Why does SDL doesn't emit SDL_QUIT when last windows closed - c++

Question

I'm writing a Game Engine just for practice but I still stuck with the first chellange. The Window Manager.
https://github.com/thebenius/SDL
I've created a GitHub Repo to show you the code but don't worry. Its not much. But I absolutely don't know where is my mistake.
In the Code I create three Windows and I Manage the input for SDL_QUIT to stop the game loop and for SDL_WINDOWEVENT_CLOSE to close the windows.
Everything works fine until the last window is closed. As far as I know, now the SDL_QUIT Event must be emitted by SDL. But the Gameloop goes on.
I think I maybe have a kind of memory leak and there is still a windows saved. But I checked the window stack (Window::windows hashmap) it is empty. And also the variables in main are cleared.
I also tried to additionally clear the window and renderer variable in the hash map
Window::~Window() {
// Delete Window and Renderer
SDL_DestroyRenderer(Window::windows[this->windowID]->renderer);
SDL_DestroyWindow(Window::windows[this->windowID]->window);
Window::windows[this->windowID]->renderer = nullptr;
Window::windows[this->windowID]->window = nullptr;
// Delete Window from map
Window::windows.erase(this->windowID);
// Delete Window and Renderer
SDL_DestroyRenderer(this->renderer);
SDL_DestroyWindow(this->window);
// Reset Pointer
this->renderer = nullptr;
this->window = nullptr;
Nothing worked.
I'm new in C++ and SDL. I hope you can help me out.

Answer 1

Thank you o11c,
Your answer was the riddles solution.
I just put SDL_Quit() out of the Destructor. This obviously blocked the Event Handler to catch SDL_QUIT. So I put it to the constructor in atexit()
After that (don't know why before not) I got an Segfault when deleting the window pointer in main. I deleted that and just set them all to nullptr.
Now the WindowManager works properly. Thank you for your help

Answer 2

I think SDL_QUIT is only an hook called if you call SDL_Quit(), to give the user the opportunity to do some quit stuff, the manual:
You should call this function even if you have already shutdown each initialized subsystem with SDL_QuitSubSystem(). It is safe to call this function even in the case of errors in initialization
You can use this function with atexit() to ensure that it is run when your application is shutdown, but it is not wise to do this from a library or other dynamically loaded code
To catch a window close event see SDL_WindowEvent, SDL_WINDOWEVENT and SDL_WINDOWEVENT_CLOSE, the id of the closing window is given as argument.
* \file SDL_quit.h
*
* An ::SDL_QUIT event is generated when the user tries to close the application
* window. If it is ignored or filtered out, the window will remain open.
* If it is not ignored or filtered, it is queued normally and the window
* is allowed to close. When the window is closed, screen updates will
* complete, but have no effect.
*
* SDL_Init() installs signal handlers for SIGINT (keyboard interrupt)
* and SIGTERM (system termination request), if handlers do not already
* exist, that generate ::SDL_QUIT events as well. There is no way
* to determine the cause of an ::SDL_QUIT event, but setting a signal
* handler in your application will override the default generation of
* quit events for that signal.
*
* \sa SDL_Quit()
SDL_EventType#SDL_QUIT
An SDL_QUIT event is generated when the user clicks on the close button of the last existing window.
You shouldn't call SDL_Quit() in the destructor, but only once before leaving the application (is suggested to use it with atexit())
--- a/main.cpp
+++ b/main.cpp
## -32,17 +32,18 ## int main() {
}
-
// Delete Windows
- delete window;
- delete window2;
- delete window3;
+ // delete window;
+ // delete window2;
+ // delete window3;
// reset pointer
window = nullptr;
window2 = nullptr;
window3 = nullptr;
+ SDL_Quit();
+
// Close Program properly
return 0;
}
--- a/video/window.cpp
+++ b/video/window.cpp
## -51,7 +51,7 ## Window::~Window() {
// Shutdown if last window closed
if(this->windows.empty()) {
// Shutdown Video System
- SDL_Quit();
+ // SDL_Quit();
std::cout << "shuted down Video" << std::endl;
}
}