Re: ncurses-5.7-20090530.patch.gz

[Clemens Ladisch]

Thomas Dickey wrote:
> On Wed, 3 Jun 2009, Clemens Ladisch wrote:
>> I don't quite understand your last sentence.  As far as I understand
>> the curses specification, ncurses should _never_ stop using the legacy
>> encoding because any locale could use an encoding that has non-printable
>> characters above 127.  For example, UTF-8 uses the bytes 128..253 for
>> multi-byte sequences, so none of these are printable.
> 
> Not exactly.  If the locale is unset, technically only POSIX (0-127) is
> recommended.  However, since 1997 (before locale support on Linux was
> anything but vaporware), ncurses has interpreted that case as ISO-8859-1
> (hence "legacy").

So this is why unctrl() calls iswprint()?

> If the locale is set, ncurses follows that (or should - barring bug
> reports).

Well, this is the point of my bug report; unctrl() _always_ calls both
isprint() and iswprint(), so it uses the union of the printable
characters of both the current locale and of ISO 8859-1.

It should avoid calling iswprint() once another locale has been set, but
I don't see how this could be detected: the return value of setlocale()
is not portable, and ASCII and UTF-8 are indistinguishable as far as
isprint() is concerned.


Best regards,
Clemens