void WinHandler(WM_MESSAGE * pMsg)
{

switch (pMsg->MsgId)
{
case WM_PAINT:
GUI_SetBkColor(0xFF00);
GUI_Clear();
GUI_DispStringAt("Hello world",0,0);
break;
case WM_CREATE:
hButton = BUTTON_Create(0,0,50,50,1,WM_CF_SHOW);
BUTTON_SetText(hButton,"Press");
break;
case WM_TOUCH:
if(BUTTON_IsPressed(hButton)==1) GUI_DispString("buttona basildi\n");

default:
WM_DefaultProc(pMsg);
}
}

void sdram_init(void);

int main(void)
{
WM_HWIN hid;

SystemInit();
SystemCoreClockUpdate();
SysTick_Config(SystemCoreClock / 1000);
sdram_init();//buna bir hal çare bulmaliyim
GUI_Init();
WM_CreateWindow(20,20,100,100,WM_CF_SHOW ,WinHandler,0);

while(1)
{
GUI_Delay(1);
}
}

ı dont understand where am ı wrong? Please help?