Anonymous subrefs can go out of scope, just like any other variable, but, just like any other variable, you can pass them around:

sub call {
  my ($arg1,$arg2) = @_;
  my $callback = sub {
    my ($arg3) = @_;
    return $arg1 + $arg2 + $arg3;
  };
  call_func_needing_callback($callback);
}

# or even

sub call {
  my ($arg1,$arg2) = @_;
  call_func_needing_callback( sub {
    my ($arg3) = @_;
    return $arg1 + $arg2 + $arg3;
  });
}
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Also note that there are scoping issues with defining named closures within other subroutines (this probably has to do with named subroutines being global), while unnamed subroutines/closures will work as real lexical closures.

I presume this was asked before I moved the brace, but even then no. The scalar would have (which is why I made the correction), but the subroutine sticks around (they're not lexically declared). Had I done this:

{
my $returned_data = [];
my $callback = sub { push @{ $returned_data }, $_[0] };
}
something_wanting_callback( $callback );
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Then yes, that coderef would have gone out of scope.

So, all subrutines are in effect global? Huh.. I didn't know that.

-Pileofrogs

In Other News:
Whoever keeps downvoting me, please tell me what it is that you don't like... I can't get better if you don't tell me what's wrong...

Named subs all reside in the symbol table of the active package when they're declared (if the name is unqualified, that is; it's also possible to stick a sub into another package's namespace by fully qualifying the name: sub Other::Package::foo { ... }). It's also possible to get a sub which is only useable within a particular lexical scope by storing a coderef in a lexical scalar.

{
my $private_sub = sub { print "I'M IN UR SCOPE HIDIN UR LEXICALZ\n" }
## Can be called here
$private_sub->( );
}
## Can't call it here
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