memory alllocation wxWidgets

Question

I tried to have a dynamic memory allocation inside my application. If I try to allocate memroy in OnInit() then the application crashes.

Currently I'm using the lastest stable version of wxWidgets 3.0.4 with Visual Studio 2010.

If I comment #define BUFFER the application works as expected.

my main.h:

#include <wx/wx.h>

class MyApp : public wxApp {
    public:
        virtual bool OnInit();
};

class MainWindow : public wxFrame {
    public:
        MainWindow(const wxPoint& position, const wxSize& size);
        ~MainWindow();

    private:
        void setupUi();

        int *buffer0;
};

main.cpp

#include "main.h"

#define BUFFER
IMPLEMENT_APP(MyApp)

//-----------------------------------------------------------------------------
bool MyApp::OnInit() {
    MainWindow *main = new MainWindow(wxPoint(20, 20), wxSize(300, 200));
    main->Show(true);

    return true;
}


//----------------------------------------------------------------------------
MainWindow::MainWindow(const wxPoint& position, const wxSize& size) : wxFrame(NULL, wxID_ANY, "Frame") {
    setupUi();
#ifdef BUFFER
    buffer0 = new int(1000);
    memset(buffer0, 0, 10 * sizeof(int));
#endif
}


//----------------------------------------------------------------------------
MainWindow::~MainWindow() {
#ifdef BUFFER
    delete[] buffer0;
#endif
}

//----------------------------------------------------------------------------
void MainWindow::setupUi() {
    wxBoxSizer *bsMain = new wxBoxSizer(wxVERTICAL);
    wxStaticBox *sbInfo = new wxStaticBox(this, wxID_ANY, "INFORMATION");

    bsMain->Add(sbInfo, 1, wxALL | wxEXPAND, 15);
    SetSizer(bsMain);
}

Answer 1

With

buffer0 = new int(1000);

you allocate memory for 1 (in words: one) int and initialize it with 10000. Then with

memset(buffer0, 0, 10 * sizeof(int));

you set 10 * sizeof(int) bytes starting at buffer to zero. You access memory that isn't yours.

Since you use delete[] in your destructor I guess you wanted to write

buffer0 = new int[1000];

or even

buffer0 = new int[1000]{};

to initialize the ints with zero without having to use memset().

---

The Real^(tm) Answer:

Use

std::vector<int> buffer0(1000);