SDL_CloseIO () closes and cleans up the
SDL_IOStream
stream. It releases any resources used by the stream and frees the SDL_IOStream
itself. This returns true on success, or false if the stream failed to flush to its output (e.g. to
disk).
Note that if this fails to flush the stream for any reason, this function reports an error, but the
SDL_IOStream
is still invalid once this function returns.
This call flushes any buffered writes to the operating system, but there are no guarantees that those
writes have gone to physical media; they might be in the OS's file cache, waiting to go to disk later. If
it's absolutely crucial that writes go to disk immediately, so they are definitely stored even if the
power fails before the file cache would have caught up, one should call SDL_FlushIO () before closing.
Note that flushing takes time and makes the system and your app operate less efficiently, so do so
sparingly.