my $s = '::';
my @fields;
for my $s ( '::', ':', '' ){
 for my $lim ( 0, -1 ){
  print "s=$s, limit=$lim\n";
  @fields = split( ':', $s, $lim );
  print "fields=".@fields."\n";
 }
}

##</code><code>##

s=::, limit=0
fields=0
s=::, limit=-1
fields=3
s=:, limit=0
fields=0
s=:, limit=-1
fields=2
s=, limit=0
fields=0
s=, limit=-1
fields=0