We tried to buy some mechanical equipment which can be steered by a computer API. I asked for the doc beforehand. Got something like your example (10 pages of C header). I asked any better docs? Answer:'a real programmer would know how to use this' - well somehow they didnt manage to sell the device to us. Later they managed to email the comprehensive docs (which existed!), but we alread spent a much larger amount (without regrets) to the competition.