[완료]WIN 32 API - HWND 값이 NULL

#include <windows.h>
 
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
HINSTANCE g_hInst;
 
LPCTSTR lpszClass = TEXT("First");
LPCTSTR szTitle = TEXT("First");
 
int APIENTRY WinMain(HINSTANCE hInstance, 
					 HINSTANCE hPrevInstance, 
					 LPSTR lpszCmdParam, 
					 int nCmdShow)
{
	HWND hWnd;
	MSG Message;
	WNDCLASS WndClass;
	g_hInst = hInstance;
 
	//Register Class
	WndClass.cbClsExtra=0;
	WndClass.cbWndExtra=0;
	WndClass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
	WndClass.hCursor=LoadCursor(NULL, IDC_ARROW);
	WndClass.hIcon=LoadIcon(NULL, IDI_APPLICATION);
	WndClass.lpfnWndProc=WndProc;
	WndClass.lpszClassName=lpszClass;
	WndClass.lpszMenuName=NULL;
	WndClass.style=CS_HREDRAW|CS_VREDRAW;
	RegisterClass(&WndClass);
 
	//Init Instance
	hWnd = CreateWindow(lpszClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
 
	if (!hWnd)
	{
		return NULL;
	}
 
	ShowWindow(hWnd,nCmdShow);
 
	//Main message loop:
	while(GetMessage(&Message,NULL,0,0))
	{
		TranslateMessage(&Message);
		DispatchMessage(&Message);
	}
 
	return (int)Message.wParam;
 
}
 
LRESULT CALLBACK WndProc(HWND hWnd, UINT iMessage, WPARAM wParam, LPARAM lParam)
{
	switch(iMessage)
	{
	case WM_DESTROY:
		PostQuitMessage(0);
		return 0;
	}
	return (DefWindowProc(hWnd, iMessage, wParam, lParam));
}