Possibility to make __global_locale const to reduce RAM usage?

Possibility to make __global_locale const to reduce RAM usage?

[Damien George]

Hello,

As others have already noticed (see
https://sourceware.org/ml/newlib/2017/msg00192.html and
https://sourceware.org/ml/newlib/2017/msg00368.html), since newlib 2.5.0
the locale support pulls in the __global_locale struct which takes around
360 bytes of RAM, which is a lot on a resourced constrained microcontroller.

Would it be possible to make this data structure "const" so that it goes in
.text/.rodata/ROM instead of in .data/RAM?  From a brief look at the code
it looks like this structure is usually only ever read from, not written
to, so this may be a possibility.

Best regards,
Damien.

Re: Possibility to make __global_locale const to reduce RAM usage?

[Corinna Vinschen]

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On Oct 19 12:00, Damien George wrote:
> Hello,
> 
> As others have already noticed (see
> https://sourceware.org/ml/newlib/2017/msg00192.html and
> https://sourceware.org/ml/newlib/2017/msg00368.html), since newlib 2.5.0
> the locale support pulls in the __global_locale struct which takes around
> 360 bytes of RAM, which is a lot on a resourced constrained microcontroller.
> 
> Would it be possible to make this data structure "const" so that it goes in
> .text/.rodata/ROM instead of in .data/RAM?  From a brief look at the code
> it looks like this structure is usually only ever read from, not written
> to, so this may be a possibility.

It's basically written to every time you call setlocale.  Patches are
welcome which disable the localization stuff entirely for embedded
devices.


Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat

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