c++ Singleton with map cause "violation reading location" - c++

Question

I was trying to create a singleton to access a global-like class. This class work perfectly except when I use the std::map inside.
(yes i know, putting methods in .h..., but it's for debugging):
panthera.h
class Panthera
{
private:
std::map<std::string, std::map<long, Object *>> entities;
public:
Panthera(void);
~Panthera(void);
static Panthera * GetInstance()
{
static Panthera *engine_ = new Panthera();
return engine_;
}
void Run() {std::cout << "I run" << std::endl;}
void DOESNOTWORK(Object *o) {this->entities["test"][0] = o;}
};
main.cpp
Panthera::GetInstance()->Run(); // no problem
Panthera::GetInstance()->DOESNOTWORK(); // access violation
Been trying to solve this for some time now... Any leads?
After looking into things with OneonOne i understood that the problem was the class Object (it work if I replace it by anempty class)
tried to look in this class for incoherency/other but can't find the root of the problem, so here is the class
Object.h
#pragma once
#include "Vector2.h"
#include <list>
class Object
{
protected:
Vector2 location;
float rotation;
std::string plane;
unsigned long id;
std::list<Object *> children;
public:
Object(void);
Object(Vector2 const & location, std::string const & plane = "background", float rotation = 0);
Object(Object const & other);
~Object(void);
public:
virtual void SetLocation(Vector2 const & location);
virtual Vector2 GetLocation() const;
virtual void SetRotation(float);
virtual float GetRotation() const;
virtual void Move(Vector2 const & displacement);
virtual void Rotate(float angle);
virtual void Adopt(Object * other, Vector2 const & mountPoint = Vector2());
virtual Vector2 Mount(Vector2 const & other) const;
std::string GetPlane() const;
long GetId() const;
};
the implementation is trivial, and the class in itself run fine EXCEPT when it is added in a std::map and this only from a singleton...
As usual, thank you in advance for any help (and ask if you need the source file (or the Vector2 class))
As requested, the Object.cpp file
#include "Object.h"
#include "Matrix.h"
#include "Panthera.h"
Object::Object(void): location(Vector2()), rotation(0), plane("background")
{
this->id = reinterpret_cast<long>(this);
Panthera::GetInstance()->DOESNOTWORK(this);
}
Object::Object(Vector2 const & location, std::string const & plane, float rotation): location(location), rotation(rotation), plane(plane)
{
this->id = reinterpret_cast<long>(this);
//Panthera::GetInstance().Add(this);
}
Object::Object(Object const & other)
{
*this = other;
this->id = reinterpret_cast<long>(this);
// Panthera::GetInstance().Add(this);
}
Object::~Object(void)
{
}
void Object::SetLocation(Vector2 const & location)
{
this->Move(location - this->location);
}
Vector2 Object::GetLocation() const
{
return this->location;
}
void Object::SetRotation(float rotation)
{
this->Rotate(rotation - this->rotation);
}
float Object::GetRotation() const
{
return this->rotation;
}
void Object::Move(Vector2 const & displacement)
{
std::list<Object *>::iterator it;
for (it = this->children.begin() ; it != this->children.end(); ++it)
{
(*it)->Move(displacement);
}
this->location += displacement;
}
void Object::Rotate(float angle)
{
std::list<Object *>::iterator it;
for (it = this->children.begin() ; it != this->children.end(); ++it)
{
(*it)->SetLocation(Matrix::Transform((*it)->GetLocation() - this->location, angle) + this->location);
}
this->rotation += angle;
}
void Object::Adopt(Object * other, Vector2 const & mountpoint)
{
other->SetLocation(this->Mount(Matrix::Transform(mountpoint, this->rotation)));
this->children.push_back(other);
}
Vector2 Object::Mount(Vector2 const & other) const
{
return Vector2(this->location + other);
}
std::string Object::GetPlane() const
{
return this->plane;
}
long Object::GetId() const
{
return this->id;
}
Update: just calling the constructor of Object fails. for some reason it doesn't let me use the singleton in his constructor, => this is the root of the problem
Resolved: the problem was having a Object in the singleton class, the Object constructor made use of the singleton before it was initialized.

Answer 1

Your code doesn't even compile because your Constructor and Destruct weren't implemented.
Here's a C++11 version :
#include <unordered_map>
#include <iostream>
#include <string>
class Object {};
class Panthera {
private:
std::unordered_map<std::string, std::unordered_map<long, Object *>> entities;
Panthera() noexcept {}
public:
static Panthera & GetInstance() noexcept {
static Panthera engine_;
return engine_;
}
void Run() {std::cout << "I run" << std::endl;}
void worksnow() {this->entities["test"][0] = new Object;}
void get_test() {
std::cout << this->entities["test"].size() << std::endl;
}
};
int main() {
Panthera::GetInstance().Run(); // no problem
Panthera::GetInstance().worksnow(); //works too
Panthera::GetInstance().get_test();
return 0;
}
Test :
|---> clang++ -std=c++11 -stdlib=libc++ -lc++abi -I. test-singleton.cpp && ./a.out
I run
1
The original code works fine for me, so your problem is compiler related or with the omitted code :
#include <iostream>
#include <string>
#include <map>
class Object {};
class Panthera {
private:
std::map<std::string, std::map<long, Object *> > entities;
public:
Panthera(void) {}
~Panthera(void) {}
static Panthera * GetInstance() {
static Panthera *engine_ = new Panthera();
return engine_;
}
void Run() {std::cout << "I run" << std::endl;}
void DOESNOTWORK() {
this->entities["test"][0] = new Object;
std::cout << this->entities["test"].size() << std::endl;
}
};
int main() {
Panthera::GetInstance()->Run(); // no problem
Panthera::GetInstance()->DOESNOTWORK(); // access violation
return 0;
}