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Date: Thu, 1 Oct 2020 07:24:19 +0200
From: Ellie <>
To: Rich Felker <>
Subject: Re: Would it to be possible to get strtoll_l?

Just to add to this after even more thinking, it also seems conceptually
weird to me: why litter additional calls at all when a parameter would
do? Why "fight" any untrusted function by reverting locale changes, or
alternatively "protect" all my own calls against unexpected locale
evildoers when I could just specify all the info with parameters instead
of half of it? It's not like the string functions are already
overflowing with parameters right now.

It just seems like a weird design to me, personally. On the BSDs, the
*_l() functions seem to commonly exist by default (not guarded with
_GNU_SOURCE or other extension macros), I assume it's because they
likely thought similarly that the state machine setlocale/uselocale
approach just is oddly clumsy in comparison.

But maybe that's just me?



On 10/1/20 6:36 AM, ell1e wrote:
> Thinking more about this, this seems like it might be the less
> performant option to me, although I'd be happy to take your thoughts on
> this:
> I'm thinking, it would require me to reset the thread locale before and
> after each C call (I'm working in a bytecode VM here), and it seems like
> just passing an additional locale parameter is going to be faster. I
> haven't benchmarked however, if you doubt this assumption I will look
> into it. But it seems to me that an additional parameter is preferable
> for a few of the string operations to making 2+ additional calls around
> each call into C.
> But given the above guess, my spontaneous preference would still be to
> rather use strtoll_l(). It is also available in glibc, it's just missing
> in musl libc, which is why I sent this e-mail.
> On 10/1/20 4:35 AM, Rich Felker wrote:
>> On Thu, Oct 01, 2020 at 02:34:47AM +0200, ell1e wrote:
>>> Hi everyone,
>>> I'm working on a project and since the global state setlocale() seems to
>>> be a bit of a mess to rely on, I'm using the *_l() string functions
>>> instead. However, musl libc appears to lack strtoll_l() right now, so
>>> I'm wondering if that'll be added any time soon?
>> The portable way to do this is just calling uselocale() rather than
>> passing the locale_t to individual *_l functions. You can even
>> implement a fallback strtoll_l as:
>> localt_t old = uselocale(l);
>> result = strtoll(a,b,c);
>> uselocale(old);
>> It's slightly more efficient if you keep the uselocale across multiple
>> calls, but not that big a deal; uselocale is an extremely light
>> operation.
>> But is there a reason you don't just want plain strtoll? C allows that
>> "additional locale-specific subject sequence forms may be accepted" in
>> locales other than the C locale, but does not permit standard
>> sequences to be interpreted differently, and in practice I'm not aware
>> of implementations that do anything funny here.
>> Rich

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