selective linking of floating point support for *printf / *scanf

[Joern Rennecke]

On 2 September 2014 16:28, Joseph S. Myers <joseph@codesourcery.com> wrote:
> On Tue, 2 Sep 2014, Joey Ye wrote:
>
>> 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?
>
> Identifiers beginning with a single underscore are reserved with file
> scope.  This means an application cannot provide an external definition of
> them, because such an external definition would have file scope.  So it's
> fine for the implementation to define such identifiers and use them in the
> implementation of standard functions.

Hmm, this trows up another question how in GNU C, extensions interact with
the putatively unchanged parts of the standard.
If a user program defines an assembler name for a global function which is
different from the name used in the source code, is that assembler name
used at file scope?  It would seem to me it's only used at global/link scope.
As such, is the use of _[a-z].* as assembly names then part of the
user namespace?