How exactly do register variables work in C? When should they be used? K&R touches upon them briefly but moves right along. Is there any source in which I can read about them in depth?
So then a variable definition is a declaration that allocates storage for the variable. Unless you can declare an extern variable within a function, then every variable declaration within a function is necessarily a definition. I've never seen an extern variable declared within a function, but it seems like it could actually be a good idea for using global variables from other files within the scope of a single function.