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Comment: update content - pointers, structs
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| ||'''filter'''||^typedef int (SDLCALL * SDL_EventFilter) (void *userdata, SDL_Event * event); ??? the SDL_!EventFilter to be referenced/run ???^|| ||'''userdata'''||^a pointer filled with user-specified information to be filtered^|| <<Color2(green,Should SDL_!EventFilter have a page? Be detailed in Remarks? Is userdata an exception to the 'pointer rule'?)>> |
||'''filter'''||the name of a function that gets called when an event happens; see [[#Remarks|Remarks]] for details|| ||'''userdata'''||^a pointer filled in with user-specified information to be filtered^|| |
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| typedef int (SDLCALL * SDL_EventFilter) (void *userdata, SDL_Event * event); |
DRAFT |
SDL_SetEventFilter
Use this function to set up a filter to process all events before they change internal state and are posted to the internal event queue.
Syntax
void SDL_SetEventFilter(SDL_EventFilter filter,
void* userdata)
Function Parameters
filter |
the name of a function that gets called when an event happens; see Remarks for details |
userdata |
a pointer filled in with user-specified information to be filtered |
Code Examples
green
The filter is protypted as:
int SDL_EventFilter(void *userdata, SDL_Event * event);
You can add your code example here
Remarks
typedef int (SDLCALL * SDL_EventFilter) (void *userdata, SDL_Event * event);
If the resulting filter returns 1, then the event will be added to the internal queue. If it returns 0, then the event will be dropped from the queue, but the internal state will still be updated. This allows selective filtering of dynamically arriving events.
![/!\](/moin_static198/fixedleft/img/alert.png "/!\"){kind=small}
Be very careful of what you do in the event filter function, as it may run in a different thread!
There is one caveat when dealing with the SDL_QUITEVENT event type. The event filter is only called when the window manager desires to close the application window. If the event filter returns 1, then the window will be closed, otherwise the window will remain open if possible.
If the quit event is generated by an interrupt signal, it will bypass the internal queue and be delivered to the application at the next event poll.
green
*Note: Events pushed onto the queue with SDL_PushEvent() or SDL_PeepEvents() do not get passed through the event filter.*
Related Functions
SDL_PeepEvents *???
SDL_PushEvent *???
