Useless use of a constant in void context at c:\windows\TEMP\DzTemp.pl line 3 (#1)
    
    (W void) You did something without a side effect in a
context that does nothing with the return value, such as a
statement that doesn't return a value from a block, or the
left side of a scalar comma operator.  Very often this 
points not to stupidity on your part, but a failure of Perl
to parse your program the way you thought it would.  For 
example, you'd get this if you mixed up your C precedence
with Python precedence and said 
 
        $one, $two = 1, 2;
    
    when you meant to say
    
        ($one, $two) = (1, 2);
    
Another common error is to use ordinary parentheses to construct a 
list reference when you should be using square or curly brackets, 
         for example, if you say
    
        $array = (1,2);
    
    when you should have said
    
        $array = [1,2];
    
    The square brackets explicitly turn a list value into a
scalar value, while parentheses do not.  So when a 
parenthesized list is evaluated in a scalar context, the
comma is treated like C's comma operator, which
throws away the left argument, which is not what you want.  
See perlref for more on this.