package MyDie;

my $die_handle = \*STDOUT;

sub mydie {
    my $message = shift;
    # If in eval block, throw exception ...
    $^S and die $message;
    # ... otherwise print message to handle and exit.
    print {$die_handle} $message, "exiting now\n";
    exit 1;
}

1;

##</code><code>##

use MyDie;

sub testfn {
    print "in testfn\n";
    MyDie::mydie("whoops\n");
    print "end testfn\n";
}

eval { testfn() };
$@ and print "caught: '$@'\n";
testfn();
print "end test program\n";