>Looks like "extern" is used to bring global symbols into function scope.

a better way to think of extern is, "this symbol is not declared/defined/allocated here, it is declared/defined/allocated someplace else"

"this is its type so your code can reference it properly, and the linker will match up your references with the declared/defined/allocated storage later"

(i'm using reference in the generic english sense, not pointer or anything. it's "that which can give you not only an r-value but an l-value")