the properties to query.
the name of the property to query.
the default value of the property.
The value of the property, or default_value if it is not set or not a pointer property.
Threadsafety: It is safe to call this function from any thread, although the data returned is not protected and could potentially be freed if you call SDL_SetPointerProperty or SDL_ClearProperty on these properties from another thread. If you need to avoid this, use SDL_LockProperties and SDL_UnlockProperties.
Get a pointer property from a group of properties.
By convention, the names of properties that SDL exposes on objects will start with "SDL.", and properties that SDL uses internally will start with "SDL.internal.". These should be considered read-only and should not be modified by applications.