shared libs without linker scripts?

[Rusty Russell]

On Sat, 23 Jun 2012 15:25:47 -0400, simo <idra at samba.org> wrote:
> On Sat, 2012-06-23 at 12:44 +1000, Andrew Bartlett wrote: 
> > On Fri, 2012-06-22 at 21:21 -0400, simo wrote:
> > > I guess it depends on what you mean by 'safe'.
> > 
> > Exposure of internal implementation symbols in the exported symbols of
> > the shared library. 
> 
> Again I am not sure what you mean by safe, exposing symbols can cause
> symbols clashes, this is an inherent issue with C as C doesn't have a
> namespace.
> In order to reduce chance of clashes people tend to create a namespace
> by pre-pending a common prefix to public and private functions and where
> possible use exports lists/versions scripts to reduce the amount of
> symbols exposed.
> 
> But the fact internal symbols may be visible is not inherently an unsafe
> condition.

Yes.  If you don't have symbol visibility control, you inevitably leak
some symbols.

But AFAICT you generally get away with it: if library A and library B
both contain a 'foo' symbol, A will use A's, and B will use B's.  (Does
someone have such a system where they can verify?).

However, if 'foo' was a symbol which program C used, it could get
either.

But this just means that you should ensure namespace on
meant-to-be-public symbols, which you should do regardless.

Cheers,
Rusty.