pub unsafe extern "C" fn SDL_SetEventFilter(
filter: SDL_EventFilter,
userdata: *mut c_void,
)Expand description
Set up a filter to process all events before they are added to the internal event queue.
If you just want to see events without modifying them or preventing them
from being queued, you should use SDL_AddEventWatch() instead.
If the filter function returns true when called, then the event will be added to the internal queue. If it returns false, then the event will be dropped from the queue, but the internal state will still be updated. This allows selective filtering of dynamically arriving events.
WARNING: Be very careful of what you do in the event filter function,
as it may run in a different thread! The exception is handling of
SDL_EVENT_WINDOW_EXPOSED, which is guaranteed to be sent from the OS on the
main thread and you are expected to redraw your window in response to this
event.
On platforms that support it, if the quit event is generated by an interrupt signal (e.g. pressing Ctrl-C), it will be delivered to the application at the next event poll.
Note: Disabled events never make it to the event filter function; see
SDL_SetEventEnabled().
Note: Events pushed onto the queue with SDL_PushEvent() get passed through
the event filter, but events pushed onto the queue with SDL_PeepEvents() do
not.
§Parameters
filter: a function to call when an event happens.userdata: a pointer that is passed tofilter.
§Thread safety
It is safe to call this function from any thread.
§Availability
This function is available since SDL 3.2.0.