Re: [Caml-list] string_of_float -> float_of_string locale dependency bug

[Yamagata Yoriyuki <yoriyuki@mbg.ocn.ne.jp>]

From: Xavier Leroy <xavier.leroy@inria.fr>
Subject: Re: [Caml-list] string_of_float -> float_of_string locale dependency bug
Date: Mon, 14 Jun 2004 11:54:44 +0200

> The Caml runtime system does depend on the LC_NUMERIC locale begin set
> to its default value "C", but it ensures that this is the case by never
> calling setlocale(LC_ALL, "") nor setlocale(LC_NUMERIC, "").
> 
> Third-party libraries can invalidate this invariant by calling e.g.
> setlocale(LC_ALL, "").  Two possibilities:

Or applications which run ocaml script internally, which become
common recently.

Assuming a particular locale is quite problematic.

> 
> - The library doesn't really need LC_ALL, e.g. it would be enough
>   to set LC_CTYPE or LC_COLLATE and leave LC_NUMERIC unchanged.
>   In this case, the library should be fixed.
> 
> - The library really needs to set LC_NUMERIC, in which case it's
>   impossible to use that library with the Caml toplevel.

Camomile needs to set LC_ALL to acquire LC_NUMERIC value.  Camomile
does not use LC_NUMERIC value currently, but it provides API to
getting all LC_* values for the user.

> The C library API for internationalization is largely broken, and as
> you can see there is nothing we can do to work around the fact that
> the current locale is a global variable for the whole program.

You can temporally save the current LC_NUMERIC value, change its value
to C, and restore the value after the conversion.  What is a problem?

--
Yamagata Yoriyuki

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