Concurrent::Errorhandler - Error handling mechanism for Concurrent.

    package Foo;

    use Concurrent::Errorhandler;
    @ISA = qw(Concurrent::Errorhandler);

    sub alive { 
        ..
        ..
        return 
        $self->error ("Awake, awake! Ring the alarum bell. \
                       Murther and treason!", $dagger) 
            if $self->murdered($king);
    }




    package main; 

    use Foo;
    my $foo = new Foo;
    $foo->alive($king) or print $foo->errstr(); 
        # prints "Awake, awake! ... "

Concurrent::Errorhandler encapsulates the error handling mechanism used by the modules in Concurrent bundle. Concurrent::Errorhandler doesn't have a constructor and is meant to be inherited. The derived modules use its two methods, error() and errstr(), to communicate error messages to the caller.

When a method of the derived module fails, it calls $self->error() and returns undef to the caller. The error message passed to error() is made available to the caller through the errstr() accessor. error() also accepts a list of sensitive data that it wipes out (undef'es) before returning.

The caller should never call errstr() to check for errors. errstr() should be called only when a method indicates (usually through an undef return value) that an error has occured. This is because errstr() is never overwritten and will always contain a value after the occurance of first error.

error($mesage, ($wipeme, $wipemetoo))

The first argument to error() is $message which is placed in $self->{errstr} and the remaining arguments are interpretted as variables containing sensitive data that are wiped out from the memory. error() always returns undef.

errstr()

errstr() is an accessor method for $self->{errstr}.

Vipul Ved Prakash, <mail@vipul.net>

Concurrent(3)