Re: Symbols export control in libpoke

[Mohammad-Reza Nabipoor]

Hi, Jose.

On Sun, Oct 25, 2020 at 11:47:35AM +0100, Jose E. Marchesi wrote:
> 
> Hi people!
> 
> Right now we control which symbols get exported in libpoke by annotating
> function declarations with the "hidden" attribute, like in:
> 
>   pkl_compiler pkl_new (pvm vm, const char *rt_path)
>     __attribute__ ((visibility ("hidden")));
> 
> This works, but it is cumbersome to maintain and also error-prone: it is
> easy to forget to annotate new functions.
> 
> Some time ago Tim Ruehsen suggested to use a different strategy: to pass
> a flag to GCC so it marks all symbols to have hidden visibility by
> default, and then to annotate the function declarations in
> libpoke/libpoke.h.
> 
> I think the later approach is preferable.
> Opinions?
> 

I agree.

I think we can have a macro like this:

```c
#define LIBPOKE_API __attribute__ ((visibility ("default")))
```

and mark all the public functions with this macro.

Also we can have a list of all public functions in a separate file and add
a testcase to check the `libpoke.so` against that file.
This way maintaining a stable API is much simpler and less error-prone.
Adding/removing of symbols is also explicit.


Regards,
Mohammad-Reza