[Bug preprocessor/92987] -finput-charset is only usable with encodings that are supersets of ASCII

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92987

--- Comment #3 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
On Wed, 18 Dec 2019, lhyatt at gmail dot com wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92987
> 
> --- Comment #2 from Lewis Hyatt <lhyatt at gmail dot com> ---
> (In reply to joseph@codesourcery.com from comment #1)
> > I think -finput-charset may only be usable for character sets that are 
> > valid locale character sets (we don't implement the POSIX rule of 
> > interpreting source files in the locale encoding), which does mean 
> > supersets of ASCII.  And headers provided by one project for use by 
> > another indeed do practically need to be ASCII to be maximally portable.
> 
> OK thanks. I guess I am confused why charset.c implements conversion functions
> for UTF-16 and UTF-32, that can never actually be used without an error, but
> sounds like this use case is not important in any case?

I'd expect that's for use with -fwide-exec-charset.