Re: Build option to disable locale [was: Byte-based C locale, draft 1]

[Isaac Dunham <ibid.ag@gmail.com>]

On Mon, Jun 08, 2015 at 04:46:42AM +0200, Harald Becker wrote:
> On 08.06.2015 02:33, Rich Felker wrote:
> >So aside from iconv, the above seem to total around 19k, and at least
> >6k of that is mandatory if you want to be able to claim to support
> >UTF-8. So the topic at hand seems to be whether you can save <13k of
> >libc.so size by hacking out character handling/locale related features
> >that are non-essential to basic UTF-8 support...
> 
> I like to get a stripped down version, which eliminate all the unnecessary
> char set handling code used in dedicated systems, but stripping that on
> every release is too much work to do.
> 
> The benefit may be for:
> 
> - embedded systems
> - small initramfs based systems
> - container systems
> - minimal chroot environments

Somehow it sounds like you may not have gotten wat Rich was asking.

IIRC, the goals of musl include full native support for UTF-8; keeping 
the time complexity to a minimum; and clean, correct code.

Dropping out 'legacy' charsets doesn't really sacrifice those goals.
But the other changes are have a much bigger impact on them.
So you're probably going to have to convince Rich that there *is* a
major benefit ('is' != 'could be').

For container systems or minimal chroot environments, you're dealing
with something that doesn't have a hard size limit, and if a chroot
or container runs ~6 MB ordinarily, you might be able to run 0.3% more
on the same hardware. That's probably not enough of a case.
For initramfs-based systems, you've got a similar situation but no
chance to multiply the effect, unless you're using a VM or hypervisor.

Now, since embedded systems have hard limits on size, you might be
able to make a case there. But you will need to come up with somthing
more specific, such as "I have a system where I could upgrade the kernel
to 2.6.xx *if* musl were ~20k smaller than building with a minimal
iconv" or "If we did this, there would be enough space to switch XYZ
router firmware from telnetd to dropbear".

HTH,
Isaac Dunham