I'm going to give it my best guess- it will copy up to n bytes, including the null byte if present in n, but not adding a null if the nth byte isn't a null, requiring you to set the last byte to 0 manually, whether that's allocating n+1 bytes or truncating the nth.
Yes, it's the most obnoxious behavior I could think up - Which meant I was sure it was correct, but not the kind of sure I'd want to rely on.
I also refreshed myself on snprintf, and as un-ergonomic interfaces go, they did a good job with what they had... But I will gladly take my golang multiple return values, now that I have them.
So, only when the returned value is non-negative and less than ‘n’, the string has been completely written as expected.
