Current Perl documentation can be found at perldoc.perl.org.

Here is our local, out-dated (pre-5.6) version:

The AUTOLOAD method, discussed in Autoloading and AUTOLOAD: Proxy Methods, lets you capture calls to undefined functions and methods.

When it comes to undefined variables that would trigger a warning under -w, you can use a handler to trap the pseudo-signal __WARN__ like this:

    $SIG{__WARN__} = sub {

        for ( $_[0] ) {         # voici un switch statement 

            /Use of uninitialized value/  && do {
                # promote warning to a fatal
                die $_;
            };

            # other warning cases to catch could go here;

            warn $_;
        }

    };