It was intended to make the API easier to use, but various automatic garbage collection all had flaws, and making the application periodically clean up temporary memory added cognitive load to using the API, and in many cases was it was difficult to restructure threaded code to handle this.
So, we're largely going back to the original system, where the API returns allocated results and you free them.
In addition, to solve the problems we originally wanted temporary memory for:
* Short strings with a finite count, like device names, get stored in a per-thread string pool.
* Events continue to use temporary memory internally, which is cleaned up on the next event processing cycle.
When the phone is in portrait mode and the window is in landscape mode, the view changes orientation after layoutSubviews runs. In this case we need some way of notifying the application that the Metal view has changed.
This change also decouples the pause/resume handling from the video subsystem on Android, so applications that don't use SDL for video can get application life cycle events.
The semantics for the life cycle events are that they need to be handled in an event watch callback, and once they've been delivered, the application will block until it's been resumed. SDL_HINT_ANDROID_BLOCK_ON_PAUSE can be used to control that behavior, and if that's set to "0", then the application will continue to run in the background at low CPU usage until being resumed or stopped.
SDL_HINT_ANDROID_BLOCK_ON_PAUSE_PAUSEAUDIO has been removed, and the audio will be paused when the application is paused.
Fixes https://github.com/libsdl-org/SDL/issues/3193
This was just causing confusion and anxiety. SDL temporary memory will be automatically freed on the main thread when processing events and on other threads when it ages out after a second. The application can free it directly by calling SDL_ClaimTemporaryMemory() to get ownership of the pointer, if necessary.
This allows threads to free memory from their local pool without affecting events that are queued, and to transfer memory ownership cleanly between threads that are queuing and dequeuing events.
This was added by the Unreal Engine to handle the input focus for popups and dialogs, window types for which SDL3 has built-in, cross-platform support.
This was only ever implemented in X11, and the only purpose was to hint that a client application may want to call the SDL_SetWindowInputFocus() function, which has since been removed, rendering it pointless now.
