sub foo {
    $c = wantarray;   
    print $c ? "A" : defined $c ? "S" : "V"
}

     (foo(), foo(), foo()); print "\n";   
$v = (foo(), foo(), foo()); print "\n";   
@v = (foo(), foo(), foo()); print "\n";   
__END__
VVV
VVS
AAA