Man page - sdl_appevent(3)

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Manual

SDL_AppEvent

NAME
HEADER FILE
SYNOPSIS
DESCRIPTION
FUNCTION PARAMETERS
RETURN VALUE
THREAD SAFETY
AVAILABILITY
SEE ALSO

NAME

SDL_AppEvent - App-implemented event entry point for SDL_MAIN_USE_CALLBACKS
apps.

HEADER FILE

Defined in SDL3/SDL_main.h

SYNOPSIS

#include "SDL3/SDL.h"

SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event);

DESCRIPTION

Apps implement this function when using

SDL_MAIN_USE_CALLBACKS . If using a standard "main" function, you should not supply this.

This function is called as needed by SDL after SDL_AppInit

returns SDL_APP_CONTINUE . It is called once for each new event.

There is (currently) no guarantee about what thread this will be called from; whatever thread pushes an event onto SDL’s queue will trigger this function. SDL is responsible for pumping the event queue between each call to SDL_AppIterate , so in normal operation one should only get events in a serial fashion, but be careful if you have a thread that explicitly calls SDL_PushEvent . SDL itself will push events to the queue on the main thread.

Events sent to this function are not owned by the app; if you need to save the data, you should copy it.

This function should not go into an infinite mainloop; it should handle the provided event appropriately and return.

The appstate parameter is an optional pointer provided by the app during

SDL_AppInit (). If the app never provided a pointer, this will be NULL.

If this function returns SDL_APP_CONTINUE , the app will continue normal operation, receiving repeated calls to

SDL_AppIterate
and SDL_AppEvent
for the life of the program. If this function returns

SDL_APP_FAILURE , SDL will call

SDL_AppQuit
and terminate the process with an exit code that reports an error to the platform. If it returns

SDL_APP_SUCCESS , SDL calls SDL_AppQuit

and terminates with an exit code that reports success to the platform.

FUNCTION PARAMETERS

appstate

an optional pointer, provided by the app in SDL_AppInit .

event

the new event for the app to examine.

RETURN VALUE

( SDL_AppResult ) Returns SDL_APP_FAILURE

to terminate with an error, SDL_APP_SUCCESS
to terminate with success, SDL_APP_CONTINUE
to continue.

THREAD SAFETY

This function may get called concurrently with

SDL_AppIterate () or SDL_AppQuit () for events not pushed from the main thread.

AVAILABILITY

This function is available since SDL 3.2.0.