$ perl -wE '
    sub meaning () { 42 }
    say meaning();
'
42

##</code><code>##

$ perl -wE '
    say meaning();
    sub meaning () { 42 }
'
main::meaning() called too early to check prototype at -e line 2.
42

##</code><code>##

$ perl -wE '
    sub meaning ();
    say meaning();
    # ... later in code with other subroutine defintions
    sub meaning () { 42 }
'
42