C++ - WINAPI - Object-oriented approach to closing a window - c++

Question

While trying to create a nice wrapper around Win32 specific GUI components, I eventually ran into a problem. The problem is that I'm unable to close the application after the windows I created no longer exist.
My API works like this:
/// ----------------------------
/// #author God
/// #project Helixirr Widgets
/// ----------------------------
#include <helixirrwidgets/HelixirrWidgets.hpp>
int main(void){
HelixirrWidgets::Window __windows[2] = {HelixirrWidgets::Window("Big Window"), HelixirrWidgets::Window()};
__windows[0].position(200, 200);
__windows[0].size(800, 600);
__windows[0].visible(true);
__windows[0].save_changes();
__windows[1].name("Tiny Window");
__windows[1].position(10, 100);
__windows[1].size(400, 200);
__windows[1].visible(true);
__windows[1].save_changes();
while(__windows[0].active() || __windows[1].active()){
if(__windows[0].visible()){
__windows[0].show();
}
if(__windows[1].visible()){
__windows[1].show();
}
}
return 0;
}
In method of HelixirrWidgets::Window called "active", which is declared like this
inline bool active(void) const noexcept;
I can check, whether my window is active or not.
This method basically return a const reference to a boolean member variable of an instance. This member variable is modified in "show"-method of the same class. Here's the definition:
void Window::show(void){
if(GetMessage(&_m_opHelper->message, _m_opHelper->handle_window, 0, 0)){
if(_m_opHelper->message.message == WM_CLOSE){
_m_bActive = false;
return;
}
TranslateMessage(&_m_opHelper->message);
DispatchMessage(&_m_opHelper->message);
ShowWindow(_m_opHelper->handle_window, SW_SHOWDEFAULT);
UpdateWindow(_m_opHelper->handle_window);
_m_bActive = true;
return;
}
_m_bActive = false;
}
Do note I use pimpl-idiom to hide platform-specific structures ("_m_opHelper" is pointer to implementation).
It may look like it works, but it doesn't and I can't understand why. It all comes down to a simple question: how can I close my window implemented using WINAPI specific functions and structures to be closed appropriately by a user of my application?

Answer 1

I guess the cause of the issue is related to the fact WM_CLOSE simply is not last message HWND gets. Messages like WM_DESTROY, WM_NCDESTROY and possibly more (depending on the particlar window and its state) will come after WM_CLOSE, leading to the assignment _m_bActive = TRUE.
I.e. the window becomes inactive for very short time, and (likely) they will never be inactive at the same time, causing an endless loop in main().