Menu
I have a C++ Win32 application written using Win32 API and I wish to force it to exit in one of functions. Is there something like Exit() or Destroy() or Abort() something similar that would just terminate it?
661
Alternatively referred to as the Windows API and WinAPI, Win32 is the main set of Microsoft Windows APIs used for developing 32-bit applications. These APIs are responsible for functions in the following categories: Administration and Management - Install, configure, and service applications or systems.
The exit function, declared in <stdlib. h>, terminates a C++ program. The value supplied as an argument to exit is returned to the operating system as the program's return code or exit code.
The company that I referred gave me advise to learn about Win32. But when I begin to learn about it, I encountered that Win32 is C++ based.
Win32 API is a set of functions defined in the Windows OS, in other words it is the Windows API, this is the name given by Microsoft to the core set of application programming interfaces available in the Microsoft Windows operating systems.
Aiiieeeeeeeeeeee. Don't do ANY of these things!
exit() and ExitProcess are the equivalent of taking a gun and shooting the process in the face. I hope I don't have to explain why that isn't nice, especially for processes that are holding shared objects like database handles that might be system-wide. I know that's the norm in Android, but this is Windows and we don't do that 'round here.
Calling PostQuitMessage() directly can cause memory leaks. PostQuitMessage() is intended to be called from WM_DESTROY. It is NOT NOT NOT a message intended to be used to ask a window to close. It's a callback mechanism for applications to post their exit code back to the shell. It is intended to populate WM_QUIT with the application exit code. If you call PostQuitMessage() directly, you will bypass WM_DESTROY entirely. This is problematic because many windows--and child widgets--very correctly perform their clean-up in WM_DESTROY. If you skip this message by lying to the window, you will deny components the chance to clean up.
And since we're on the topic, don't call WM_DESTROY directly either. Raymond Chen of Microsoft has a wonderful article where he explains "Sending a window a WM_DESTROY message is like prank calling somebody pretending to be the police". It's sort of the evil-twin of PostQuitMessage. Instead of exiting without cleaning up, you're asking the window to clean up without exiting. The window manager never knows to remove the components, and you're left with a dead orphan window in memory. Sigh.
The correct answer is to post WM_CLOSE. Anything using the default window procedure will correctly notify the window manager to destroy the window which will cascade on to WM_DESTROY then to WM_QUIT as intended.
If you need different behavior than the standard close, the other alternative is to create a WM_USER or WM_APP message. If your window has a "fancy" WM_CLOSE--say, for example, you give the user a prompt "Are you sure you want to exit?"--and you want to skip that, you may define a custom message with WM_USER or WM_APP and call that in its place. Your app-defined message would implement the default close behavior, and the WM_CLOSE that's tied to the system gadgets performs your fancy behavior.
I hope that helps!
172
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
