Greetings,

at first the short form of my question(s) - direct from my heart to the monestary public. After that, I provide some more background.

In short:

I recently implemented some code inspired by a CPAN code example. Here is a snippet:

# add one handle and count it
sub add_handle($$)
{
    my $self = shift;
    my $easy = shift;
 
    $$self++;
    $self->SUPER::add_handle( $easy );
}

[download]

Why is it possible to use an object as a counter? Why does this not destroy the object? When I coded a similar thing for testing, the program breaks with the message "Not a scalar reference".

Background of the question:

The example comes form the Net-Curl-package (see https://metacpan.org/pod/distribution/Net-Curl/lib/Net/Curl/examples.pod#Extracted-from-examples/02-multi-simple.pl). I made a successful API implementation along this example. But while adopting the example this special bit of code (the $$self++) looks so wired to me, that I choose to replace it by somewhat more readable ($self->{MULTI_HANDLER_COUNT}++).
But now I did some profiling on the API, and I ask myself, whether there is the essential difference between the official example code and the way I implemented the counting.

I hope someone can give me some deeper insights about the difference.

In reply to Why does $$self++ works? by rob25

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