[cppyy] GetNumMethods for namespaces

alexandrumc · August 5, 2020, 4:44pm

Hi,

I’ve tried to use this function, but it returns 0 for namespaces.

Any ideas on how to avoid that?

Thanks!

oshadura · August 6, 2020, 8:05am

@etejedor is in vacation but I hope he will be reply as soon as he will back…

etejedor · August 10, 2020, 12:40pm

Hello,

If I understand correctly, you are trying to use an internal Cppyy function from your code? Could you give me some context?

alexandrumc · August 11, 2020, 8:29am

Hello,

Sorry, no, I’m not calling the internal function, I’m calling this function that calls the internal one:

github.com

root-project/root/blob/414fbd3862573e603621ebb19d0331279bc65be3/bindings/pyroot/cppyy/cppyy-backend/clingwrapper/src/clingwrapper.cxx#L2384


}


/* calculate offsets between declared and actual type, up-cast: direction > 0; down-cast: direction < 0 */
ptrdiff_t cppyy_base_offset(cppyy_type_t derived, cppyy_type_t base, cppyy_object_t address, int direction) {
    return (ptrdiff_t)Cppyy::GetBaseOffset(derived, base, (void*)address, direction, 0);
}


/* method/function reflection information --------------------------------- */
int cppyy_num_methods(cppyy_scope_t scope) {
    return (int)Cppyy::GetNumMethods(scope);
}

cppyy_index_t* cppyy_method_indices_from_name(cppyy_scope_t scope, const char* name)
{
    std::vector<cppyy_index_t> result = Cppyy::GetMethodIndicesFromName(scope, name);

    if (result.empty())
        return (cppyy_index_t*)nullptr;

The context is simple: I have a cppyy_scope_t object which is, in fact, a namespace; for this namespace, I want to know how many free functions are inside it, but I can’t use the function from above because it simply returns 0 for namespaces. So basically I need a workaround for this.

etejedor · August 11, 2020, 10:08am

Hi,

I see, if you are trying to implement a C++ library on top of cppyy directly, I would recommend that you use the upstream cppyy (instead of the cppyy distributed with ROOT, see https://cppyy.readthedocs.io/en/latest/ for more information) and you will be able to get support for cppyy-backend functions from the cppyy developers.