So bad docs because they list a way you don't approve of? They do list a number of different ways. They could have used intval() for example 4 because I prefer it but it doesn't take away from the docs or make them bad.

Do you have a method that makes sprintf with d value invalid?

The article states this as the second bullet point "Use prepared statements with bound variables."

Reading the page I actually think this is pretty good for being language documentation.