func MyRegisterClass(hInstance win.HINSTANCE) (atom win.ATOM) { var wc win.WNDCLASSEX wc.CbSize = uint32(unsafe.Sizeof(wc)) wc.Style = win.CS_HREDRAW | win.CS_VREDRAW wc.LpfnWndProc = syscall.NewCallback(WndProc) wc.CbClsExtra = 0 wc.CbWndExtra = 0 wc.HInstance = hInstance wc.HbrBackground = win.GetSysColorBrush(win.COLOR_WINDOWFRAME) wc.LpszMenuName = syscall.StringToUTF16Ptr("") wc.LpszClassName = syscall.StringToUTF16Ptr(wndClassName) wc.HIconSm = win.LoadIcon(0, win.MAKEINTRESOURCE(win.IDI_APPLICATION)) wc.HIcon = win.LoadIcon(0, win.MAKEINTRESOURCE(win.IDI_APPLICATION)) wc.HCursor = win.LoadCursor(0, win.MAKEINTRESOURCE(win.IDC_ARROW)) return win.RegisterClassEx(&wc) }