И така "взимаме" текущата резолюция 
#include "wtypes.h"
#include "iostream"
using namespace std;

void GetDesktopResolution(int& horizontal, int& vertical) {
    RECT desktop;
    const HWND hDesktop = GetDesktopWindow();
    GetWindowRect(hDesktop, &desktop);
    horizontal = desktop.right;
    vertical = desktop.bottom;
}
компилатор: gnu gcc