SDL_EventFilter - A function pointer used for callbacks that watch the event queue.

       This datatype is available since SDL 3.2.0.

userdata
              what was passed as userdata to SDL_SetEventFilter() or SDL_AddEventWatch, etc.

       event  the event that triggered the callback.

       SDL_EventFilter - A function pointer used for callbacks that watch the event queue.

       Returns  true  to  permit  event  to  be  added  to  the  queue, and false to disallow it. When used with
       SDL_AddEventWatch, the return value is ignored.

SDL_SetEventFilter(3), SDL_AddEventWatch(3)

Simple Directmedia Layer                           SDL 3.2.20                             SDL_EventFilter(3type)

#include<SDL3/SDL_events.h>typedefbool(SDLCALL*SDL_EventFilter)(void*userdata,SDL_Event*event);

       SDL may call this callback at any time from any  thread;  the  application  is  responsible  for  locking
       resources the callback touches that need to be protected.