프로그램을 종결해도 프로세스가 계속 살아있습니다.

#include <windows.h>
#include <tchar.h>
LRESULT CALLBACK WinProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK ChildProc(HWND, UINT, WPARAM, LPARAM);
HINSTANCE gIns;
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpcmdline, int nShowCmd) {
	WNDCLASS wndCls;
	wndCls.cbClsExtra=0;
	wndCls.cbWndExtra=0;
	wndCls.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
	wndCls.hCursor=LoadCursor(NULL, IDC_ARROW);
	wndCls.hIcon=NULL;
	wndCls.hInstance=gIns=hInstance;
	wndCls.lpfnWndProc=WinProc;
	wndCls.lpszClassName=TEXT("windowfrompoint");
	wndCls.lpszMenuName=NULL;
	wndCls.style=CS_HREDRAW | CS_VREDRAW;
	RegisterClass(&wndCls);
 
	wndCls.lpszClassName=TEXT("child window");
	wndCls.hbrBackground=(HBRUSH)GetStockObject(BLACK_BRUSH);
	wndCls.lpfnWndProc=ChildProc;
	RegisterClass(&wndCls);
 
	HWND hwnd=CreateWindow(  TEXT("windowfrompoint"), TEXT("windowfrompoint window"), WS_OVERLAPPEDWINDOW, 100, 100, 300, 300, NULL, NULL, hInstance, NULL  );
	ShowWindow(hwnd, nShowCmd);
	MSG message;
 
	while(  GetMessage(&message, hwnd, 0, 0)  ) {
		TranslateMessage(&message);
		DispatchMessage(&message);
	}
 
	return message.wParam;
}
HWND chWin;
LRESULT CALLBACK WinProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) {
	switch(message) {
		case WM_CREATE:
			{
				chWin=CreateWindow(TEXT("child window"), TEXT("child child"), WS_CHILD | WS_VISIBLE, 50, 50, 100, 100, hwnd, (HMENU)NULL, gIns, NULL);  
			}
			return 0;
		case WM_DESTROY:
			//DestroyWindow(chWin);
			PostQuitMessage(0);
 
			return 0;
	}
	return DefWindowProc(hwnd, message, wparam, lparam);
}
 
LRESULT CALLBACK ChildProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) {
	switch(message) {
		case WM_CREATE:
			MessageBox(hwnd, TEXT("child proc"), NULL, MB_OK);
			return 0;
		default:
			return DefWindowProc(hwnd, message, wparam, lparam);
	}
 
}