C-style function pointers

[Aaron P]

This is a little advanced for me, but I'd rather fix that one line in a 
library somewhere than compile with -d.

I get an error message "C-style function pointer and pointer to array 
syntax is deprecated. Use 'function' to declare function pointers."

Can someone explain how this keyword is used? Given its name, it's 
understandably difficult to search for. :/