WxWidgets Sizer Double Frees? - c++

Question

I'm going to preface this question by saying that I am not entirely new to wxWidgets, though I would not consider myself all that experience either.
I'm having a problem which I have narrowed down through testing to be with the wxWidgets wxBoxSizer classes. From what I can tell, I don't think I'm doing anything wrong, and they work while the application is running; however, when the application closes and everything terminates, it seems that about a third of the time it will double-free something and seg fault. I'm writing and building on a linux system, and there doesn't seem to be any problems with anything but these sizers.
I did have many more windows within the HomeFrame class before I stripped it to search for bugs, but the code below still causes the double-free:
I've also looked around StackOverflow and other code forums to see if anyone was having a similar issue, but I couldn't find anything. I'm thinking that it may have something to do with the way I'm storing the sizer pointers in the class as members?
HomeFrame.h:
#pragma once
#include <wx/frame.h>
#include <wx/sizer.h>
namespace qzrgui
{
class HomeFrame: public wxFrame
{
public:
HomeFrame();
~HomeFrame();
private:
// Sizers
wxBoxSizer* _topSizer;
wxBoxSizer* _leftSizer;
wxBoxSizer* _rightSizer;
// Functions
void _setup();
void _createWindows();
};
}
HomeFrame.cpp:
#include "HomeFrame.h"
namespace qzrgui
{
HomeFrame::HomeFrame() :
wxFrame(nullptr, wxID_ANY, "Quizzer")
{
_setup();
}
HomeFrame::~HomeFrame()
{
}
void HomeFrame::_createWindows()
{
// Create sizers.
_topSizer = new wxBoxSizer(wxOrientation::wxHORIZONTAL);
_leftSizer = new wxBoxSizer(wxOrientation::wxVERTICAL);
_rightSizer = new wxBoxSizer(wxOrientation::wxVERTICAL);
}
void HomeFrame::_setup()
{
_createWindows();
}
}
Quizzer.h (wxApp base class):
#pragma once
#include <wx/app.h>
namespace qzrgui
{
class Quizzer : public wxApp
{
public:
virtual bool OnInit();
};
};
Quizzer.cpp:
#include "Quizzer.h"
wxIMPLEMENT_APP(qzrgui::Quizzer);
#include "frames/HomeFrame.h"
namespace qzrgui
{
bool Quizzer::OnInit()
{
wxFrame* frame = new HomeFrame();
frame->Show(true);
return true;
}
}

Answer 1

There is nothing in the code shown here which could result in a crash. You do definitely have (three) memory leak(s) in your code, as you create 3 sizers not associated with any window or another sizer and never delete them, but, while wrong, this can't result in a crash.
There is also not enough information to diagnose what you're seeing. As always with a crash, please build your code with debug information and run it under debugger to see what exactly happens. If you're under a Unix-like system (or even under MSW with the latest MSVS 2019 version), you should also compile with address sanitizer enabled to find the real problem before the crash happens.