Re: [patch] Allow to link with ncursesw

[Matthias Klose <doko@ubuntu.com>]

On 20.09.2017 20:39, Pedro Alves wrote:
> On 09/13/2017 11:29 AM, Matthias Klose wrote:
>> Triggered by https://launchpad.net/bugs/1275210, to be able to cope with UTF-8
>> characters in gdbtui. Ok for the trunk?
> 
>>
>> Matthias
>>
>> 	* configure.ac: Search ncursesw before ncurses.
>> 	Check ncursesw/ncurses.h before ncurses/ncurses.h.
>> 	* gdb_curses.h: Include <ncursesw/ncurses.h>
>> 	* config.in, configure: Regenerate.
>>
> 
> This sounds a bit scary if readline (or Python?) links with ncurses.
> Looking both upstream readline sources and our local copy in the tree,
> I don't see anything checking for ncursesw.  Looking around for
> ncurses + ncursesw, I found:
> 
>   https://bugs.python.org/issue9408
>   https://bugs.python.org/issue7384
> 
> "Python3 now links _curses.so to ncurses library (bytes version) instead
> of ncursesw library (unicode version) if readline is linked to ncurses."
> ....
> "Thomas Dickey recommended not to load readline+ncurses and ncursesw
> at the same time."
> 
> And:
> 
>  https://bugs.mageia.org/show_bug.cgi?id=2156
>  bugs.debian.org/cgi-bin/bugreport.cgi?bug=602720
> 
> I see you've been involved with all this before.
> 
> Did you reach out to readline/bash, see if they're willing
> to try ncursesw before ncurses too?  Don't we need at least
> a local patch to our local readline copy, to avoid breaking
> those that use it and have it link with ncurses?

afaik, this is only the case if readline is linked with one of the curses
libraries.  However these days everybody seems to have readline linked to just
tinfo, so this shouldn't be an issue?

Python itself doesn't link to a curses library, it uses the only which is used
for readline.

Matthias