How to forward declare dlib::frontal_face_detector?

Question

I'm trying to forward declare couple of dlib classes, but it seems what I'm doing is wrong. Currently I have tried this:

"myheader.h":

namespace dlib 
{
    class frontal_face_detector;
    class shape_predictor;
    class full_object_detection;
}

class MyClass:
{
public: 
    void start();

private:
    void test(dlib::full_object_detection* result);

dlib::fronta_face_detector* detector;
dlib::shape_predictor predictor;
dlib:: full_object_detection result;
};

and in myheader.cpp:

#include <dlib/image_io.h>
#include <dlib/opencv.h>
#include <dlib/image_processing/frontal_face_detector.h>
#include <dlib/image_processing/render_face_detections.h>
#include "myheader.h"

MyClass::MyClass()
{
    this->detector = new dlib::frontal_face_detector();
    this->predictor = new dlib::shape_predictor();
}
void MyClass:test(dlib::full_object_detection * result)
{
  //...
}

but this doesn't work apparently, what am I missing here? Is it because it's defined not as a class but as a typedef?

    typedef object_detector<scan_fhog_pyramid<pyramid_down<6> > > frontal_face_detector;

If so, how should I go about this aside from pimpling MyClass?

As you are using the types as class members they can't be forward declared. You can replace the members with pointers or use pimpl to hide them completely — Alan Birtles, Aug 17 '20 at 06:28
@AlanBirtles Thanks alot really appreciate it, so the only way would be pimpl. if I defined the types as void* and then initialize them with actual data in constructor, would that be a good idea as well? (casting and recasting aside). my worry is that, since the object is local to the constructor, the void* will point to invalid location outside of constructor. is it right (sorry its been couple of years since I worked in c++ and things are a bit fuzzy now!) — Hossein, Aug 17 '20 at 06:32
there wouldn't be any benefit to using `void*`, typed pointers would work just as well — Alan Birtles, Aug 17 '20 at 07:11

How to forward declare dlib::frontal_face_detector?

0 Answers0