Re: Guile, C++, and Mac OS X 10.4 (powerpc)

[Hans Aberg]

On 18 Aug 2010, at 15:49, Ludovic Courtès wrote:

> > > Hey guile users,
> > >   Trying to compile the simple example bessel.c from
> > > Writing-Guile-Extensions.html (renamed bessel.cc because I'm using
> > > g+
> > > +), I
> > > encountered the following error:
> > >
> > > bessel.cc: In function 'void init_bessel()':
> > > bessel.cc:13: error: invalid conversion from 'scm_unused_struct*
> > > (*)(scm_unused_struct*)' to 'scm_unused_struct* (*)(...)'
> > > bessel.cc:13: error:   initializing argument 5 of  
> > > 'scm_unused_struct*
> > > scm_c_define_gsubr(const char*, int, int, int, scm_unused_struct*
> > > (*)
> > > (...))'
> >
> > The SCM type is a pointer to an undefined C type - C hack, which
> > clashes with C++. Clever in C, but bad for C++ users.
>
> I don’t think that this is the cause of the problem.
>
> The problem instead stems from use of function declarators with empty
> parenthesis, which is also an obsolescent C feature, as discussed  
> here:
>
>  http://savannah.gnu.org/bugs/?23681
>
> I fixed a few of these in Guile 1.9, but not all of them, and not
> ‘scm_c_define_gsubr’ in particular.
>
> I would appreciate patches in this area.  :-)

I got those when doing a templates in a C++ wrap, and just assumed it  
had something to do with that SCM was a pointer.