Copying maintainer.
Alberto Garcia <be...@igalia.com> writes:
> We have this code in qjson.c to produce JSON from a QFloat:
>
> QFloat *val = qobject_to_qfloat(obj);
> char buffer[1024];
> int len;
>
> len = snprintf(buffer, sizeof(buffer), "%f", qfloat_get_double(val));
> while (len > 0 && buffer[len - 1] == '0') {
> len--;
> }
>
>
> The problem here is that the output of snprintf() is locale-dependent,
> so depending on the locale we might get a ',' as decimal separator.
> That's not allowed by JSON and it actually breaks scripts/qmp/qmp.
>
> This seems to happen because of GTK+ calling setlocale(). The easiest
> solution is probably to call setlocale(LC_NUMERIC, "C") before
> snprintf() (or at start-up ui/gtk.c), but opinions are welcome.
A library calling setlocale() is a big no-no in my book.
Overriding LC_NUMERIC as you propose should fix this particular bug.
However, exposing unprepared code to locale is not a good idea for other
categories as well. LC_COLLATE and LC_CTYPE are even sneakier sources
of bugs in my experience. I'd really, really prefer to stay in the "C"
locale *completely*.
