If I'm not mistaken, neither of your examples are closures. According to Intermediate Perl, a closure is "just a subroutine that references a lexical variable that has gone out of scope".

The anonymous subroutine passed by reference to find does bind a lexical variable ($total_size). By most definitions (e.g wikipedia's), that subroutine is then a closure. The variable doesn't have to have gone out of lexical scope. The important part is that the subroutine deeply binds the variable, and the variable may go out of scope.

lodin

PS. The code should read sub { instead of { sub, but that's not important for the question at hand.