apparently sdl doesn't work anymore on ios < 3.2 so it is worth to take the leap and upgrade the minimum os to 4.0, so that we can use new apis (like imageio from sdl_image)
#include <QApplication>
#include "mainform.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
MyWindow *mainWin = new MyWindow;
mainWin->show();
return app.exec();
}