Propagating addresses from linker to the runtie

[Segher Boessenkool]

On Fri, Oct 18, 2019 at 03:20:41PM +0200, Josef Wolf wrote:
> On Fri, Oct 18, 2019 at 07:51:38AM -0500, Segher Boessenkool wrote:
> [ ... ]
> > Using reserved names (like those starting with two underscores) is UB
> > already.
> 
> What does "UB" mean?

Undefined behaviour.  I should have spelled that out, sorry.

> I was talking about exporting start+length instead of start+stop.
> 
> Having start+length would allow a confirming implementation, because pointer
> arithmetic on unrelated objects would no longer be needed:
> 
>     unsigned long *dst = &_s_bss;
>     for (n = 0; n < _l_bss / sizeof (unsigned long); n++)
>         dst[n] = 0;

Using anything like these symbols is not conforming *already*.

You can spell out exactly what implementation behaviour your program expects
in your documentation, that is much more realistic than saying "conforming".


Segher