Win32 API WM_CLOSE
示例
单击应用程序的关闭按钮时发送。请勿将其与WM_DESTROY销毁窗口时发送的内容混淆。主要区别在于，可以在WM_CLOSE中取消关闭（考虑到MicrosoftWord要求保存所做的更改），而销毁是因为窗口已经关闭（考虑到MicrosoftWord释放内存）。
LRESULT CALLBACK winproc(HWND hwnd, UINT wm, WPARAM wp, LPARAM lp)
{
static char *text;
switch (wm) {
case WM_CREATE:
text = malloc(256);
/* use the allocated memory */
return 0;
case WM_CLOSE:
switch (MessageBox(hwnd, "Save changes?", "", MB_YESNOCANCEL)) {
case IDYES:
savedoc();
/* fall through */
case IDNO:
DestroyWindow(hwnd);
break;
}
return 0;
case WM_DESTROY:
/* free the memory */
free(text);
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hwnd, wm, wp, lp);
}