Stream->read, stream->write

This maybe a simple questions, but does the stream->read know how to unpack based on the order it was packed?

For example if I:

stream->write(&mMinColour);
		stream->write(&mMaxColour);
		stream->write(&mMinBrightness);
		stream->write(&mMaxBrightness);

I would have to have in my unpackUpdate a read that matches the order exactly. Sort of "take it out in the order you stuck it in" or:

stream->read(&mMinColour);
		stream->read(&mMaxColour);
		stream->read(&mMinBrightness);
		stream->read(&mMaxBrightness);

and if I did:

stream->read(&mMinColour);
		stream->read(&mMinBrightness);
		stream->read(&mMaxColour);
		stream->read(&mMaxBrightness);

mMinBrightness would read what mMaxColour should have been. Corrent?

If this is not how it knows how to unpack the data how does it know?

Thanks,