Perl - fork() example

Here is a small example which demonstrate fork() implementation in PERL.

while(1)
{
   my @children;

   defined (my $pid = fork) or die "Cannot fork: $!\n";

   if ($pid)
   {
     # Parent Process...

     push(@children, $pid);
     wait();
     my $ret = $?;

     if ($ret)
     {
      warn("Abnormal child exit: $!\n");
      $daemon = undef;
      last;
     }
   }
   else
   {
    # Child Process...
    exit(0);
   }

   while (scalar(@children))
   {
     wait();
     my $ret = $?;
     shift(@children);
   
     if ($ret)
     {
       warn("Abnormal child exit: $!\n");
       $daemon = undef;
     }
   }

}

continue
{
  last unless $daemon;
  sleep(10);    
}

Ajax cache problem in IE

By default IE will cache all Ajax requests. If you make a same Ajax request again without clearing cache, every time you will get same data, instead of fresh data.

So, what's the solution?

Solution: Use either the date and time or a random number in the query string to force IE to reload the relevant document.

Example:
var QueryString = "request_id=x";
var DatetimeQueryString = “&datetime=”+new Date().getTime();
var url = “request_url.php?”+QueryString+DatetimeQueryString;
httpRequest.open(”GET”, url, true);
httpRequest.onreadystatechange = update;
httpRequest.send(null);