C function which return values of type *ppl_Polyhedron_t** rather
On Tuesday, February 17, 2015 at 8:40:16 PM UTC-5, Zenna Tavares wrote:
>
> I'm trying to wrap the Parma Polyhedron Library in Julia.
>
> The library itself is written in C++, I am trying to wrap the C API.
>
> Consider a snippet of an C example which uses the C API
>
> static int
> solve_with_generators(ppl_Constraint_System_t ppl_cs,
> ppl_const_Linear_Expression_t ppl_objective_le,
> ppl_Coefficient_t optimum_n,
> ppl_Coefficient_t optimum_d,
> ppl_Generator_t point) {
> ppl_Polyhedron_t ppl_ph;
> ...
> /* Create the polyhedron (recycling the data structures of ppl_cs). */
> ppl_new_C_Polyhedron_recycle_Constraint_System(&ppl_ph, ppl_cs);
>
>
>
> To illustrate my problem, consider the call to*
> ppl_new_C_Polyhedron_recycle_Constraint_System* which creates a
> constraint system, and has signature:
>
> ppl_new_C_Polyhedron_recycle_Constraint_System(ppl_Polyhedron_t* pph,
> ppl_Constraint_System_t cs)
>
>
>
> *ppl_Polyhedron_*t is typedef generated using macros, but effectively it
> is defined by
>
> typedef struct ppl_Polyhedron_tag* ppl_Polyhedron_t;
>
> I can't find anywhere in the source where these structs are defined, but
> presumably they must (my C is very rusty). In any case, the problem is
> that from Julia I don't have access to these typedefs. If I want to ccall
> *ppl_new_C_Polyhedron_recycle_Constraint_System*, what can I use as the
> first and second arguments? My (currently very naive) intuition is that I
> need C functions which return values of the type *ppl_Polyhedron_t* for
> instance, but it seems this API does not follow that pattern. Is this
> correct? Will I need to do something like write another C API which just
> returns pointers? Or is there a simpler solution?
>
> Thanks
>
