The mode you set using this function is respected by all functions of the DOS library but please note that if you switch between buffered and unbuffered IO on the same file, you have to use FlushFile() to flush all pending buffers. If you forget to do this, you might end up with data at the wrong positions in your file.
This function is meant for advanced users. Normally, you do not have to care about the IO mode.
#IO_UNBUFFERED(by default, Hollywood will always use