Those are macros and they just change the byte ordering for networking.
Just because unices use text files to configure everything doesn't mean they *have* to - as if their machine would wake up one day and decide to treat ints as 2 bytes. I suppose unix coders store images and audio as text, too. You still have to know how to read the format.
What's your point, anyway? It's irrelevant to anything I've said. And BTW, those classes, when I say "stores them as complex numbers with accessor functions," that clearly indicates that I'm speaking about something internal to the class and doesn't even begin to suggest whether I store them as text either in memory or on disk. In fact, the original program read the s-params in from a text file.
Since I can't expect my ADC to give me ints in text... I don't know why I'd want to slow things down storing a signal as text on a disk.
Does the program in the first link compile on your Sun OS?