sub foo {
   print("There are ", 0+@_, " args\n");
   print("They are @_\n");
}

my @a = qw( a b c );
my $n = 123;

foo(@a, $n);

##</code><code>##

There are 4 args
They are a b c 123

##</code><code>##

foo(\@a, $n);

##</code><code>##

There are 2 args
They are ARRAY(0x1829aec) 123

##</code><code>##

populateEventManifest(\@projectEvents, $eventManFh);  # <-- extra \

sub populateEventManifest {
    my( $events, $eventManFh ) = @_;                  # <-- scalar
    foreach my $event (@$events) {                    # <-- extra $
        $event->print($eventManFh);
    }
}