[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]
Re: lib/56224: libcurses: adding character to last line of non-scrolling window wraps instead of
The following reply was made to PR lib/56224; it has been noted by GNATS.
From: Brett Lymn <blymn%internode.on.net@localhost>
Cc: blymn%netbsd.org@localhost, gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost,
Subject: Re: lib/56224: libcurses: adding character to last line of
non-scrolling window wraps instead of
Date: Thu, 10 Jun 2021 16:01:14 +0930
On Thu, Jun 10, 2021 at 03:55:02AM +0000, Michael Forney wrote:
> Thanks for the patch, I can confirm that this does solve the issue
> for the application in question (catgirl).
Excellent, that is a good start.
> 1. It seems that now the string is truncated by one extra character
> (the last column is empty). Since this last character doesn't extend
> beyond the end of the line, my expectation is that it should not
> be truncated. And indeed, this is how it behaves in ncurses.
OK, I will fix that - my checks must be off by one.
> 2. I was thinking that this needed to be fixed in _cursesi_addwchar,
> not _cursesi_addwbytes. Otherwise, addwstr and addch at the last
> column still wrap to column 0 (though, addwstr already truncates
> since it returns on the first ERR, whereas _curses_waddbytes ignores
> all errors except for the last character).
No, _cursesi_addwchar is used by other routines that really should be
inheriting the same behaviour, rather than fix each one individually I
went for fixing it in the common routine so they all behaved the same.
I think addwstr is the outlier in this instance. I will look at fixing
> 3. This seems incorrect to me:
Yes, it is. My bad. I will rework that. That probable explains why
the wide char version of the slk test failed after my updates.
> Below is an alternative fix I've been testing that seems to solve
> these problems. The first thing it does is make _cursesi_waddbytes
> break from the loop and return ERR when any of the _cursesi_addwchar
> calls returns ERR (not just the last one). This is consistent with
> waddnwstr. The second thing it does is delay wrapping the cursor x
> position back to zero until after we return ERR if scrolling is not
I may have read the SUSv2 section on the scrolling behaviour incorrectly
but my interpretation is that trying to add a string at the bottom of
the screen that would cause a scroll when scrollok is false should
result in a silent truncation not ERR which is why I did what I did.
The effect of my change is a slk routine that used to strangely return
ERR no longer does so... I would like to keep that behaviour :)
The patch you have proposed does not look right, with your fix you will
have possibly not reset x to 0 but ISPASTEOL will be unset so the unset
of the ISPASTEOL flag needs to be moved too which does make some sense
to have that after a possible error return. I will have a look at doing
Sent from my NetBSD device.
"We are were wolves",
"You mean werewolves?",
"No we were wolves, now we are something else entirely",
Main Index |
Thread Index |