如何在Borland C++中禁用主窗体的关闭

#include<windows.h>
#include <CommCtrl.h>

LRESULT CALLBACK MainWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_CLOSE:
        // 阻止窗口关闭
        return 0;

    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
}

WNDCLASSEX wcex = {0};
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = MainWndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_APPLICATION));
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wcex.lpszMenuName = NULL;
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_APPLICATION));

RegisterClassEx(&wcex);

HWND hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
    CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);