SDL_AddEventWatch - Man Page

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

Header File

Defined in SDL3/SDL_events.h

Synopsis

#include "SDL3/SDL.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

Returns true on success or false on failure; call

SDL_GetError () 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

·(3), SDL_RemoveEventWatch(3), ·(3), SDL_SetEventFilter(3)

Referenced By

SDL_EventFilter.3type(3), SDL_GDKResumeGPU(3), SDL_GDKSuspendGPU(3), SDL_RemoveEventWatch(3), SDL_SetEventFilter(3).

SDL 3.2.2 Simple Directmedia Layer SDL3 FUNCTIONS