(This is the legacy documentation for stable SDL2, the current stable version; SDL3 is the current development version.)

SDL_EventFilter

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

Header File

Defined in [SDL_events.h](https://github.com/libsdl-org/SDL/blob/SDL2/include/SDL_events.h), but apps should _only_ `#include "SDL.h"`!

Syntax

typedef int (SDLCALL * SDL_EventFilter) (void *userdata, SDL_Event * event);

Function Parameters

userdata	what was passed as `userdata` to SDL_SetEventFilter() or SDL_AddEventWatch, etc
event	the event that triggered the callback

Return Value

Returns 1 to permit event to be added to the queue, and 0 to disallow it. When used with SDL_AddEventWatch, the return value is ignored.

Code Examples

int MyEventFunction(void *userdata, SDL_Event *event) {
    // Do things with userdata and event

    return 0; // Value will be ignored
}

// ...
SDL_AddEventWatch(MyEventFunction, NULL);

Definition Parameters

userdata	The data passed by the original call to SDL_AddEventWatch
event	The SDL_Event representing the event

CategoryAPI, CategoryAPIDatatype, CategoryEvents

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