wiki/doku.php?id=esp8266_gpio_pin_allocations
...showing the setting of the digital pin's function doesn't work as written and I can't find either the library that would make it work or an alternate way of setting the function.
The method shown is pinMode(<pin #>,FUNCTION#). I presume, from the noted page, that the following would work:
pinMode(6,FUNCTION3)
but this gives a FUNCTION3 not declared error so I believe either there's a library that's needed (not mentioned on the page) or the term FUNCTION3 s/b replaced with something (not mentioned on the page).
Can someone clarify this and perhaps add the info to the noted page for others to see.