}
$start = gettimeofday();
while (1) {
// if the file size of chatroom.xml is changed, that means new message has been added
if ($xmlh->fileExist()) {
// if data size is changed,
// stop running this while loop to send messages to user
if ($_POST["datasize"] != filesize("chatroom.xml")) {
break;
}
}
// clear the internal cache of file system functions from php
clearstatcache();
// we are not going to run the loop for more than 30 seconds
$time = gettimeofday();
if ($time["sec"] - $start["sec"] > 30) {
break;
}
// stop running the while loop for a second
sleep(1);
}
$output = "";
// output the content of chatroom.xml as XML message
if ($xmlh->fileExist()) {
// open the existing XML file
$xmlh->openFile();
// get all the elements in the XML file
$output = $xmlh->dumpToString();
}
// print the XML output
print $output;
