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Re: selective linking of floating point support for *printf / *scanf
- From: Joey Ye <joey dot ye dot cc at gmail dot com>
- To: "Thomas Preud'homme" <thomas dot preudhomme at arm dot com>
- Cc: Grissiom <chaos dot proton at gmail dot com>, Eric Blake <eblake at redhat dot com>, Joern Rennecke <joern dot rennecke at embecosm dot com>, GCC <gcc at gcc dot gnu dot org>, Joerg Wunsch <joerg_wunsch at uriah dot heep dot sax dot de>, avr-libc-dev at nongnu dot org, Andrew Burgess <andrew dot burgess at embecosm dot com>, "newlib at sourceware dot org" <newlib at sourceware dot org>
- Date: Tue, 2 Sep 2014 15:33:00 +0800
- Subject: Re: selective linking of floating point support for *printf / *scanf
- Authentication-results: sourceware.org; auth=none
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On Sat, Aug 30, 2014 at 12:26 PM, Thomas Preud'homme
>> From: Grissiom [mailto:firstname.lastname@example.org]
>> Sent: Friday, August 29, 2014 11:51 PM
>> Yes, it does. The namespace reserved for the implementation is _[_A-Z].
> > The namespace _[a-z] is still available for the user. Which means the
>> user can declare their own _printf_float, and WE (as the implementation)
>> MUST NOT INTERFERE with it. Since WE are the implementation, we should
>> use the namespace reserved for us, namely __printf_float.
> Mmmh indeed. I checked C99 and section 7.1.3 paragraph 1 third clause states:
> "All identifiers that begin with an underscore and either an uppercase letter or
> another underscore are always reserved for any use."
> Next clause express how single underscore not followed by a capital letter is
> "All identifiers that begin with an underscore are always reserved for use as identifiers
> with file scope in both the ordinary and tag name spaces."
Apparently newlib is not following this specification very well, as
there are symbols like _abc_r defined every where in current newlib. I
am not implying the spec should not be followed, but is newlib
designed to have a loose spec for the single underscore?
> Since here we are talking about linkage, _printf_float is not safe according to the
> Ok I need to think about it. Thank you all for pointing out the problem with the
> current scheme.
> Best regards,