Почему CreateWindow может возвращать NULL? - Visual C++ - Ответ 8744

//Win_App_17_07.cpp
#include "stdafx.h"
#include "Win_App_17_07.h"
 
TCHAR ClassName [100];
TCHAR Title [100];
 
ATOM RegClass (HINSTANCE);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
 
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
LoadString(hInstance, IDS_CLASS_NAME, ClassName, 100);
LoadString(hInstance, IDS_TITLE, Title, 100);
 
RegClass (hInstance);
 
HWND hWnd;
hWnd = CreateWindow(ClassName, Title, WS_OVERLAPPEDWINDOW, 
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
 
if (!hWnd) return FALSE;
ShowWindow(hWnd,nCmdShow);
UpdateWindow(hWnd);
 
MSG msg;
while (GetMessage(&msg,NULL,0,0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return 0;
}
 
 
ATOM RegClass(HINSTANCE hInst)
{
WNDCLASSEX wcx;
wcx.cbSize = sizeof(WNDCLASSEX);
wcx.style = CS_VREDRAW|CS_HREDRAW;
wcx.lpfnWndProc = WndProc;
wcx.cbClsExtra = 0;
wcx.cbWndExtra = 0;
wcx.hInstance = hInst;
wcx.hIcon = LoadIcon(NULL, IDI_WARNING);
wcx.hCursor = LoadCursor(NULL, IDC_ARROW);
wcx.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
wcx.lpszMenuName = NULL;
wcx.lpszClassName = ClassName;
wcx.hIconSm = NULL;
 
return RegisterClassEx(&wcx);
}
 
LRESULT CALLBACK WndProc (HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
HDC hdc;
PAINTSTRUCT ps;
switch (message)
{
case WM_PAINT:
{
hdc = BeginPaint(hWnd,&ps);
EndPaint(hWnd,&ps);
return 0;
}
case WM_DESTROY: PostQuitMessage(0); return 0;
default : DefWindowProc(hWnd, message, wParam, lParam); return 0;
}
}
 
 
 
///файл resource.h
// Microsoft Visual C++ generated include file.
// Used by Main.rc
//
#define IDS_CLASS_NAME 101
#define IDS_TITLE 102
 
// Next default values for new objects
// 
#ifdef APSTUDIO_INVOKED
#ifndef APSTUDIO_READONLY_SYMBOLS
#define _APS_NEXT_RESOURCE_VALUE 103
#define _APS_NEXT_COMMAND_VALUE 40001
#define _APS_NEXT_CONTROL_VALUE 1001
#define _APS_NEXT_SYMED_VALUE 101
#endif
#endif