Re: On non-Windows, hard depend on uselocale(3)

On Mon, Nov 20, 2023 at 11:36 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Thomas Munro <thomas(dot)munro(at)gmail(dot)com> writes:
> > BTW is this comment in snprintf.c true?
>
> > * 1. No locale support: the radix character is always '.' and the '
> > * (single quote) format flag is ignored.
>
> > It is in the backend but only because we nail down LC_NUMERIC early
> > on, not because of any property of snprintf.c, no?
>
> Hmm, the second part of it is true. But given that we punt float
> formatting to libc, I think you are right that the first part
> depends on LC_NUMERIC being frozen.

If we are sure that we'll *never* want locale-aware printf-family
functions (ie we *always* want "C" locale), then in the thought
experiment above where I suggested we supply replacement _l()
functions, we could just skip that for the printf family, but make
that above comment actually true. Perhaps with Ryu, but otherwise by
punting to libc _l() or uselocale() save/restore.