomas,

At 2024-03-12T18:11:40-0400, Thomas Dickey wrote:
> ...that "echoed" should remind the reader that text gets to the screen
> by "addch" or something equivalent.

That's why part of my pending revision said this...

getch(3x):
     •   curses writes any other ch to the window, as with
         wechochar(3X).

It seemed useful to call out wechochar() specifically since it's getting
called and doing a refresh() without my involvement.

        while (TRUE) {
                ch = getch();
                (void) napms(50);
        }

With a preceding cbreak() and echo(), this loop is a perfectly useful,
if dumb, typewriter.

> There probably are similar cases in other manpages...

Well, that's what ya have me around for.

> either way, the test program returns ^J from getch for me for either
> key...

Same here; my example was cut down from a slightly more elaborate one
that reported the keycode.  I get back code 10 reliably no matter
whether I press Return, ^M, or ^J.  But only ^J echoes as a line feed.

I guess the thing I missed that is that the semantics of the carriage
return keystroke were honored before the translation of its keycode
value.  I think I may have assumed that nl() and nonl() were
manipulating the terminal state in the same way that "stty -ocrnl" does.
(Or do I mean "stty -icrnl"?)

So all nl() and nonl() do is convert the keycode reported by wgetch()?

...huh, wow, yes, it seems so.

Reading through the layers of preprocessor macros and OS/2 support,
that's what I'm seeing in ncurses/base/lib_nl.c:54-88 and
ncurses/base/lib_getch.c:650-651.

What is this feature _for_?  Disparate terminal behavior in the '80s,
similar to the "backspace/delete is ^H!  no, it's ^?" we endured much
more recently?

BTW some of my pending changes are not small.

$ COLUMNS=72 git diff --stat
 man/curs_add_wch.3x   |  26 +-
 man/curs_addch.3x     | 431 +++++++++++++++---------
 man/curs_get_wch.3x   |  35 +-
 man/curs_getch.3x     | 768 +++++++++++++++++++++++++++---------------
 man/man_db.renames.in |   7 +
 5 files changed, 820 insertions(+), 447 deletions(-)

The _wch ones will probably get bigger (synchronization).

Regards,
Branden

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