If you have created wxWidgets app using wxSmith project wizard, main resource may be configured inside menu: wxSmith -> Configure wxSmith for current project.
If not, there's application class required:
app.h:
#ifndef APP_H
#define APP_H
#include <wx/wxprec.h>
#ifdef __BORLANDC__
#pragma hdrstop
#endif
#ifndef WX_PRECOMP
#include <wx/wx.h>
#endif
class MyApp : public wxApp
{
public:
virtual bool OnInit();
};
#endif // APP_H
app.cpp:
#include "app.h"
#include "yourframe.h"
IMPLEMENT_APP(MyApp);
bool MyApp::OnInit()
{
FrameClass* frame = new FrameClass(0);
if ( !frame ) return false;
frame->Show();
return true;
}