The post was based up the book The Standard C Library by P. J. Plauger. It's an excellent reference (if a bit dated as it only covers C89) that not only prints

The post was based up the book The Standard C Library by P. J. Plauger. It's an excellent reference (if a bit dated as it only covers C89) that not only prints the relevant bits from the C Standard, but goes into the history behind the functions and provides an implementation.