NAME¶

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

SYNOPSIS¶

#include <SDL3/SDL_events.h>

bool 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¶

for more information.

THREAD SAFETY¶

It is safe to call this function from any thread.

AVAILABILITY¶

This function is available since SDL 3.2.0.

SEE ALSO¶

SDL_RemoveEventWatch(3), SDL_SetEventFilter(3)