NAME¶

SDL_AddEventWatch - Add a callback to be triggered when an event is added to the event queue.

SYNOPSIS¶

#include "SDL3/SDL.h"

int SDL_AddEventWatch(SDL_EventFilter filter, void *userdata);

DESCRIPTION¶

filter will be called when an event happens, and its return value is ignored. WARNING : Be very careful of what you do in the event filter function, as it may run in a different thread!

If the quit event is generated by a signal (e.g. SIGINT), it will bypass the internal queue and be delivered to the watch callback immediately, and arrive at the next event poll.

Note: the callback is called for events posted by the user through

SDL_PushEvent (), but not for disabled events, nor for events by a filter callback set with

SDL_SetEventFilter (), nor for events posted by the user through SDL_PeepEvents ().

FUNCTION PARAMETERS¶

filter

an SDL_EventFilter
function to call when an event happens.

userdata

a pointer that is passed to filter

RETURN VALUE¶

Returns 0 on success, or a negative error code on failure; call

SDL_GetError () for more information.

AVAILABILITY¶

This function is available since SDL 3.0.0.

SEE ALSO¶

SDL_DelEventWatch(3), SDL_SetEventFilter(3)