SDL_AddEventWatch
Use this function to add a callback to be triggered when an event is added to the event queue.
Syntax
void SDL_AddEventWatch(SDL_EventFilter filter,
void* userdata)
Function Parameters
filter |
the function to call when an event happens; see Remarks for details |
userdata |
a pointer that is passed to filter |
Code Examples
You can add your code example here
Remarks
The function prototype for filter is:
int YourEventFilter(void* userdata,
SDL_Event* event)
where YourEventFilter is the name of your function and its parameters are:
userdata
what was passed as userdata to SDL_AddEventWatch()
event
the event that triggered the callback
filter will be called when an event happens, and its return value is ignored.
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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().
