What is the lifetime of a message-only window?

The lifetime of a message-only window in Windows depends on the application that created it and the way it handles messages. In general, a message-only window exists as long as the application that created it is running.

A message-only window is a window that is not visible and is used solely to receive and process messages. It does not have a graphical representation on the screen. Instead, it serves as a communication channel to receive messages from the system or other applications.

The message-only window is typically created using the RegisterWindowMessage function and the HWND_MESSAGE constant as the parent window. The window procedure for the message-only window must be implemented to handle the messages appropriately.

Since the message-only window is not visible, it is not affected by user interactions or window management operations like minimize, maximize, or close. It continues to exist and receive messages as long as the application that created it remains running.

However, it's important to note that if the application terminates, the message-only window will also be destroyed automatically by the operating system. Therefore, the lifetime of a message-only window is tied to the lifetime of the application that created it.

It's a good practice to clean up and destroy the message-only window explicitly when the application is shutting down or no longer needs it. This ensures proper resource management and prevents any potential issues or memory leaks.

Overall, the lifetime of a message-only window is determined by the application that creates it and how it handles messages, but it is typically tied to the application's runtime.