plugin_register "csurf_inst" produces a bug and doesn't work when called from a loaded VST3 plugin

[GZPERRA]

I'm trying to register the "csurf_inst" from a loaded VST3 plugin, to listen for tracks selection changes, and it's producing a bug. This is the code:

void registerCSurf() {
  auto reaper = // queryInterface(IReaperHostApplication::iid ...
  if (reaper)
  {
    auto registerFunc = static_cast<int (*)(const char*, void*)>(reaper->getReaperApi("plugin_register"));

    if (registerFunc)
    {
        if (1 == registerFunc("csurf_inst", this)) // *this* implements IReaperControlSurface.
        {
            Log::debug("register csurf_inst Ok");
        }
    }
    //reaper->release();
  }
}

The registerFunc returns 1, but no function (Run,OnTrackSelection,SetSurfaceXXX..) gets called. But what happens is that the selection becomes broken, I can't deselect tracks, unmute ...

[justinfrankel]

It's hard to know exactly what's going on based on the limited scope of your code, but it's likely that you need to change the register line to be: if (1 == registerFunc("csurf_inst", (void *)(IReaperControlSurface*)this))

otherwise, the cast to void * will not know which interface it should be passing