Re: wchgat strips A_ALTCHARSET attrib; should it?

[Thomas Dickey]

On Fri, Nov 06, 2020 at 07:24:12PM -0600, Bryan Christ wrote:
> It's been this way for a long time.  I've worked around it by checking for
> the flag, saving it, and then adding it back after the call.

There's nothing explicit in X/Open which would require that the alternate
character set be trimmed:

https://pubs.opengroup.org/onlinepubs/7908799/xcurses/chgat.html

however, following a few links takes me here:

https://pubs.opengroup.org/onlinepubs/7908799/xcurses/attroff.html

        It is unspecified whether these functions can be used to manipulate
        attributes other than A_BLINK, A_BOLD, A_DIM, A_REVERSE, A_STANDOUT and
        A_UNDERLINE. 

which I seem to recall having read at some point.

> On Fri, Nov 6, 2020, 19:00 Bill Gray <pluto@projectpluto.com> wrote:
> 
> >     This "bug" (if it is one) cropped up in PDCursesMod,
> > which provides screen shots that should make the sort of
> > misbehavior obvious :
> >
> > https://github.com/Bill-Gray/PDCursesMod/issues/192
> >
> >     The same thing happens in ncurses.  As you can see in the
> > discussion at the above link,  we're unclear if this is the
> > specified behavior,  or if it's a for-real bug.  It is
> > certainly undesirable behavior,  but I don't want to "fix"
> > it in PDCursesMod if it's supposed to do that.
> >
> >     I've posted a minimal example showing the bug at
> >
> > https://www.projectpluto.com/temp/box.c
> >
> >     Any opinion?

fwiw, Solaris xpg4 (X/Open) curses behaves the same as ncurses in this case.

To test that, I replaced the getch loop on KEY_RESIZE with just getch,
and set TERM=vt100 -- attached

AIX and HPUX generally behave the same as the xpg4 curses.

(NetBSD curses also matches ncurses here, but that's proven to be a wothless
comparison in either case).

-- 
Thomas E. Dickey <dickey@invisible-island.net>
https://invisible-island.net
ftp://ftp.invisible-island.net

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