Regarding your original post, the replies given so far do solve the problem you mentioned.

If the behavior is still not what you expected, then there are other things that you will want to say, because we cannot guess what that expected behavior is.

You say the first and third regexps work. Let me show you that the second also works, and the returned value is '0', just like you want (unless you really mean 'zero' and not '0'.

sub test_url {
    my ( $s, $server ) = @_;
    # return 1;  # Ok to index/spider
    # return 0;  # No, don't index or spider;

    # ignore any common image files
    return 0 if $s =~ /\.(gif|jpg|jpeg|png)?$/;

    # ignore directory listing sorting links
    return 0 if $s =~ /\?(C=N;O=D|C=M;O=A)$/;

    # make sure that the path is limited to the docs path
    return $s =~ m[^/starteam_area/];
}

my $res;
$res = test_url('http://someurl.com/?C=N;O=D');
print "returned value was - ".$res."\n";
$res = test_url('http://someurl.com/?C=M;O=A');
print "returned value was - ".$res."\n";
$res = test_url('http://someurl.com/');
print "returned value was - ".$res."\n";
$res = test_url('http://someurl.com/?C=X;O=A');
print "returned value was - ".$res."\n";

----
#output

returned value was - 0
returned value was - 0
returned value was - 
returned value was -
[download]

Note that I replaced $uri with $s because I don't know what kind of structure $uri is.