Of course this very paradigm, combined with the fact that C doesn’t have a proper pointer-and-length type, led to `gets` and around n million other security disasters when bad APIs would just take a pointer without a length and assume there’s "enough" space…

Anyway, the whole "caller allocates" concept doesn’t work too well in the particular case of `gethostbyname`, which as the author mentions, is a complex struct containing several pointers and double pointers, with a potentially unlimited number of different-length allocations one would have to make!